Issuu

CHAPTER THIRTY-THREE MERCURY

Mercury, a very well-known Metal, is a liquid body which runs like Water, composed by N ature of a viscous and very subtile substance, with much Humidity, because of which it is very heavy, very lustrous and very cold (according to most Authorities). There are not lacking sorne who affirm that it is very hot, in view of the effects resulting from its great Subtility and Penetration, which enable it to pass not only through Flesh but also through the hardest Eones. It is also thought to be hot, because, as is well known, Corrosive Sublimate is a poison on account of this being hot in the highest degree. SolimĂĄn (Sublimate) is nothing more than Mercury, though essentially altered by the admixture of metals with which it was cooked and sublimed; and it is a fact that Corrosive Sublimate may be (and it is) reduced back to real Mercury in a way which will be described later. But, leaving this to those who investigate the Properties of the Elements, the fact is that Mercury has so much in common with the other Metals that, although it is not any one of them, it is convertible into all, not only on account of the Principies of which it is composed (as most Philosophers affirm, and as they prove by the facility with which it unites and incorporates with all other Metals), but also because it can be wholly transmuted into real Metal, like those which N ature bore, and behaves like Metals under the action of heat and the hammer. Raymond explains a number of ways by which it may be converted into Gold and Silver. There is a very easy way, explained in the discourse of Eliana, for converting it into true Lead. Although judgment may be suspended as to the credit to be given to Writings 81

FUNDACIĂ“N JUANELO TURRIANO

ARTE DE LOS METALES

which may possibly not be understood, there are many Eye-witnesses in these Provinces, who to-day have and hoard Silver in large quantities, made out of Mercury with the help of Cupellation, by their own hands. Although the Reagents were furnished by others, there is no room for doubt as to the possibility of this transmutation. Very few were the uses to which Mercury was put, and its consumption was very limited befare this age of Silver. It was used only in the forro of Corrosive Sublimate, Cinnabar or Vermillion, and as Red Oxide powders called Juanes de Vigo. But when it is employed to extract Silver from finely-ground Ores (a process but little used in olden times), it is incredible how much of it is consumed. While the quantity of Silver extracted in this Realm has been enough to enrich and amaze the Universe, it is also true that an equal quantity of Mercury, if not more, has been consumed in the process; for although to-day, at the cost of excessive losses, experience has been gained which permits the more economical use of Mercury, the Miner who is most skilful in the extraction of Silver by its aid loses a weight of Mercury in the operation equal to the weight of Silver he extracts; and frequently he loses more. What the cause of this is, and (what is more important) the Remedy, is one of the aims of this Work, and will be explained hereafter. The treatment of ore by Mercury was introduced into PotosĂ in the year 1574; and, up to this Present, 204,700 Quintales (10,235 short tons) of Mercury have been brought to the Royal Store-house of this Imperial Village for account of his Majesty (without counting the large quantity of Contraband which has been consumed). For this exceedingly great consumption, God has provided us with the great Quicksilver deposits of Huancavelica (in Peru); and in these parts, within the Jurisdiction of Charcas, the Minerals of which I have wished especially to describe to Y our Lordship, this Metal is not lacking among the Abundance of others. There are Mercury mines in Chalatiri, four leagues from this Imperial Village. There F\J.\DACJĂ“N JCANELO TURRIANO

BOOK 1

are also sorne near Guarina, in the Province of Ornasuyo; and, not far frorn M oromoro, which is an Indian town, seven leagues frorn the town of Chuquisaca, sorne rich Quicksilver ore was found; but, on account of the sud den Death (not without suspicions of Violence) of the rnan who tried to discover the Mine, the sarne has rernained concealed to this Day.

FUl\"DACIĂ“N JCANELO TURRIANO

CHAPT ER THIRT Y-FOU R ALLOYS, AND ARTIFICIAL METALLIC COMPOUNDS

Art has also its Metals, and, in the Variety and Multitu de of metallic things manufac tured by its aid, it imitates the beauty of Nature. By mixing of Tin and Copper, Bronze is produced for bells, cannon and other things. For this, one pound of Tin is mixed with from four to eight of Copper, according to the object for which it is intended . The Indians were acquain ted with this mixture , and it served them for giving strength to their Instrum ents and Arms, even as we make use of Steel and Iron, of which they were ignoran t. Brass is made of small pieces of Copper placed in adequate crucibles and covered with Calamina (Calamine) a yellow earthy mineral, found not far from Turco, in the Provinc e of.Caran gas, and also near Pirantor a, in Charcas . Over the powdered Calamin e a large quantity of fine Glass is placed. Heat is then applied, the Copper changes colour, and increases in volume by eight per cent. Various mixture s are made for Mirrors, although the best is composed of two parts of Silver and one of Lead. Besides those mixtures, Cinnaba r, Corrosive Sublima te, Red Oxide of Mercury , Red Lead, Enamel, Slag, Cadmiu m, Smelter Fume, Flowers of Copper, Copper Scale, Verdigris, Copper Oxide, Iron Scale, Iron Blue, White Lead, Ochre, Litharge , Tin Purple and Glass are produced artificially. -Cinabrio (Cinnab ar) is made with one part of Sulphur and two of Mercury , heated and sublimed togethe r in vessels of Glass, or of glazed Earth. Solimรกn (Corrosive Sublima te) is also made of Mercury , mixed with an equal quantity of Copperas, ground to a fine 84

FlfloiDACIร N JCANELO TURRIANO

BOOKI

powder, and mixed with a little strong Vinegar to make a mass. This is sublimed in Glass vessels. Alum is also used for this purpose, and often Salt is added. Mercury is dissolved in Nitric Acid; if the solution be evaporated over a slow fire, the Mercury is left behind as hard as a Rock. Powder this very finely, heat it again in a crucible over fire (this is best done in a Copper vessel), and stir it until it becomes a very bright red. This is the J Precipitado (Red Oxide of Mercury). I tch cure consists of two parts of Copperas and one of Litharge; they are ground and mixed with a little strong Vinegar, and left in dung for forty days. The mixture is then toasted in an earthen pot until it becomes very red. The best Enamel is made of Alum, Copperas and Rock Salt. All colours are given to it, as to Glass. Slag is the substance which is separated from Metal when the latter is melted; it floats on the surface of the molten Metal as if it were Grease. It is the Diaphiges of LatĂn authors. Cadmium (ofwhich there is also an Ore) is found sticking to the sides of the furnaces, especially when Copper is smelted. It is called Botryitis when it is nodular; Stacita when it looks like earthenware; and Placite when it looks like bark. Pompholyx (Zinc Oxide) is a flour-like or woolly substance, which falls to pieces on being touched. It sticks to the walls of furnaces when Metals are smelted, and the vulgar name for it is Atutia (Tutty). Between Pompholyx and Spodium there is very little difference. The latter is the more impure, and is found on the walls of furnaces in which Metals are refined. Copper Flour is made by pouring cold water on hot Copper plates as they are cast from the fore-hearth. Very fine particles rise in the form of smoke, and are recovered on the faces of Iron shovels. Copper Scales are the pieces which are broken off from the Metal when it is hammered and beaten. The scales FUNDACIĂ“N JCANELO TURRIANO

ARTE DE LOS METALES

which are broken off from Iron in this way are called Stomoma by sorne, although this Greek word more properly means Steel. Cardenillo (Verdigris) [Cardenillo also means Red Oxide . of Copper- Translators] is made of Copper by covering vessels containing strong Vinegar with lids of Copper, the Verdigris forming at the end of ten or twelve Days. If, instead of Copper lids, in this process, Iron lids are used, Herrumbre (Rust) is produced. Verdigris is very similar to that substance which is called Vermicular. Take one part of white Vinegar and two of rotten urine, and place them in a copper vessel or mortar. Mix them well until they thicken; then add Salt and Alum (about one-twenty -fourth of the whole) and expose to the heat of the Sun until it coagulates and dries, when the mixture takes the form of little Worms, from which it derives its name. Blue is made by placing thin quicksilvered tin plates, full of holes, in hot dung over a vessel containing a little sal ammoniac. The blue is scratched off at the end of twenty days. If lead sheets are placed over vinegar, White Lead is formed. Place White Lead in an Iron spoon or vessel over a fire, and mix or stir it up well until it becomes very red. This is Sandix (Red Lead). Y ellow ochre is lead heated until it takes the colour of this substance. Greta (Litharge) is produced in the refining of Gold and Silver. Purpurina (Tin Purple) is like Gold Purple, though not very permanent. T ake four to six parts of Tin, and as many more of Mercury, one of sal ammoniac and another of Sulphur. Powder them, mix in a glass vessel, and heat. That which remains at the bottom is Purpurina. The last place in this list we shall give to the most beautiful product of Art, which is Glass. It is made of two parts of transparen t Sand or powdered Quartz and one of Nitre, FUNDACIĂ“N JUANELO TURRIANO

BOOK I

or Rock Salt or Soda, made from the Glasswort. Clean and purify by mixing in a little Loadstone. Another mixture is two parts of the Ash of glasswort and one of the aforesaid Sand, with sorne Loadstone, melted with the required heat in appropriate furnaces.

Fl~DACIĂ“N

JCANELO TURRIANO

CHAPT ER THIRT Y-FIVE THE COLOURS OF ALL MINERALS IN GENERAL

In order that the less Experienced may the more easily acquire a Knowledge of the mineral substances which they may encounter, and by the sense of Sight (the most reliable of the senses) recognize what they find in their Mines, I shall give the Colours of the best known of all the varieties of metals. Of a White colour are sorne kinds of Clay, Alum, Asbestos, Arabian Stone, Judas's Stone, Fuller's Earth, Alabaster, Crystal, Diamon d, Silver, Mercury , Tin, and Marble. Of a Black colour are Bituminous Earth, Jet, Copper Oxide, and Graphit e. Of an Ashen colour are the Earths of Erithria and Melos. Of a Blue colour are Sapphire, the Cyanite , the Turquoise, the Lapis Lazuli, and Azurite. Green are the Emerald , Agate, sorne Borax, Clays and Copperas. Y ellow are Gold, Ochre, Chrysoprase, Chrysolite, and Orpiment. Red are the Ruby, Garnet, Balas Ruby, Onyx, Sandara ch, Coral, Iron Alum, Hemati te or Bloodstone, Copper, Vermillion, Lemnos Earth and Red Ochre. Purple . are the Hyacint h and the Amethy st. The J asper is light Blue. Of Greenish Blue are Verdigris and Armeni an Stone; painters use the latter to make a Greenish Blue. Aphrodisiace (?) is reddish White; the J anto ( ?) is bright Red, tending to White; Batrachites is between Red and Black [Wrong; see Pliny.- Translators.] Manganese is purplish Black; Topaz is yellowish White. Sorne minerals are of many colours, such as Agate, of which ihere are Black, White and Coloured varieties. Apsycto s (?) has red veins spread over a dark ground, while Nosomite (?) is stained with black veins on a red ground. Heliotropia (Bloodstone) has its beautiful green field crossed by blood88

[il ·-

FUNDACIÓN JCANELO TURRIANO

BOOK I

red vems. A brilliant golden sheen may be seen in Sapphires and Lapis Lazuli. Two veins, white and red, run parallel across Egitilla ( ?) . Eupetalos is of four colours: blue, red, vermillion and apple-colour. Orea ( ?) is also found in as m.any colours: red, green white and black.

FUNDACIĂ“N .rt:ANELO TURRIANO

CHAPTER THIRTY-SIX THE PROPERTIES OF VIRTUES OF MINERAL THINGS

I shall end this Treatise with a brief account of the Virtues possessed by mineral Things, from the point of view of Medicines for the human Body, besides their Properties as already described, in arder that those who have to work in Ores may know how to take advantage of them. Sorne minerals operate by virtue of the occult Property of their Essence, others operate by virtue of their elementary Qualities in opposition to the bodily Ailments (when taken· internally). Of the former, sorne are antidotes for Poisons, and others are remedies for different Maladies. Amongst those mineral Things which are antidotes for Poisons, sorne cure Persons affiicted with the Pest; such, for instance, are the Emerald, Lemnos Earth and Armenian Earth. Others are an antidote for one particular kind of Poison, Sapphire in solution being a remedy against the bite of the Scorpion. Sulphur, Saltpetre and Copperas are good in cases of poison by Toad-stools. Salt, as a Plaster, is employed against the bite of the Viper and the Scorpion, and is taken internally to counteract the effects of Opium and T oad-stools. Of those which by occult Virtue cure certain Maladies, sorne staunch the blood in any part of the body, such as Hematite. Others, like the true Jasper, strengthen the Stomach, when they are hung over the latter from the N eck. Others, such as the Aguila Stone, called by the Greeks "Astites," if tied to the left arm, prevent abortions; when tied to the left thigh, this stone has the contrary effect; this is also true of the Jasper. Others, like the Loadstone, purge thiclc humours; others, such as the Armenian Stone 90

FUNDACIÓN JUANELO TURRIANO

BOOK 1

and Azurite, dissipate Melancholy. Others, such as the Armenian Stone itself, Borax, Copperas and Oxide of Mercury, provoke nausea. Among the minerals which have an active effect on the human Body (and nearly all minerals are astringent), sorne heat the body, as for instance, Alum, Copperas, Copper compounds, Fuller's Earth and Verdigris. Others cool the body, such as Earth of Erithria, Antimony, White Lead and Litharge. Others, with the secondary properties which they possess, soften the Tissues, as pitch does on account of the great portion of bitumen which it contains. Others, on the contrary, barden the Tissues, such as Lead and Antimony ores. Sorne open the Pores of the skin, as for example, Nitre and Aphronitre; others, such as Earth of Samos and any other viscous and tenacious Earth, close them. Sorne, such as Sandstone and Pyrite eradicate Warts, Wens and condensed Guros in __the body; others, such as Copperas, and Alum, dry Ulcers. There are sorne, such as Asiatic Stone (?), Copperas and Verdigris, which eat the flesh, and others which rot it, the latter being Quick Lime, Orpiment, Sandarach and Borax. Corrosive Sublimate, Orpiment, Sandarach and Quick Lime also rot the entrails, while Plaster of ParĂs, White Lead and Calcined Tale are also poisonous because they suspend the function of the bowels.

FUNDACIĂ“N JCANELO TURRIANO

FLNDACIÓN JCANELO TURRIANO

SECOND BOOK OF

EL ARTE DE LOS METALES CHAPTER ONE lN WHICH THE READER IS TAUGHT THE COMMON METHOD OF TREATING THE ORES OF SILVER BY AMALGAMATION, WITH NEW PRECAUTIONS FOR ITS USE

The treatment of Ores should not be practised except by him who understands it, and after Examination and License of the Authorities. Such is the Abundance of all kinds of Minerals with which God has enriched almost the whole of these Provinces of this N ew World (through which can be appreciated the other high Benefits of His Divine Providence), and such also is the Fertility of its Veins, that the very Greatness thereof makes it hard to credit. More than four hundred and fifty millions of pesos is the sum that the famous Hill and Imperial Village of Potosí has already given, a sum of which scarcely anyone would be able to conceive, and which would be sufficient to build another very great and beautiful Mountain of Silver. In order to be understood by those who know but little of this enormous Machine (as I may well name it) for the production of Riches, I would ask them to imagine the ground covered with Pieces of Eight (Reales.-Eight Reales equivalent to one peso), so that they would lie as close as possible, one unto the other. In this way they would cover sixty leagues of road, counting twenty-five Pesos to each Vara in length, and five thousand Vara:.to t'he Spanish League. 93

FUNDACIÓN JUANELO TURRIANO

ARTE DE LOS METALES

This great yield has been the reason for the lack of attention to the Losses which have occurred in the treatmen t of Silver Ores. These losses, without the need of exaggeration, would augment by many millions the ciphers of what has not been recovered dueto lack of knowledge concernin g the nature and differences of the ores. They have been treated in a haphazar d manner, without a fundamen tal and definite Knowledge of the Silver which they contained , and which should have been recovered by those charged with the task. This waste is proved by the enormous losses of Quicksilver, the consump tion of which up to the present in this Imperial Village amounts to more than 234,700 Quintales (11,735 short tons). I do not know whether one should praise the magnanim ous Minds (which this superb Climate creates), for their disregard of the Crumbs that might satisfy the hunger for Riches of many Kingdoms of this World, or if one should condemn the N eglect of su eh a prudent and wellgoverned Republic in not making an end of this useless Prodigali ty, through every possible means. The first and most fundamen tal of all Precautio ns (as I see it) is that the post of a Treater of Ores be filled only by one versed in the Art, and then only with license of the Authoriti es and after passing an Examina tion: the more so, because there are other trades under the obligation to do thus, whose Errors are, beyond comparison, of much less importan ce. But little thought has been given to this, up to the Present, by the Owners of sorne milis, because to them it has seemed that what they lost of their own Ores thEy still possessed for later treatmen t in the stored Tailings; and, in respect to the Ores of others, the worse they were treated the greater the advantag e derived therefrom . Poor argument s are these both : the First on account of the doubled Work; the Second on account of being harmful to the Commun ity, though not imp9ssible to understan d.

FUNDACIĂ“N JCANELO TURRIANO

CHAPTER TWO WHICH TREATS OF WHAT THE METALLURGIST SHOULD BE, AND WHAT HE MUST KNOW

Most weighty is the Confidence placed in the Metallurgis:ts, because all the Riches produced by this most prosperous Land are entrusted to them, without reckoning or Account of what part thereof they are bound to return. Their Reputation is the only assurance of their Truthtelling as to what the ores have yielded. There is neither dispute over their sentence nor appeal from it; which is the strongest of Reasons why the urge of their own Interests may incite them to take of the yield unto themselves. Much need of a Christian Honour have they who enjoy these endless Opportunities, having, as the saying goes, "their hands always in the Dough," lest sorne of it stick. With much caution should one look upon him whom hewould charge with the task of treating his Ores, because there. is no bad Substance which might hinder recovery, nor any consumption or loss of Quicksilver (both frequent and sure causes of Loss) which can cause such loss as a Metallurgist with a bad Conscience. Nor is it alone sufficient that his good Habits be examined and approved, if there is lacking the necessary Knowledge of the Art which he must exercise. He must be able to recognize the Ores, their qualities and differences; to determine which are most fitted for Amalgamation and which for Smelting, or if there should be a combination of the Processes. He should know the harmful -substances which accompany ores, and not be ignorant of the way to remove them. He should know. the Accidents which may happen to Quicksilver [Fouling and flouring?-Translators], and the ordinary 95

FUNDACIĂ“N JUANELO TURRIANO

ARTE DE LOS METALES

way of milling on a small scale. And, in all cases, he only can be considered as a treater of Ores, who knows at least how to make a small-scale Fire-as say of finely crushed Ore before amalga mating , in order to determ ine the Silver contained, and to know of a certain ty and not throug h guesswork what he should recover. No Diligence should be omitted to secure this result. Many ducats has the ignoring if this Advice cost this Kingdo m; and even to this day we pay the damages due to the disregard of that Precau tion. I will refer to two cases which have passed throug h my hands, in order that this may be better underst ood. A few years before I betook myself to the Provinc e of Lipes, a Miner there was working, in a certain place called Yanquegua, a vein from which he had taken a quanti ty of very rich Ore, althoug h he did not recognize it. Assayed on a small scale with Quicksilver, it yielded from four to five pesos per Quintal, and at this rate the whole lot yielded when milled. He abando ned the mine because it did not pay. Afterw ard an Indian showed it to me, and, having found ore in the waste dump and in the vein which was but little worked, I assayed it by Fire, and it had nine hundre d pesos to the Quintal, althoug h by an ordinar y Amalg amatio n assay it carne to no more than four or five pesos. I legally located this Vein, which I named Nuestra Señora de Borgoña. At once I erected a mili close to it; whereu pon Miners flocked thither and worked many other veins, from which they took large sums in Silver. In the hill of Santa Juana in the Distric t of Berenguela de Pacajes , there were taken out sorne ores like Sulphides, which by the ordinar y amalga mation assay showed no silver or very little; they were thrown away by the Miners , until a friend of mine, a Priest, sent me a sample to Oruro, where I was at the time. I assayed the Ore and found it to have sixty and more pesos to the Quintal. My friend picked up, on my advice, a quanti ty of the Ore, accompanied by the Laught er of those who saw this enterta inment , but who later envied the great Riches taken out by him. FUNDACIÓN JL:ANELO TURRIANO

CHAPTER THREE THE RECOGNITION OF ORES, AND THE DIFFERENT KINDS OF ORES THERE ARE

Most difficult it would be to try to give written Rules for the recognition at sight of Ores, to those who never have handled them. Moreover, so great is their Diversity that it is rare that one Stone from a vein will resemble another, and this not only in different mining Districts, but even in the same Camp. N otwithstanding this, the Miners ha ve reduced ores to three general Kinds, or general Divisions: these are Pacos, Mulatos and Negrillos. Paco (Oxide), in the common language of this Land means a reddish Colour, which, more or less burnt, is the ordinary colour of Stones. Therefore, ores of this colour are called Pacos, although this name also is applied in Berenguela de Pacajes to green Copper ores. In these Provinces, ores of whatsoever colour (except they be Steely and Brilliant) are called Negrillos (Black Ores). Mulato ore is midway between Paco and Negrillos, Nature having created it thus between the two; it is dull in colour and ordinarily it is accompanied by sorne Pyrite. There is less of this than of the other two sorts. Negrillos get their name from, and are recognized by, their Colour, although not all black (Silver) ores are comprehended in the name of Negrillos. Tacana, a rich ore, is ordinarily black; when brown and ashy, it is called Llipita, and belongs to the class of Pacos. Plomo, which is the name given to native Silver when it may happen to be black or ashy brown, also belongs to the Pacos. When it is green, or white and orange-coloured it is called Suco (Chloride). And in the past year there was taken out of this Hill of PotosĂ an ore of the most florid and vivid colour of Cin97

[it]

FID:DACIĂ“N JCANELO TURRIANO

ARTE DE LOS METALES

nabar or very fine Vermillion (Ruby silver), a thing which I have never seen in other mining district. The Soroches (Galenas) by themselves might constitu te a fourth class of Ores, but they can be grouped with others which are similar, under the name of Negrillos. To this class also may be assigned Rosicler (Prousti te), the richest ore which N ature creates under the appeara nce of a Stone. It is shining and easily broken; the fine powder resulting, when it is broken by whatsoe ver hard substance, is of the finest blood-colour. It is very like unto the Cinnaba r or Vermillion which one makes from Quicksilver and Sulphur , and which gives one so little thought of greater Secrets [Probab ly referring to Alchem y.-Tran slators]. Cochizo (Pyrarg yrite) , almost of this same class, is a very rich Ore, solid, not so easily broken nor so leafy as Ruby Silver; it is darker, and does not give the pronounced and perfect colour of Blood, like Ruby Silver. By that which follows one may distinguish the ores called Somche, Tacana, Polvorilla, Rosicler, Cochizo and N egrillo: Soroche may be black and shiny, or ashy and without life, when it is called Dead Ore of Lead; it may carry Silver. Tacana (Silver Sulphide) is Silver hidden by a solid black colour, without any Shine whatsoever. Polvorilla is Tacana which is neither massive nor stone-like, very rich in Metal. Pacos mixed with Negrillos are not so rich, on account of the mixture with Copper. Rosicler and Cochizo are Silver hidden by a Varnish, which gives to them a colour and lustre that distinguish them from Tacana. Negrillo prevails principally with Copper, either as Copper metal or with Copper Sulphate, where it m ay be abundan t. I t carries more or less Silver and is commonly accompanied by Pyrite. A black ore which is heavy, smooth, and leafy or feather-like has much Alcohol or Antimon y. In sorne parts it is called Mazacote; it carries but little Silver. The kind which is said to be mirror-like and steely, on account of its greater Iikeness to a Mirror, or to polished Steel, is the richer, and approximates the more to Rosicler.

FUNDACIĂ“N JCANELO TURRIANO

CHAPT ER FOUR THE SHOVELLING OVER OR SORTING OF ORES, AND THE PROPER METHOD WHICH SHOULD BE APPLIED TO EACH CLASS OF ORE IN ITS TREATM ENT

A good beginning toward recovering the Values of Ores is made by first sorting them. The lack of this is a thing which has caused much Damage and yet it has been given but little Though t. There has been shown a lack of Investigation, not only in that the Ores have not been set apart from the Stones which are not ore, but also in that the same Ores have not been sorted out the one from the other, according to their differences and kinds. The lesser damage has been in the treatme nt by amalgam ation, through the unnecessary transpo rt, the milling and other expenses, and loss of time in treating that which was not ore; the greater damage was that in treating waste and ore, the ore value was not recovered. Frequen tly ores have been treated together which requircd different methods and different periods of treatme nt. To amalgam ate ore which requires smelting is to lose it. To charge in the furnace that which is not adapted thereto is to disturb, damage and accomplish nothing. Even if the Ore be such as to fall within the province of Amalga mation or Smelting, still there are differences and degrees of easy treatme nt (if the ores concord in the method of treatme nt) which may be dangerous if there is necessity to treat them differently. Paco (Oxide) ores which have nothing that shines or reflects light are those adapted to Amalga mation. Tacana (Silver Sulphide) also comes under this Class, although, on account of being a rich Ore, in order that nothing may be wasted, and that nothing may be lost in tailings, it is best to smelt it on a 99

FUNDACIĂ“N JCANELO TURRIANO

100

ARTE DE LOS METALES

Lead Bath. That which is called Plomo (Native Silver), if it is exceptionally coarse, does not grind well nor is well taken up by Quicksilver, should be set aside for smelting with Tacana (Sulphides). The proper treatment of the finely crushed Plomo (metallic Silver ore) is Amalgamation, the treatment for galenas is Smelting. Ruby Silver and Cochizo should be smelted like Silver Sulphide. Negrillos [Sulphides in general.-Translators] are more adapted to Smelting than Amalgamation, although all may be prepared by fire for giving up their Silver by Amalgamation, after they are cooked or roasted, as will be explained farther on.

FUNDACIĂ“N JCANELO TURRIANO

CHA PTER FIVE THE RECOGNITION AND REMOVAL OF THE BAD SUBSTANCES IN ORES

Various, and of many different Qualities are the thing s which, jointl y with Ores, N ature creates in her veins, eithe r by abortions caused by huma n Greed, in takin g them out of the entra ils of the Earth before their due time, when other wise, if duly seasoned in them they would result in perfect Ore; or, it may be that they are taken out as a super fl.uous excre ment result ing from the gener ation of all sorts of Ores. Thes e are Salts, Alums, Vitriols, Sulphur, Orpim ent, Drag on's Blood, Antim ony or Alcohol, Bitum en, which is called Grasa (Grease), white or black, and Pyrit e. Few are the ores extra cted which are not mixed with one or more of these Distu rbers , and all are dama ging when it come s to recovering the value, eithe r by Quicksilver, or by Fire. The Vitriols, to which class belong those called Copa quiras (Cop per and lron Sulphates) are morta l enem ies of Quicksilver; they rende r it useless and consume it, and the more so if their evil disposition is intensified by mixin g with Salt, because their penet ration thus becomes more violent and quickened. This natur al Antip athy was well known to, and writt en abou t by, the most learned Raym ond. Ever y day this matte r is touch ed by those who treat Ores, but they do not stop to think abou t it. Copaquiras devou r Quicksilver, lower the yield, and cause the loss of Silver which is so costly in treati ng the ores which conta in lron, Lead , Tin and Lime. He who would care to show himse lf quick ly the Truth of this may mix an Ore with sorne groun d Vitriol and add a little Quicksilver; he will see after the first Grind ing that the Quicksilver is fl.oured and that all is lost 101

[ii]FVN DACJĂ“ N .JCANELO TURRIANO

102

ARTE DE LOS METALES

in an instant, the more quickly if a little Salt is added. This is not marvellous to those who know that SolimĂĄn (Sublimate) is Quicksilver, and that the great Transm utation in the mix was caused by the Vitriol and Salt with which it was mixed and sublima ted in the heat of the Fire. This Vitriol is the worst Poison found in the treatme nt of ores with Quicksilver, although there are times when it may be utilized, and serve as an antidote with sorne sorts of ores, which demand it, as will be explained in the proper place. With much ease this trouble is recognized, and remedied. Grind up a little of the Ore, throw in pure Water [Free from sulphate s.-Trans lators]; stir it, and allow to settle somewhat; pour the clear Water into another cup, without stirring up the sediment. On testing it, there will either be no taste, or a styptic and sharp taste. Further , he who would care to add to this testimo ny that of Sight, may heat over a slow fire this (clear) Water, until it is evapora ted, and he will see with his own eyes, in the Sedimen t which remains, the Alum or Vitriol. Wash the ore in the way indicate d as many times as may be necessary, until the Water comes off sweet, or until, when it is stirred with a clean Iron, the same is not covered with the colour of Copper. Thus it will be exceedingly cleansed, and of a surety the Quicksilver will not be damage d through this substanc e. Sulphur , Pitch, and Antimo ny, although they frequen tly show their presence to the Sight, prove it better through the odour they give off when burnt in the fire. However, they may be more satisfact orily recognized and removed by the following Procedu re: After the Ore has been coarsely broken, it is placed in a vitrified clay Jar which has in the bottom many small holes. The mouth is then closed, and the jar is adjusted in an Indian wind furnace, which is fired in the same way as when Amalga m is retorted . Undern eath the aforesaid Jar is another which contains Water, and into which it fits. In this lower Jar is collected the smoke which comes through the holes in the bottom of the upper Jar. FUNDACIĂ“N JCANELO TURRIANO

BOOK II

103

On examin ation one may see, solidifi.ed and swimming on the Water, the Sulphu r, Antimo ny or Pitch, each one in its proper form. The fact that no more smoke issues forth is a most certain Sign that the Ore is freed from these impediments, which, while in the crude ores they may not directly affect Quicksilver, will affect it throug h that Varnishing (Fouling) which they cause, preven ting the Quicksilver from uniting with and recovering the Silver. Furthe r, there is the rapidit y with which, throug h the glass-like quality inheren t in all Ores, the Quicksilver is cut up and dissipated into a white powder (Floure d), when the Ore is gro un d. It is necessary to roast th~se kinds of Ores, even to sintering, before chargin g in the strong fi.re of the Furnac e; because without this prepara tion the Silver will be conver ted into .slag. Pyrite is easily recognized in the Ores which carry it. Throug h its weight and glassiness it helps to flour the Quicksilver in milling. With fire its avid and evil Influence may be removed by roastin g it until it has lost its lustre. Where it most disturb s is in the smelting of ores. On accoun t of the abunda nce of impure Sulphu r contain ed, and with which it is begotte n, there is formed a blanke t in smelting, which fouls the bath.

FU~DACIĂ“N JLANELO TURRIANO

CHAPTER SIX GRINDING THE ORES

The grinding of Ores is precisely the preparation necessary to get out by Amalgama tion the Silver and Gold contained therein. lt is very necessary that the pulp be fine, to shorten the treatment and recover the Silver that may be contained. One error, among others, to which but little attention has been paid by the majority in this Country, is that of grinding too coarsely, or to the state of Sand, instead of to Slimes. But little is needed to convince any person that Quicksilver attracts and incorporate s into itself only that Silver with which it is in immediate contact, and that that which may be inside of a grain of Sand will remain there with the so much greater or lesser loss, as the Ore may be more or less rich, and the pulp more or less coarse. Various experiment s I have made in regrinding these Sands, and the least that I have found has been around a sixth of the Silver recovered in the original treatment. This means an enormous sum in each year, and it is incredible what it means in the years gone by, in which we have milied so much rich Ore. Georg AgrĂcola, after showing the method of grinding and screening Ores, as practised to-day in treatment plants, is explicit in stating that the reduction to the finest of Flour should be done in a mili, with stones like unto those of flour milis. T o him this fine grinding did not seem justified, as its object was very different to that sought in our practice, in which fine grinding is precisely and clearly necessary. [Barba probably refers to coarse grinding preceding concentrati on of sulphides, as against fine grinding or sliming for amalgama tion.Translators.] 104

FUNDACIĂ“N Jl:ANELO TURRIANO

BOOK II

105

I know a person to whom the taking advantage of this Advice meant many Ducats, when he reground a quantity of sand tailings which the stamp did not crush fine enough, either because the Ore escaped the blows, or the particles defended themselves, one through the other, against being crushed. T o have good Screens and to be careful in taking them out means much, but it does not remedy everything. After the clean-up, especially if the Ore was rich, he will be doing wisely who collects and retreats the Sands. If he roasts the Sands he will obtain more fine Sand because (for one · Reason) the Ore becomes softer, and (for another Reason) it becomes spongy and presents more body on which the blow of the stamp may act. I use another treatment, by calcining, which will be discussed later. It is better adapted for all milling by Amalgamation. The ore, being ground and screened, is thrown into a hand-tub, as if it were already a pulp to which had been added the requisite quantity of Quicksilver. To wash it, throw in sufficient Water, and stir it up very well with the paddle. All the fine will be suspended, and the coarser, or badly ground, will be on the bottom. Take out the slimes with Bateas, throw into cauldrons and boíl. The coarse sand is reground, either in Arrastras, or in sorne other grinder, until all is reduced to a fine Flour. If it is desired to make up charges of the slimes to be treated in the ordinary way, they should be mixed with clean fine Sand in arder to make them porous and avoid the inconveniences of slimy ores.

FUNDACIÓN JCANELO TURRIANO

CHAPTER SEVEN ROASTING ORES

To secure two Results it is of importance to roast Ores, either that they may grind more easily, or to put them in such condition that Quicksilver will embrace and become incorporated with the Silver. The reason of the First is clear, and experience of the Second is common, especially as by this method the black ores (Negrillos) are treated. However, the fundamentals of Roasting are generally unknown, and there has never been any other thing carried on in such a careless,happ y go-lucky and unscientific manner. Amalgamator s claim that they roast Ores in order to remove the evil substances contained; they do not stop to think that if this were so, the more fire they used the more the Ores would be cleaned and purified. However, they experience the contrary, because, keeping pace with the lengthened roast, the evil substances become augmented and more avid. Thus increases the necessity of more Reagents to resist the evil effects; and the penalty is to recover from the ores neither Silver nor Quicksilver. One enemy alone does N ature oppose to Quicksilver to corrupt and destroy it, as has been said before, and that is Vitriol. Not alone is it not removed by fire from the ores, which it may be necessary to roast; rather it is multiplied and augmented; and even if it is not present in the ores when charged in the furnace, fire will produce and beget it. This is a thing easy to experiment with and see. Therefore, why marvel, when sulphide ores are roasted (augmenting more and more this enemy of Quicksilver), that greater quantities of Reagents should be needed to repair the damage? N evertheless, had it been understood, the evil effects might have 106

FUNDACIĂ“N JCANELO TURRIANO

BOOK II

107

been remedied with greater ease and less cost by washing the Ore, as I have already said, until all the Vitriol departed. A lack of this knowledge has occasioned many losses and expenses. The other evils in themselves are not harmful to Quicksilver; solely they hinder the Silver from being incorporated with the Quicksilver and forming Amalgam, on account of the glassiness or varnishing which they produce (Sickening). The surest rule in these Parts for judging the progress of the Roast is that the ore shall change colour, and that it should lose all of its former shine and brilliance; the said shine and brilliance, if the ores are to be treated by Amalgamation, indicate the necessity of roasting. The Pacos (Oxides) are not harmful to Quicksilver; if they contain any mixture of the above-mentioned (Sulphides) a roast is necessary.

FID.'DACIĂ“N JCANELO TURRIANO

CHAPTE R EIGHT THE BAD EFFECTS WHICH RESULT FROM ROASTING ORES

Even as men have proceeded up to this day without any certain knowledge of the Silver which the ores have carried, just so he has been judged to be the better Amalgam ator who recovered the most from one Working producing one kind of Ore. There always remained an honest doubt if the ore did not have more to give up. The roasting of the black Ores and others is even yet looked on with suspicion, because there has been so little attention paid to it. There has always been fear of experimenting, because, as the saying is, it is better to play one card too little rather than one card too much. In effect this method of treatmen t has been considered more dangerous than advantag eous. Many mira eles of N ature will be observed in the roasting of ores, by him who observes with Intelligence. The Iron which they have, when burned with the Sulphur which ordinarily accompanies it, is converted into Vitriol, or Green Caparrosa (F errous Sulphate ); this later is transmut ed to fine Copper. [This is an error.Translators.] Copper also, when roasted in the same kind of furnace, is calcined and dissolves in water like Salt; strained and evaporate d over a slow fire, it solidifies to another Vitriol, or Blue Caparrosa (Copper Sulphate) like that which is called Lipes Stone. It has the admirable power of convertin g almost all the metals into Copper; even the purity of Silver itself will not protect it against changes of this sort. If Silver ores partaking of Alum, Caparrosa (Sulphate s) and Saltpetre or nitrate-be aring Earth are calcined, the Silver breaks up and dissolves, thus 108

FUNDACIĂ“N Jt:ANELO TURRIANO

BOOK II

109

making it impossible for the Quicksilver to take it up, except through sorne new Artífice. Moreover, Salt alone, either begotten with Ores or mixed in the roast, is sufficient to produce the same effect, as I will show by the practica! evidence of the following experiments.

FUNDACIÓN JUANELO TURRIANO

CHAPTER NINE EXPERIMENT S THAT PROVE THE DAMAGE FROM ROASTING ORES, UNLESS THEY ARE RECOGNIZED AND REMEDIED OPPORTUNELY

Grind a little Ore which may have Copper or Iron, and, according to the method described in Chapter Five (of this Second Book) examine for Caparrosa (Sulphates). Remove completely by washing. After it is dried, roast very well, throw into water again, and there will be seen much Caparrosa (Sulphates) newly produced by the roast. This is a common occurrence though few have stopped to give it a thought. And, although this Experiment should be enough to satisfy any Person, for further Proof I give another. Beat Copper or Iron into thin sheets. Grind Sulphur, and in a crucible or vitrified pot put a bed of this powder, then one of the sheets, and so on in this order with what is disposable, or what the capacity of the Vessel allows. Cover the mouth, and lute tightly. When dry, place among lighted Coals so that they surround it, but do not touch it. After a time, when the crucible is sufficiently heated, the fire should be brought nearer, and finally increased. The heat, though, should not be sufficient to melt the sheets. T ake them out, and they will be found to be black and brittle. Grind finely; add ground Sulphur to the fourth part of the weight. Place in a pot-sherd, or open scorifier over the coals. Roast as when making an assay of Negrillos (Sulphide) ore, stirring constantly until the Sulphur ceases to smoke. The more times this is repeated the better it will be. Lastly, when well ground and heated, throw it into water or water upon it; at the end of a short time, decant off the water. If a 110

FUNDACIĂ“N Jl:ANELO TURRIANO

BOOK II

111

clean iron is put in the water it will take on the colour of Copper. [If the sheets were copper.-Tr anslators.] Evaporate over a slow fire until a scum appears; allow to cool and it will crystallize into most beautiful and transparen t green Caparrosa (F errous Sulphate) if the sheets were Iron, or blue · (Copper Sulphate) if the sheets were Copper. Dissolve this Caparrosa (Sulphate) or Lipes Stone in water. If a piece of Steel or Iron is put in the solution, it will go on converting itself into the finest Copper, smooth and soft like Gold, after it has been melted. If Lead or Tin is granulated and cast into the solution, all the surface is quickly converted to Copper; and the more frequently this is repeated the more of the Lead is transmuted, until it is all converted. The Tin is very quickly changed to Bronze. I was the first in the Province of Lipes to discover and publish these secrets. Silver also will precipitate the Copper if it is exceeding fine, and if considerable Salt is added. However, the reverse of this reaction is more to the liking of Metallurgis ts. Agua Fuerte (Nitric Acid) is an ordinary substance, which, were it not so common, would be considered as having marvellous force, for it converts Silver to a liquid. It is made from Caparrosa (Copperas) , Alum, and Saltpetre. The vapours which come off from these ores ( ?) when roasted in the furnace have the same effect on ores as Nitric Acid. From ground Brick and Salt, especially Rack Salt, there is prepared that which is called Cimiento (Cementati on Powder), with which Gold and Silver are parted. The Nitric Acid attracts unto itself the Gold and Silver, and alone burns them with the violence of fire. In the roasting of ores the same effect on Silver is obtained, if it is calcined in one of the ways indicated. The nitrate solution, when thrown into salt water, whitens it like Milk; it also stains the N ails and Hands when touched. These are typical effects of the solution made from Silver dissolved in nitric acid. Metallurgis ts should give much thought to this in arder not to lose the Silver. FUNDACIÓN JUANELO TURRIANO

112

ARTE DE LOS METALES

These inconveniences go hand in hand with the roasting of ores when there is not a competent Person to watch. Oftentimes, to overcome these difficulties, the proper way is to smelt the ores, utilizing not only the high-grade, but also the low-grade ore, as will be described in the proper place. However, not in all Parts are there the necessary factors for smelting, nor have all Ores the necessary values to support the costs thereof. The said troubles [Incidental to roasting preceding amalgamation.- Translators], when they occur, may be remedied as laid clown in the warnings hereafter. However, it is now possible to prepare ores so that without any Roast whatsoever they will give up their Silver by amalgamation, as will be explained in the treatise on amalgamation by cooking [Pan amalgamation.-Translator s].

FUNDACIĂ“N JL'ANELO TURRIANO

CHAPTER TEN

WHETHER ORES SHOULD BE ROASTED IN CHUNKS OR CRUSHED FINELY Ores are sometimes roasted in Chunks, and sometimes finely ground befare roasting. The better practice is to have the ore finely ground, taking care to stir it uniformly in the furnace. By removing a little and mixing with Salt and Quicksilver, one may know, in a few minutes, the amount of Quicksilver necessary, how much Silver the ore carries, if the Sulphides are well reduced, if the metallic Silver is coarse or fine, and if much or little of the Reagents will be required. The roast will be continued or stopped in conformity with what the Experience of each Amalgamator has shown to him to be the best practice. In ore which has been roasted in Chunks, no uniformity of roast is found, because the force of the Fire has not been equally distributed, on account of the unevenness of the bed, and the size of the Stones. It is clear that the smaller pieces are roasted befare the larger ones, and that those in the middle of the furnace and in the centre of the Fire are roasted befare those on the sides. However, in roasting in chunks there is less likelihood of over-roasting, and there is the added advantage that the coarse-roasted ore is more easily ground. Much in error is he who roasts finely ground ore in a Reverberatory. So strong is the fire that all the Sulphur or Pitch which the ore contains, instead of being dissipated slowly, mixes with the Silver, and all is lost as Slag. Furthermore, the draft willlift up the fine Silver when the charge is stirred and, entangled in the Smoke, it will be carried out of the furnace. A Muffie Roast is the safest for ground ore; the kind of furnace adapted thereto will be described here113

[il

FlJ.'lDACIĂ“N JCANELO TURRIANO

114

ARTE DE LOS METALES

after. Finely-ground ore may hall up, and even if this does not happen, it will at times become a spongy mass, and somewhat lumpy, because of the Fire; wherefore it is best to regrind before making up the amalgamation charge. The surest way is to roast the ore in chunks, which will facilitate, as has been said, and also shorten, the grinding. Thus ceases the loss of the fine Silver going off in the smoke. It is best that the hard Quartz ores, which it may be necessary to roast, and which are less juicy [Lower in sulphur.-Translators] should be so treated. Others [Massive sulphides.-Translators] should not be roasted alone, but finely ground and mixed with other ores, according to their deficiencies, as will be explained.

FUNDACIĂ“N JUANELO TURRIANO

CHAPTER ELEVEN THE THINGS ONE MUST MIX WITH ORES TO ROAST THEM

Not an extraordina ry thing, but very common, is the begetting of Iron jointly with Gold and Silver ores. Those ores which partake of lron are the most rebellious in roasting and the most difficult to smelt; the slowness with which heat penetrates the iron ore has already been commented on. If a piece of Piedra lman (Magnetic Iron Ore) is passed over the very well roasted and ground ore, there is lifted up more or less, according to the abundance of lron the ore contains. This class of ore, after it has been well ground, should be mixed with Sulphur, or better, with ores which may have Sulphur. Ground Antimony also, in the proportion which the quantity of lron may require, is mixed with the ore and muffie-roasted slowly, until, when a small portion is taken out and tested as usual, it is found to be well conditioned . Sulphur is the Destroyer of Metal, from whose influence only the perfection of Gold exempts it. Tin is offended the least, and lron the most, by Sulphur. This is the reason why, when these two opposed substances come in contact in the furnaces in which they are roasted or smelted, they become mutually destructive and leave the Silver free. In the same way may be cured those ores which have Sulphur or Antimony, by mixing and roasting them with lron ores or slag. Those ores which contain Orpiment or Dragon's Blood are roasted with Soroches (Galena). Those which have black or white Pitch [Carbonaceous matter.-Tr anslators] are roasted with slag of Iron, and finely ground white Stone, from which Lime is burned. 115

FUNDACIĂ“N JUANELO TURRIANO

116

ARTE DE LOS METALES

ln addition to the method indicated above, one may recognize the mixtures in ores by the colours of the Smoke which comes off when a little coarsely ground ore is placed on a well-heated iron plate. If the smoke is White or Black the ore contains Pitches of those colours. If it is Yellow, it has Orpiment; if red, Dragon's Blood; 'if in the centre it is Y ellow, with the edges Green, it has Sulphur. N evertheless, the Earths mined with ores at times give off in their smoke similar colours.

Fill<DACIĂ“N JCANELO TURRIANO

CHAPTER TWELVE WHAT THE AMALGAMATOR SHOULD DO BEFORE MIXING THE CHARGE

Duly appreciating all the aforesaid (although the Sorting does not come within his province), having ground and screened the Ore to the necessary fineness, and with the intelligence demanded, before he starts to make up the charge or roast the Ore (should there be necessity), the Amalgamator should make an Assay in the following manner: Set apart three or four pounds of Ore fin el y ground and freshly mixed. On a small quantity make two Fire-assays in the manner to be explained later on; there will then be known to a certainty the Silver which the charge contains, and what should be recovered; or, we may suppose for a beginning that the ore is a pure Paco [Oxide, gossan.Translators] not needing a roast. If it contains Copperas or Blue Vitriol they should be removed, as has been said befo re. Test one pound by amalgamation, using the least Water possible; allow to settle a little. If there arises to the top a cream-like Scum, which is the grease or Unctuousness of the ore, it should be drained off and washed as much as necessary with clean water, to remove this disturber. Pour off the superfluous water; throw in Salt and Quicksilver, and, using no other reagent, proceed with the amalgamation. Always take note of the condition of the Quicksilver; whether it runs together well; whether it picks up the Silver well; if it flours or if it fails to amalgamate. If the Quicksilver begins to disappear it is a sign that the Ore is taking it up. Continue the amalgamation until it can be seen whether the attraction of the Silver and the continued workings have spent the Quicksilver; this only happens 117

FUNDACIĂ“N JCANELO TURRIANO

118

ARTE DE LOS METALES

when the treatment is excellent. Continue until the Silver shows up like very fine Filings. When Quicksilver is no longer taken up, wash the test, and the recovery based on the Fire-assay can thereby be determined. The ores of Berenguela de Pacajes are like to the aforesaid, and in the beginning many ducats were lost there on account of amalgamation with many reagents, as these ores were thought to be impossible o(treatment otherwise. To-day they are treated with only Salt and Quicksilver, and they yield up in this way even as they would in smelting, that is, all the Silver contained. These ores are of the sort that bear Copper. If the test shows "Lead" (for it is thus they call it), that is, if the Quicksilver loses its lively colour [ls sick.Translators], and assumes a look of Lead, there is need of sorne material to clean it, so that it will the better embrace and recover the Silver. The materials possessing this Virtue are finely divided Iron, Lead, Tin and Quicklime; Ashes also have a like effect. Any ore whatsoever may be treated with any of these materials, although, for the reason of natural Convenience and Concord, it is more appropriate to use the substance which is more symbolical of the ore mixture. If the floured Quicksilver is very dark and inclined to Black, Iron is more appropriate; if lead-coloured, Lead; if lighter still, Tin. To golden Quicksilver (so coloured by Copper) should be added Lime. Little by little, by count and measure, there will be added the reagents necessary, until the Quicksilver remains clean and takes up the Silver. The quantities necessary to add to the full scale charge can then be calculated according to the weight to be amalgamated. If the Quicksilver becomes floured, and this has not been caused by excessive grinding in the amalgamation, then the cause of the flouring proceeds from the Baseness of the Ores, a typical trouble with Galena and Pyrite, and the other shining Ores; therefore it is necessary to roast them, as has been said befare. Rocks without Silver content may FUNDACIĂ“N JUANELO TURRIANO

BOOK II

119

cause the same trouble to Quicksilver, and, although the Quicksilver may be cut up into a fine white powder, if the material treated is neither raw Black Ores nor Pyrite, there will have been no Silver in the ore tested, and no attention need be paid to it. If the Quicksilver remains clear and runs together well in the preliminary test, and continues to take up the Silver, there is no necessity of other reagents. All tests should be started with only a little Quicksilver, in o.rder that it may be added as co~venient. If possible, add an Excess, because the treatment is then surer and shorter, as will be explained later. Furthermore the Amalgamator should leave nothing undone until the small-scale amalgamation test corresponds in recovery to the Fire-assay result. According to the result attained, he will proceed in the treatment of full-scale charges.

FUNDACIĂ“N JUANELO TURRIANO

CHAPTER THIRTEE N THE WARNINGS OF THE LAST CHAPTER IN REGARD TO ROASTING ORES ARE CONTINUED

If the ore should of a necessity have to be roasted, in conformity with that which has gone before (after the Fireassays have been made, and the Silver content is known) the Amalgama tor will do so, heeding the Warnings aforesaid in regard to the mixture and quantity to be treated, and taking into account the facilities there are for work. Ores should not be roasted with Salt, because, while it aids in the calcination of the Silver, it penetrates the ore, thus harming the Silver. [Loss by volatilizati on as silver chloride.Translators.] One cannot fix precisely the number of Hours the ores should be roasted, although it is a sure rule that they are sufficiently roasted when, upon a little of the pulp being tested, the Quicksilver remains in globules, stays bright and takes up Silver. This effect is never in doubt if the firing is persevered with, and the ores are roasted with the right mixture and in the correct quantity. These factors, as in the case of Pacos (Oxides), will be determined by smallscale tests, by which one may know how much material (reagents) has to go into the furnace with each charge of ore. However, as there are but few times when one adjusts himself to these Instruction s as he should, it is well to keep in mind the following Warnings: When ores of Sulphur and Antimony are undergoing a roast and cease to give off bad Odours, it is a sign that the Sulphur and Antimony are driven off. Those ores which abound in carbonaceous matter will, at the beginning of the roast, give off a thick black Smoke, 120

[il

FlJ.'JDACIĂ“N JUANELO TURRIANO

BOOK II

ยก

ยก >

121

a s1gn that this which, by gett ing thin ner and whit er, 1s lnco nven ienc e has been disposed of. of the Lus tre The chan ging of Colour by an ore, the loss ing from N egrillo which it had befo re roasting, and the turn in sign that the (Sulphide) to Paco (Oxide) is a mos t certa ugh ther e is a ore is well disposed towa rds Quicksilver, altho very grea t latit ude in this. es), if they The ores which cont ain Cop pera s (Sul phat by wash ing the mus t be roas ted, are cleaned of it first that cont ain Cop grou nd ore, as has been said before. Ores highly coloured in pera s whe n char ged into the furnace rema alone will see this afte r roas ting ; he who roas ts Cop pera s chan ge of colour with his own eyes. ksilver comOn testi ng a little of the pulp , if the Quic , heat the Cop per mences to foul, it is a sign that , with the Sulp hur (also a and lron cont aine d in the ores, mixed with being conv erted com pani on of Anti mon y and Pyri te) are more Copperas. into Cop pera s. The longer the roas t the ace, a poun d, Whe n the char ge is removed from the furn Wat er is pour ed oras muc h as one may desire, is set apar t. of thre e or four on it to a dept h equa l to the thick ness e at once. 1f the Fingers. Stir sligh tly and allow to settl changes the colour wate r turn s whit e, or stain s the N ails or Silver has been of a tape whe n put into it, it is a sign that the k down and be calcined (mad e soluble) and that it will brea r in sorne vitri dissolved in wate r like Salt. Put this wate time s unti l the e fied vessel and wash the ore two or thre the Silver which wash wate r is no longer clou dy and all Eva pora te over a may have been calcined is gott en out. d, and may be slow fire, and all the Silver will be recovere wate r into which utilized by melt ing the residue. lf the s of havi ng soluble the hot ore was thro wn does not give sign s the colour of Silver, put a little clean lron in it. lf it take per Sulp hate ). Cop per, it cont ains muc h Cop pera s (Cop s is elim inate d Was h the ore as indi cate d, unti l the Cop pera Wat ers, as they and the lron is no longer stain ed. Save the ores which need may late r be utilized in the trea tme nt of FU;-.;DACIร N JCANE LO TURRI ANO

122

ARTE DE LOS METALES

Copperas. Now, if it be evaporated and the residue be melted, there will be obtained fine Copper, and the residue may contain sorne Silver, if any has been made soluble in the roast. Test on a small scale, by amalgamation, the ore thus conditioned, in the same way as was described for Paco (Oxides). Continue this testing until the experiments made show how the full-scale treatment can be carried out well enough to obtain all the Silver that the fire assay indicates. Judge non e of these Experiments as partaking of unnecessary and prolix Curiosity, because there is in this matter of ore treatment nothing more important and beneficia} [Than the preliminary tests.- Translators], though nothing more commonly ignored. After a few days of care and work, the amalgamator will recognize the kinds and qualities of the Ores he handles, and will know how to proceed with them, without repeating the Annoyances of so many tests. But, with all the aforesaid, the ore never arrives at the stage of being perfectly conditioned, so long as the little or much Silver contained is not purified and brightened in the pulp, before charging the Quicksilver. It is not possible to bring it to this state, because ores with a little Lead may be reduced through the roasting alone, while the Black Ores, and others, through their Sulphur fumes will film the Silver also, although this latter is only arrived at by prolonged roasting. In one way or another, by cookings and working over with reagents such as Alum, Salt and other substances, Silver may be cleaned and brightened. The ore being in this condition, Quicksilver needs no added reagent, and not more than four days will be needed to recover all the SĂlver. Moreover, there will be but little consumption of Quicksilver, because of the short period of treatment and the lack of excessive mixing and working over of the charge, which breaks up and Hours the Mercury; this Houring is the principal reason for loss of quicksilver, as will be seen shortly. FUJ\DACIĂ“N JCANELO TURRIANO

l 11 ยก'

lยก

CHA PTE R FOU RTE EN THE NAT URE OF QUICK_SILVER

Tim e will Leav ing for anot her Occasion (which perh aps ksilver and gran t) the more detai led desc ripti on of Quic , I shall, with there sorne com mon but useful Expe rime nts of the nix Phoe for the pres ent, touc h but light ly on this " followed by Sciences. Raym ond, in his "Inte llect ual Art, ores, thou gh t of y soph all the believers of the occu lt Philo e so uniform, that N ature crea ted this body out of a subs tanc even Fire, its and of parts so perfe ctly unite d, that not ), has power to grea test oppo nent . (as is vulg arly imag ined visibly is able it divide, corr upt and destr oy Quicksilver, as ld, aside from to do with ores and othe r bodies of the Wor agai nst Fire if Gold and Silver. Quicksilver will be proo f discovered been it is give n the prop er conditions, which have Or, with the by seve ral Persons, and sorne know n by me. enco unte ring Fire, it will flee as a sort of Vapo ur, which, its original to again sorne body to cool it, will be condensed ht. Not even form, with out the least loss of its form er weig arily occu rring the E vil Subs tanc es, men tione d before as ordin ama lgam ation the with the Ores in their Veins and with tly. Alth ough charges, can corr upt Quic ksilv er perm anen and Salt, may Copp eras, whe n subli med with Quic ksilv er to cons ume seem to flour the Quic ksilv er in such a way as anot her suband total ly dest roy it, by conv ertin g it into imat e), this stanc e which -we call Solimรกn (Corrosive Subl All these accidestr uctio n does not in reali ty take place. nor even very e, dent s have a Rem edy, and it is not impossibl ed Quicksilver. difficult, to revive and reun ite the flour prop er place. The man ner of doing this will be show n in its 123

FUNDACIร N JCANE LO TURRLANO

CHAPTE R FIFTEE N WHICH TREATS OF THAT SUBSTANCE CALLED LIS [FLOURED QUICKSI LVER.-TR ANSLATO RS] AND OF THE DIFFERENT KINDS THEREOF

Broken up and very finely divided Quicksilver is commonly called Lis by amalgam ators. It is seen as a fringe in the horn-spoo n when ore is being tested; and from it experienced amalgam ators obtain an indication of the quality of the Ore and the condition of the charges being amalgamated. Flouring is caused by too long grinding of Quicksilver with the charge (a thing inexcusable in ordinary treatment), even if the ores contain no Evil Substanc e whatsoever. Of the Evil Substanc es, Copperas (as has been said) flours Quicksilver to a very great extent. When Quicksilver has not been affected by any foreign substance , but is simply broken down to a white flour, it is called Lis of Quicksilver; the floured Quicksilver made in grinding with Tin and Lead ores is called Lis of the corresponding metal. Lis of Silver is very finely ground Silver which, although it is covered with Quicksilver is not yet so thorough ly amalgam ated as to form what is called Pella (Amalgam ). Quicksilver takes unto itself various Colours, and they ' are shown in the Lises (the floured Quicksilver) according to the different things which accompan y the Silver ores into which it is charged. These can be reduced to three classes, which embrace severa! subdivisions, the three classes being Clear, Leady and F ouled. Quicksilv er shows Clear either when the ore has no Silver, or when the Silver which the ore contains is of the purest, without any interferin g element, or mixture of Base Metal. In this case the Quicksilv er will take up and absorb the Silver without losing its lively colour. 124

[il -

, FU~DACION

JCANELO TURRIANO

BOOK II

125

continues to Whe n the colour becomes leady, and the ore gam film is give indic ation of sorne Silver, unless the amal . Thes e have false, it is due to certa in causes and principies gam ation , in been given but little consideration in amal h of the hapwhich, up to this time , there has been muc · haza rd. er, gives Copp eras alone, the Arch-enemy of Quicksilv gam film .the colo urwh ich is called Plomo Falso [False amal er also carry Translators]. Like othe r ores, thos e of Copp mean eithe r to rrosa Copp eras. [Not e that Barb a uses Capa othe r Lead iron or copp er sulp hate .- Translators.] The use ordinarily coloured films are a certa in sign of Silver, beca rs of a baser othe with it is bego tten in crud e ores and mixed the Silver, f sort. The Quicksilver, attra cting unto itsel nying mixed carries along at the same time the accompa is the foundametals which give the unus ual Colour. This welve of this T tion for the previous state men t in Cha pter that the dark , Book, and the Reason by which one knows ksilver, or inclining to Black, Colour of the floured Quic . If the Iron ixed Quicksilver itself, proceeds from the adm -coloured, it is Quicksilver flour, or Quicksilver itself, is Lead clear, by accompanied by Lead . If it is some what more nied by mpa acco is Tin, and if inclined to be golden it Copp er. er, Base Whe ther the flouring is due to foul Quicksilv Quickof flour The Meta l, or Silver is easily recognized. life; out with silver alone shows itsel f as very fine, whit e and Quicksilver on washing clown the pulp in the horn-spoon, the were stuc k it gh thou does not run, but remains behind as it will run r to the botto m; if it is stirr ed up with the finge Floured Silver toge ther in Grai ns of lively Quicksilver. rding to the ama lgam shines like Filings, coarse or fine, acco m of the botto richness of the ore; it runs or rolls on the the finger, it horn-spoon behind the sand ; stirr ed up with ed amalgam consolidates into an amal gam hall. The flour consolidated of Base Met al may be between the two; when er. thro ugh stirring, it resembles fouled Quicksilv FUNDACIÓN JUANELO TURRIANO

CHAPTER SIXTEEN WHETHER ALL THE QUICKSILVER AND ORE SHOULD BE CHARGED TOGETHER

Having duly conditioned the ore, ascertained the Silver content of the charge, and the quality and quantity of the Reagents and Quicksilver needed, the amalgamator may still be in doubt whether he should put all the Quicksilver and Reagents at once into the Charge, in order to secure the suitable proportion of three parts of Amalgam to one of Quicksilver when he makes the clean-up. It is the opinion of sorne that it is best to throw all the Quicksilver into the charge at the beginning, and everyone followed this practice up to twenty Y ears ago. At that time I went to the Province of Los Lipes, where I used, and persuaded others to use, a different practice, being influenced thereto by smiliar work of Raymond which clearly concorded with Common Sense. Little by little, softly and without haste or violence, all things grow and are perfected. A little Fire is enough to heat the whole World, if the fuel is applied little by little, according to its heat-giving power; but if, at the beginning, all the wood is piled on, the Fire will be smothered and quenched. The natural body-heat of Animals is subject to the same inconvenience s, and proportionally the same thing happens in the treatment of amalgamation charges, because whatever may accidentally cool will slow clown the Treatment, and whatever may cause heat will hasten it. In addition to this, if the charge has not been handled well (and approximately as the Ores require) it may be lost and the Quicksilver floured. The thicker the Charge the easier: the remedy; if the Charge has to be brought back with Tin 126

[il -

FUNDACIĂ“N JCANELO TURRIANO

BOOK II

127

or Lead (which must be used as amalg ams.- Translators), the thicke r charge allows it to be done with less risk. Equal or greate r slowing down and d;¡tmage will follow if an Excess of reagen ts is added to the ores which may need them. Throu gh this Excess the Quicksilver may be sickened and may take up no Silver whatso ever; with difficulty only can the charge then be brough t back to th~ necessary condition, after many expensive delays and doctorings. Theref ore, mix with the Charg e only one-th ird of the total Quicksilver [which the small scale test has shown to be needed .-Tran slator s], and, at the beginning only one-ha lf of the Tin and Lead amalg am which m ay be needed. In this way the Quicksilver will take up the Silver quickly, and it can soon be recovered befo re all the reagents are spent: this happe ning is called "Load ing-up .'' By thus hasten ing the amalg amatio n, one may avoid the loss of Silver due to dry Amalg am being floated up in the pulp, occasioning great loss. Contin ue to add Quicksilver and Base Metal amalg am to the Charg e, as it may be needed, but diminishing them propor tionall y, so that the amalg am is at no time wet. In this way there is not much flouring, and the amalg am itself is an elemen t in the recove ry of the rest of the Silver, makin g the treatm ent surer and shorter. If the or-e has to be treate d with Lime, the rule for using reagen ts does not hold good. In the case of amalg amatio n • with Lime, put in all the charge at once, and work over very well two or three days befare adding the Quicksilver, being very careful not to have an Excess of this materi al, because Quicksilver, if it has unnecessarily been contam inated , with difficulty takes up Silver, and is harder to recover from the charges.

FUNDACIÓN JCANELO TURRJANO

CHAPTER SEVENTEEN THE WORKING OVER OF THE CHARGES AND THE EFFECTS THEREFROM

The first and principal Object of working over the Charge is to distribute the Quicksilver in the ore so that all particles of it may pick up Silver. Also, the Heat caused by moving the Charge tends to put it in better condition. Lastly, by the F riction the Silver is purified and cleaned: this is called "Grinding-in." The working over is a most necessary and important part of all ordinary Amalgamation practice; nevertheless, there have resulted many millions of inexcusable loss in Quicksilver consumption, due to excessive grinding when amalgamating. The Quicksilver is squeezed to such an extent between the fine and coarse Sand that it is divided into very fine particles (being then called Lis); in this condition, remaining as it does without weight or body, when the Charge is washed it does not go to the bottom of the clean-up tub. lnstead, it is drowned to such an extent, and mixed with the slimes, that it flows off with the wash water. This damage can be prevented, to a great extent, by two Precautions. T o begin with, the first and second day, there should only be two gentle Grindings, so that the Quicksilver is disseminated but not floured, because before the Silver amalgam begins to form the Quicksilver is more disposed to break up unduly. The Second Precaution is always to carry on the amalgamation so as to have the Amalgam dry, and not with an excess of Quicksilver or wet Amalgam. Add the Quicksilver little by little as may be necessary, and in this way, the Quicksilver and dry amalgam will be, at the most, in the Proportion of one of the former to two of the latter. Nor should any one deceive himselfi 128

. FUNDACION JCANELO TURRIANO

BOOK 11

129

thinking that when there is an excess of Silver, and so long as there is a sufficient quantity of the reagents, the trouble will not happen. lt may even come to pass that there will be a greater Loss through flouring dueto excessive grinding, and the possibility of consuming all the reagents; then there will remain behind only the Quicksilver, floured and sickened by the reagents themselves. On further grinding, this sickened amalgam is only lost. With finely-divided Silver there is not this risk, because the grindings do not waste nor consume it, but rather purify it more, so that it the better embraces and is united with the Quicksilver.

FUNDACIĂ“N JCANELO TURRIANO

CHAPTER EIGHTEEN MISHAPS WHICH MAY OCCUR IN AMALGAMATION, AND THEIR REMEDIES

Various are the Accidents which may happen to the charges in the course of amalgamation. The subject of all of them is the Quicksilver which alone we take into account, because it, as a Mirror, reflects the good or bad condition of the charge. The charge in itself, owing to the fineness of the Sand to which it has been reduced, and the mixture of the Earth with which the Silver was begotten, is not so easily judged by a visual examination. If the Quicksilver is very much sickened, owing to the presence of an excess of such reagents as Lead, Tin, Iron or Lime, the globules will be flattened, or even elongated and like unto a Worm, instead of being round. If shaken around in the horn-spoon without water, the sickened globules will tail out and stick to the spoon. In this condition its Activity is lessened and the recovery of the Silver is impeded. By the force of much working over, this Damage can be remedied, but at much cost and loss of time. The quickest and most efficacious remedy is Copper Sulphate, or that solution thereof which I advised, in Chapter Thirteen of this treatise, should be recovered and set aside. Add Copper Sulphate water to the charges when they are reworked, more or less, according to the fouling of the Quicksilver, and the almost instantaneous Effect will be noted. The Reason is clear: as has been stated, Copper Sulphate dissolved in water, visibly and truly converts the base metals into Copper. And it is thus that they lose the Coldness which they formerly had, and which slowed up the Quicksilver, and take upon them the Heat which IS a 130

[il

FUNDACIĂ“N JUANELO TURRIANO

BOOK II

131

property of Copper and is the cause of the Quicksilver being livened up. On this is founded the beneficia! effect of ground Copper when put in the charge. Here it is to be noted that not all the ores of Copper, nor even the rich ores, are appropriate for cleaning up or making the Quicksilver fit for amalgamation ; solely those which abound in Verdigris or sulphate are usable. The Virtue encountered in the socalled Magistrales, used for their effect in heating and cleaning amalgamation charges, is due to the same Copper Sulphate, produced, as before mentioned, in the roasting. For the satisfaction of those who may desire to know, here are set clown the composition of sorne of the Magistrales: Roast Copper ore, and after it is ground and kneaded with an equal quantity of Salt, make into Bricks and roast agam. Another: T o two parts of Copper ore add one part of Salt, and no more; knead together and roast. To one hundred pounds of this powder add eight ounces of Brass filings. Another Magistral is m a de from slimes, sand tailings and salt, by third parts, well roasted. Another from Copper ore, sand tailings and salt by third parts, all well roasted. Another can be made from sand tailings of the ore being treated, and salt, equal parts [To be roasted?-Tran slators]. Another may be prepared from Copper ore, sand tailings, sorne of the ore to be treated, finely ground, Iron slag, and salt, equal parts all kneaded together, made into Bricks and ro asted. Another is made from three parts of roasted slimes and one of salt. However, everyone invents such Mixtures and proportions them in his own fashion, and as he finds best. The foundation of all Magistrales, as has been said, is Copper Sulphate, produced in the roasting. This may be seen by anyone who will follow the Instructions given, and the result seems to confirm Pliny's statement, that Copper was begotten by ro asted Stones. One should use these M agisFUNDACIĂ“N JCANELO TURRIANO

132

ARTE DE LOS METALES

trales with the same circumspection as the other reagents mentioned. Before mixing up the charge, preliminary tests must be made to ascertain the proportional amount of reagents to be added; beca use if there is an excess of reagents there arises another dangerous condition, described as follows:

FUNDACIĂ“N JUANELO TURRIANO

CHAP TER NINET EEN WHICH CONTINUES WITH THE SUBJECT OF THE LAST CHAPTER

An acciden t opposed to that mentio ned in the last Chapte r, and which is a source of great Quicksilver loss, is excessive Flourin g, that is to say, the conditi on in which no Amalg am forms. Greate r still is the damage if this excessive Flourin g is due to Copper Sulpha te, as there will then be much scatter ed Quicks ilver in very round and lively Particle s which keep separat e from the amalga m. These particle s do not beco me elongat ed if divided ; rather all parts assume spheric al forms, althol{~h very small. One remedies this trouble with contrar y reagent s,which will, as said before, liven the Quicksilver. lron has this particu lar virtue, attracti on and natural sympat hy, and is most approp riate to reunite and give body to the scattere d and almost corrupt ed Quicksilver. The manne r of using it will be treated more fully hereaft er, when the washin g of the charge [Cleanup.-Tra nslator s] is considered. N o certain rule can be given in regard to the q uantity of reagent s to be used to correct charges which have gone off, because neither the effects nor the causes are always the same. Howev er, it is better,. in general, not to work over the charge until the Amalg amator has ascerta ined from small scale tests what is necessary. Set apart at once a third or fourth part of the charge, and in it alone charge all the reagent s and work over until they are very well divided and incorpo rated. This part will then be mixed and well worked over with the rest. In this way the reagent s will be better and more uniform ly mixed, especially if the quantit y to be added is small. Be careful to follow the treatm ent 133

FtmDACIĂ“ N Jt.:ANELO TURRIANO

134

ARTE DE LOS METALES

found necessary, so as not to give place, Firstly, to undue fouling of the Quicksilver; Secondly, when remedyin g the fouling, do not add such an excess of Copper Sulphate as to flour the Quicksilver. If, on testing the charge with the horn-spoon, it is found that the Quicksilver is in little Globules, or divided into Grains, and will not unite, it is a sign that the amalgam ation is not coming on well. That which is like a Shell or Film around the Globules of Quicksilver does not permit them to unite. The lack of reagents a:Ione may cause this. Sometimes the condition can be remedied by adding Base Metal amalgam , or roasted Tailings (which by their acidity aid in cleaning the Quicksilver), or by continued Grinding. Sorne throw in Ashes, but the true and natural remedy is Salt, and that substance called Millo or Alum, used to brighten Silver. There is ordinarily an abundanc e of this in mining Districts. It is not lacking here, in PotosĂ, in Guaco de Santiago, an Arroyo where this alum water continual ly flows. When the charges are not uniformly worked over, or the Quicksilver is not added when necessary, or when the pieces of amalgam fail to go together, the amalgam is said to be dry. In the tests with the horn-spoon it will be found in curly pieces, and if the trouble is not remedied befare the charge is washed, the amalgam will remain in the charge and go off with the slimes, with great loss to the owner of the ore. It is not wise to try to recover dry and floured amalgam until the charge is ready to clean up; it can then be done by adding an excess of Quicksilver. W et silver amalgam is al so very good, if added to the charge and worked in just befare the clean-up.

FUNDACIĂ“N JCANELO TURRIANO

CHAPTER TWENTY HOW TO DETERMINE WHEN THE CHARGE IS READY FOR THE CLEAN-UP

There is no fixed Period after which the charges should be washed, or cleaned up. Their ripening is hastened by too much Grinding, the exterior heat of the Climate or Weather, and the interior heat derived from the Copper, or Copper Sulphate, and other substances which partake of their virtues in cleaning and purifying the Silver. The roasting of the ores is also an important factor. On the contrary, the treatment will be prolonged if the number of workings over are not sufficient; and the same thing happens if it is freezing Weather, if the charge is overworked, or if the Quicksilver does not keep bright. One arrives finally (after overcoming these and other Troubles) at the point of taking out the clean Silver mixed with Quicksilver; the operation of separating it from that which is earth is called Washing. Not a little Knowledge is necessary to be able to tell when this stage has been reached; because, if it be not reached, one loses the Silver which has not yet been amalgamated. If the treatment is prolonged, the amalgam is ground up, and even if this is not carried too far, there is at least the loss of time and Silver due to excessive grinding, in addition to other risks. Subject to many grave Errors have been the rules employed up to the present for determining if the charge is ready to wash; if it is in good condition; if more Quick:silver is to be added; when the Silver has all been amalgamated; and whether the mass of Quicksilver and Sil ver is clean, and of a colour which inclines as much as possible to that of Gold. There are many other Troubles to be 135

FUNDACIĂ“N JCANELO TURRIANO

136

ARTE DE LOS METALES

watched for, all of which may cause further mishap. The infallible and certain Rule is to determine if the Quicksilver has taken up all the Silver which the fire assay, made at the beginning, showed the charge to contain. If this re.mlt has not been attained, halt the work, but do not wash the charge. F urther small-scale amalgamation tests should then be made on the charge, and from the experiments one will recognize the trouble or what is lacking, and thus the remedy may be applied and the final point arrived at. Being ready to wash, the amalgam being dry and in the aforesaid proportion of Quicksilver and amalgam, sorne fresh Quicksilver should be charged and worked over gently two or three times. In this way the charge should go to the tub with a proportion of three parts of Amalgam to two parts of Quicksilver; or, at least one of Quicksilver and two of Amalgam; thus, sorne of the floured Quicksilver, as well as unamalgamated Silver, will be recovered, and the greater volume of Amalgam will sink the more readily in the cleanup tub, obviating the loss from suspended Amalgam. When the clean-up is begun, charge sorne fresh Quicksilver into the vessel called a clean-up tub. Stir well into the Quicksilver and Amalgam of the charge; this will help the recovery, and the more there is added the lower the loss of dry amalgam flake.

FlF.\IDACIĂ“N JCANELO TURRIANO

CHAPT ER TWENT Y-ONE WHICH SHOWS THAT IN WASHING THE CHARGES ONE CAUSES A LOSS OF QUICKSILVER

All the troubles which have been experienced, and are experienced to-day, through what is called Consum ption and Shortag e of Quicksilver, take place in the clean-up. Up to this point there is nothing lost, and one's Sight deceives if he judges otherwise, even on the occasions which have arisen, and may again arise, when neither Quicksilver nor Amalga m is recovered from the ore with which it was mixed. Not only are these accidents which alter, but do not corrupt or cause loss of body to the Quicksilver; in the charge, even when it is in more or less good condition, the Quicksi lver may to- go out imperce ptibly with the Water and Slimes. The immedia te cause of this damage is the excessive Fineness, and (one may almost say) lack of body and weight, without which the floured Quicksilver will not sink to the bottom of the charge. Rather, on washing, because of the stirring, the floured Quicksilver is entangle d and flows off in the slimy water. Afterwa rd there is a shortage of the Quicksilver originally charged, conforming more or less to the greater or lesser grinding and abundan ce of floured Quicksilver. Grossly have they erred who, self-persuaded, believe that, in the ·amalga mation of Ore, Quicksilver is truly consumed, holding as suflicient proof, and the stronges t reason for their belief, their Experie nce in ore treatme nt over many years in this Kingdom. Here the best trained of amalgam ators has consume d as much Quicksilver as the Silver he has recovere d; and he has not perceived that he is deceived by the very things his hands touch. The missing Quicksilver 137

FUNDACIÓN JL:ANELO TURRIANO

138

ARTE DE LOS METALES

and amalgam remain in the Sands and Slimes, as the owners of the ores know to their sorrow. Of frequent occurrence in these Provinces are the fortunate Discoveries of those who huy Tailings. Others, speaking as Philosophers, attribute the consumption to a Debility which appears in the Quicksilver when it is occupied in attracting Silver, as happens with other things in N ature. They would ha ve proven something if, at the same time, they had shown that Contrariness of Qualities, which would be necessary for this reaction between Quicksilver, Silver and like Metals. It is the aim of all these to attribute, not only to Silver, but to the accompanying ores as well, this opposing quality which destroys Quicksilver. However, they can neither prove the cause, nor show to be true the imagined Consumption of Quicksilver due to this so-called Debility. Such does not exist, and definite experience proves the contrary. The most completely lost and broken-down charge can be brought back, and all Quicksilver recovered, by the method which will be explained hereafter.

fl))IDACIĂ“N JlCANELO TURRIANO

CHAPT ER TWENT Y-TWO THE LOSS OF QUICKSILVER AND THE REMEDI ES THEREF OR

The grinding togethe r of the charge and Quicksilver is one of the lesser causes of the losses of Quicksilver, because of the squeezing and dividing action, resulting in particles called Flour. With whatsoe ver . Ore, Earth or Sand the Quicksilver is charged and ground, there will be the said effect, greater with the Galenas, Pyrite, and Steel-coloured ores, which, by their weight and glassiness (for it is thus we call it) more easily cut and break up the Quicksilver. Copper Sulphat e, by its nature, as has been said at various times, aids violentl y in this breaking up of the Quicksilver, and has been the cause of the greater part of the losses. Among the contribu ting causes of Quicksilver loss is Salt, used in amalgam ation and the clean-up, because, as all know, it increases the density of the Water, so that not only the floured Quicksilver of but little Weight, but even things of greater Weight may be suspended, and not go to the bottom. The Slimes, which are mixed in this Water and make it turbid, increase the density, and more easily suspend the Quicksilver, allowing it to go off and be lost thei:-ewith. And lastly, there is the moveme nt of the stirrer during the washing, which also prevents the floured Quicksilver from sinking, thus augmen ting the aforesaid Evils by its inclinati on to keep the particles suspended. This is certain and patent to all. The ordinary grinding in this class of treatme nt cannot be eliminat ed, but, if the aforesaid Warning s are heeded, it will be less harmful . Also there has been shown a way to remove Copper Sulphat e from ores, and to overcome the 139

~ FUNDACIĂ“N JCANELO TURRIANO

140

ARTE DE LOS METALES

refractory character of Pyrite, Galena and the Steel-coloured ores. Salt may be recovered from the charges with two advantages: the lessening of Quicksilver loss, and the saving of this reagent, for which a great many ducats are spent annually. Treat the ore in Boxes, of the type ordinarily used, closed on all four sides. Let the bottom slope slightly, but no more than necessary, so that the water will run to a common point. At this point let there be a Hole, ordinarily closed, through which at the proper time the water can be let out. When the charge is to be washed, run on water in abundance, and open up the pulp in many places with a Hoe to secure a better penetration of the water. At the end of a short period of this mixing, open the hole and allow the water to escape, carrying with it no small part of the Salt contained in the charge. Save this Liquor in a suitable vessel, where it may either be allowed to crystallize, or it may serve again for treating charges. Wash two or three times, until the water which comes off no longer has the taste of Salt. If the charge has to be washed three times, it is better to wash it six times, whereby the water will be less slimy and twice as easily clarified. The stirrer should not always be kept in the same position, because, if this be done, the fine particles of Quicksilver or unamalgamated Silver will always move in parallel Circles, at equal distances; they will not come together, nor will they unite, the one with the other, to make more body and thus sink to the bottom. At every fourth or sixth Revolution the stirrer should be shifted a certain amount. However, as this cannot be done in the ordinary clean-up tub, insert a Baffie, which will oppose the movement caused by the stirrer, thus disturbing the Course followed by the floured Quicksilver and unamalgamated Silver, causing them to find one another and become united. The stirrer and all the tub (except the bottom, which does not need it on account of the Quicksilver FUNDACIĂ“N JUANELO TURRIANO

BOOK II

141

bath) is covered with amalgamated sheets of Copper or Iron. In this way whatsoever part of floured Quicksilver may come against the sheets will stick and be held there. On washing the charge, the Quicksilver and Amalgam are easily removed and scraped together with a piece of soleleather, felt or cloth.

Flf.\DACIĂ“N JCANELO TURRIANO

CHAPTE R TWENT Y-THRE E SQUEEZING AND RETORTING THE AMALGAM

1¡

1•

1! 1

After the Qmcksilv er and Amalgam are taken out of the tub, they are squeezed in a double cloth, wetted in warm water, in order to remove the excess Quicksilv er. One may assist this removal by blows from Paddles, so that as much Quicksilv er as possible may be separated from the Silver. Put the amalgam into the customar y Moulds, which, because of their pyramida l Shape are called Piñas (Pine Apples). The Silver yield is approxim ately one-fifth of the amalgam. F or example: from one hundred pounds of amalgam there will be obtained forty marks (three hundred and twenty ounces) of Silver. The yield of Silver in amalgam of rich ores is inclined to be less than in that of poor ores, because the Silver of the former is more spongy, and the Silver of the latter finer and denser. Even when the greatest care is taken, sorne of the Sil ver amalgam passes the cloth when it is squeezed. The wetter the amalgam the more of it will pass. In the case of water mixed with mud one sees a similar thing. E ven with the greatest care in pouring off the water, it will not continue to be clear and pure, but will be made turbid by the mixture of Slimes it carries. The more water poured off, the more the mud with it. Allowed to rest and settle, the mud assumes body and separates from the clear water. The same thing happens to Quicksilv er which has been squeezed out of amalgam and left to settle in the boxes or tubs. At the end of sorne days a quantity of Silver amalgam settles out. I myself saw in the Santa Catalina Ingenio (Mill), in Los Lipes, a considera ble quantity of amalgam recovered from the bo~tom of a Quicksilv er tank. 142

FUNDACIÓN JCANELO TURRIANO

BOOK II

143

If the Quicksilver is heated, more of the amalgam, and therefor e more of the Silver, will pass through on squeezing. F or this reason, when the hot amalgam from pan amalgamation is squeezed, even with much care, Silver will pass through the cloth. If the Quicksilver is strained again the following day, after cooling and setting, addition al amalgam will be obtained . Very great, and without any Excuse whatsoever, has been the loss of Quicksilver in retorting . Notwith standing the low cost of treating ores to-day in this Imperia l Village, the yearly retorting loss alone amounts to at least 30,000 Pesos. Thus can be conjectu red the sum that has been lost in the amalgam ation of the rich and abundan t ores of this and other mining camps of the Kingdom. This loss proceeded (and still proceeds) from the lack of care in selecting the Materia l from which the pipes and retorts are made, as well as from the little diligence that is used in luting the retorts and condensers. The Clay from which they are commonly made is very spongy and full of pores, so that water will pass through and sweat out on them. Thus it is no marvel that the Quicksilver, converte d into a dense vapour (and in a fine state of division due to the Fire, which has also expande d the pores of the retort), penetrat es the vessels and is lost. T o say that sorne part of the Quicksilver itself is corrupted by the force of the Fire is purely the Imagina tion of those who have little Knowledge of the uniform ity of this substanc e, as said before. Make the retorts and pipes ftom that clay used for crucibles, and the trouble will cease. The retort thus made will be a lasting work, owing to the quantity it will condense and the way it will resist the fire. If by mischance it should receive a strong Blow, it will not break. In that noted village of San Felipe de Austria de Oruro (Oruro of to-day) famous for the Gold and Silver veins which enrich it, there is a vein of White Earth, in a small hill above the Church of the Rancheria. From this vein is obtained a FIDIDACIĂ“N JUANELO TURRIANO

144

ARTE DE LOS METALES

Clay so tough and dense that, .after burning, it is not surpassed by the finest of China-ware. I experimented with -and publicly advocated the use of this for Crucibles, with no small benefit to those who had need of them. U p to the present, because of the little Time at my disposal and my many T asks, I have not been able :to find a similar Clay in this Village (Potosí), but I do not doubt that it exists. Potosí, in her abundance of the Riches of N ature, has never lacked ·the means to augment the Splendour and Renown of her ores. But, when and where good Clay is lacking, mix the best attainable with lron scale or Slag finely ground. Pug the Clay well and make the retort. Burn it very carefully, and it will be found to serve with less risk of damage than those ordinarily used. lt will be well to vitrify the inside of the pipes, but the retort should not be vitrified, because the violence of the heat will crack off or fuse the glaze.

Fl];\;DACIÓN JCANELO TURRIANO

CHAP TER TWEN TY-FO UR OTHER AND SURER METHODS FOR RETORTING AMALGAM

The best retorts are made from beaten Iron or Coppe r sheets, no thicke r, or someth ing less, than a Real (about one-eighth of an inch). For greate r security, and in order that the retorts may last the longer in the Fire, it will be best to apply outsid e a close-fitting coat of good Clay. Not many years ago, a few commenced to make these vessels of cast Brass, but for a good reason they ceased. They had heard somet hing about the use of metallic retorts , but they erred in the Execution, lacking a knowledge of the principies. The same thing happen ed, in the Province of Chichas, to those who tried using cast Brass cauldrons for amalg amatin g, after many had seen and others had heard of my work in Los Lipes, the neighbouring Province. In the next book will be shown the cause of these errors. The best, quickest, and safest way to retort is the following: Make the bottom of the retort of Iron, and of size sufficient to accommodate the desired numbe r of amalg am cakes. Let the retort be wider above than below. Set it on grate-b ars of strong Clay, or bar-iron, in a little furnace of sufficient capaci ty, so that it can be heated with Wood or Charcoal, whichever is conven ient, throug h a suitab le firing-door. Every where else, below, above, and on the sides, it should be closed, except for a suitab ly located Smoke-hqle. The retort will then be so fitted in the furnace opening as to projec t one or two finger-thicknesses above the furnace structu re. Placed thus, it fits into and joins with anothe r vessel which serves as a condenser. Charg e the amalg am on the bottom of the retort, well spread and packed, or made into balls, as may be desired. So that the Silver, even if it melts, may not stick, the retort should first be coated with a wash of fine Ashes or Clay. 145

FUNDACIĂ“N JCANELO TURRIANO

146

ARTE DE LOS METALES

Close with a piece like the head of a good-sized alembic, made from beaten Iron or Copper, or of very well vitrified Clay. Let it have a long neck, which, at the small outlet, will admit a finger. Mud the joints well. In a safe place, and where it will not feel the heat of the furnace, locate a

vessel of Stone or other material, full of cold water; let the nose of the alembic enter the water to a depth of two fingerthicknesses. Light the fire in the furnace. Fleeing the fire, the Quicksilver, converted into vapour, will strike against the cool conical part of the head, and be reduced to FUXDACIĂ“N JCANELO TURRIANO

BOOK II

147

its original condition ; thence it will pass through the outlet of the alembic to the bottom of the said vessel. The alembic will be cooled frequentl y with wet cloths, and, if the water in which the Quicksilver is being caught should become unduly heated, it should be tempered with cold water. A-The iron vessel. B-Head of the alembic. CAlembic nose. D-Reto rt support. E-Pan or vessel filled with water in which the Quicksilver is collected. F-Furnace. G-Fire-d oor. H-Door for removing ashes. I--Opening in the setting, where the retort comes out and is joined to the condenser. K-The chimney through which smoke is carried off. It also provides draft for the fire. The annoyanc e of luting the joint of the amalgam pot (A) and condenser, and the risk therefrom , may be obviated by making the amalgam pot one palm and a half wider than usual. At a point inside, where the diameter corresponds to that of the ordinary condenser-head, fix a circular channel into which the condenser head will fit loosely. A little farther down than the point to which the condenser reaches, fix the stops or rests of what is called the candelabr a, or rack, upon which will be placed the holders for the amalgam. The candelab ra will reach up to a finger-thickness above the amalgam pot bottom. Let two small pipes enter and leave opposite points of the channel, to provide a constant flow of cold condensing water. These will not disturb the loose-fitting condenser head. The Quicksilver will thus be recovered without risk. If the amalgam is retorted in an alembic, the same result can be attained by soldering a channel ·of Copper to the mouth of the lower vessel, two finger-thicknesses in width and another two in depth; the alembic head will fit loosely into this channel. In this channel the alembic is so fixed, either by a weight or by tying down, that the force of the Mercury vapour may not lift it up. It may also be secured by a large Iron bar passed through the ring of the condense r head and fixed into small recesses built in the sides of the furnace for this purpose. FlNDACIÓN JCANELO TURRIANO

¡ ¡¡

FUl\'DACIÓN JCANELO TURRIANO 1

THIRD BOOK OF

EL ARTE

LOS METALES

IN WHICH IS DESCRIBED THE TREATMEN T OF THE ORES OF GOLD, SILVER AND COPPER BY COOKING (PAN AMALGAM ATION.-TRANSLATORS)

CHAPTER ONE HOW THIS METHOD OF TREATMEN T WAS DISCOVERED

In the year 1590, I was residing in Tatabuco, a town in the Province of Los Charcas, twenty-fou r miles from the city of La Plata, which is the capital of that Province. Having read of a method of solidifying Quicksilver in an Iron pot, or vessel, I desired, at that time, to experiment · therewith, and lacking the aforesaid Iron pot, I made the experiment in an ordinary Copper jar of small size. As I did not obtain the effect expected, I added at hazard sorne Substances , among them finely ground Silver ore, thinking that these ores might contain certain Virtues, which, aided by the Heat and Moisture of the cooking, would be of importance in my attempt. Briefl.y, at the end of the cooking I took out a quantity of Silver amalgam. At first, as would naturally be the case with one not experienced in this procedure, this confused me nota little. I soon became enlightened when I noted that what the Mercury had picked up was the Silver content of the ore, and no other substance which might have in part been transmuted . 149

Fl]},'DACIÓN JUANELO TURRIANO

150

li 11

ARTE DE LOS METALES

I remained very well content with this new and short Method for treating ores, which I had discovered through Chance. Since then, through Investigation and Experiments, carried on these many Y ears, I ha ve bettered it. I have used and publicly advertised it, making no Mystery thereof, neither reserving unto myself this nor other secrets. I ha ve used it more effi.ciently since the year 1615, when I was curate of Tiaguanaco in the Province of Pacajes, and, on a large scale and with more P'rofit, since 1617 in the Province of Los Lipes. After the lapse of so much time, sorne have attempted to gain for themselves the Gratitude belonging to another, and have 1ÂĄought advantageous premiums in different Parts as the inventors of this new treatment. Nevertheless, they have well demonstrated that they could neither recognize their own Mistakes, nor the Deceptions of others. As for myself, I know for certainty that neither did I learn it of anyone, nor did I ha ve any idea of it until the said occasion. The World is wide, and it may be that in sorne other Place, or at sorne other Time, this Process has been used before, although no mention whatsoever is made of it by ancient and modern Writers. The Real Audiencia de la Plata [The Crown's Executive Council.-Translators] conceded me a monopoly, and forebade the use of this Process except by license from me. Without compensation I have permitted all to use it, although I have reserved unto myself certain Details which will be noted in the succeeding Chapter.

FUNDACIĂ“N JUANELO TURRIANO

CHAPTE R TWO THE ANTIPATHIES AND SYMPATHIES WHICH EXIST BETWEEN ORES AND MINERAL SUBSTANCES, AS AMONG OTHER THINGS IN NATURE

Many are the Virtues and hidden Properties that God has placed in all the things of Nature; and the less known the Causes, the more marvellous seem the effects. It is in vain that the most subtile of Philosophers tires, and always will tire himself in investigations _and discourses on his Reasonings; since, to preserve the Majesty of Nature, and to humiliate overweening human Presumpt ion, the Author of all has hidden these things in obscurity. This human Presumpt ion, though unable to explain that which its own hands touch, nor that which its own eyes see, each day is intent on lifting itself above the Heavens, to solve by puny efforts the Immensi ty of the Divine Dispositions. While books are full of details about the Phenome na of N ature, and many are exceedingly well known, not even those accustomed to reason on hidden causes pass beyond vague Conjectu re. Antipath y and Sympath y, which are like unto Discord and Concord between one thing and another, they call the foundatio n of these marvellous effects. Most pleasing is the spectacle which Nature advances in the perpetua! Peace and inviolate Concord guarded by sorne things among themselves, and the capital Hatred and Enmity with which others seem to pursue and detest each other. This was assigned by Empedocles as the origin and seed-bed of all the E vil of the World. This Sympath y and this Antipath y are found among all other things, as well as among the Elements. Even unto the Heavens themselves the Astrologers have gone with their 151

FUNDACIĂ“N JL"ANELO TURRIANO

152

ARTE DE LOS METALES

friendships and enmities, pretending such between the Planets, as sung in elegant verses by Manilla, and as taught by all in the rudiments of the justiciaria. Equal marvels of N ature are seen daily in the behaviour of Plants and Animals. On this subject I could cover not a few pages, though I excuse myself on account of its being inappropriate. Between Stones and Metals no lesser marvels are to be observed; notable marvels produced by human intervention are the effects of the Magnet on Iron and the effect of that water called Fuerte (Nitric Acid), made from half-minerals, in which, as though it were Salt, Silver is dissolved and converted into a liquid, though any accompanying Gold will not be altered whatsoever by this violence. A contrary effect has the same water if in it is dissolved a little Salt; then the liquid converts the fine Gold into a Ruby-coloured liquid, leaving the Silver entire and without damage. Many are the other results obtained by those who work in these materials. Between the Metals themselves one finds the same Friendship and Enmity as between other things: of Lead, Tin alone is a friend; all others it ha tes and destroys. Iron, with a particular activity joins itself to Lead, and revives QuĂ?cksilver when already nearly lost by fouling. The Magnet [Precipitant.- Translators] of Silver is Copper, which, to the justifiable Admiration of those who see it, attracts unto itself dissolved Silver, and reduces it toa solid. This is an old experience in the World, and one which might have, long before this, opened the eyes of those who treat ores, as to how by this means they might the more surely and easily recover what Silver the ores contain.

FUNDACIĂ“N JCANELO TURRIANO

CHA PTER THR EE THE HOW WATER TAKES UNTO ITSELF THE QUALITIES OF ACT CONT IN S COME SUBSTANCES WITH WHICH IT

The substa nces suspended in water , or over which it may pass, comm unica te unto it their Qualities or Virtues. Thus as origin ate tastes , odours, and colour, greatl y differing, of ity divers the s, seen in the variou s Springs and Stream ntered natur al Baths , and the many medicinal Virtue s encou therei n. Andre s Baccio Elpid iano wrote a long, learned and of curious Treati se, called Thermis, on this subjec t; it is the it equal intere st to Philosophers and Physicians, and in reade r will find several references to Ores, or Metal s. Ores also impar t their qualities to water , and, althou gh it would seem that their Massiveness would be a hindra nce, such is not the case. More so is this true with the coloured [Oxid ized.- Translators] ores; in a short time the water e attrac ts and takes unto itself somet hing like a subtil eman ation of the ore with which it is in conta ct. Steelwater , known and used by Physicians, has been described by two learned Arabs , Avice nna and Raris, who say that the oftene r the red-ho t Steel is quenched, the more medicinal is the Virtu e impar ted to the water . In the Sixth Book of the said Elpid iano are described the curious and admir able effects worked by the water s of each of the Metal s in curing the huma n Body. These effects are , , confirmed by that very ancien t autho rity, Scribonio Largo al by Dioscorides and by Galen, throu gh their person experience. F urtl;er , presen t-day practi tioner s contin ue to use these medicinal water s. Elphs tadio, in his treati se on Philos ophy, testifies to this same effect, and describes this easy exper iment to prove it. Melt (so he says) Lead 153

Flli\DAC IĂ“N JUANELO TURRIANO

154

11'

ARTE DE LOS METALES

and throw in water. If now red-hot Iron or other metal is quenched in this water, it will become most docile and soft. On the contrary, if melted lead is· thrown a few times into water in which Iron, Gold, Copper, or other hard metal has been quenched, it will become harder. This is a certain sign of the qualities which one and the other impart to the waters, and receive from the metals, through heat. On this principie Marcillo Ficiño founded his reason for charging all the Learned Ones to keep secret and mysterious the Potable Gold, of the virtues of which many speak, in which sorne believe, and which exceeding few have experienced. On this mysterious Solubility also is founded the quick and eas·y treatment of the ores of Gold and Sil ver by cooking in Copper vessels; in vessels of clay, or other metal, the treatment is prolonged and nothing recovered. The virtue imparted to water by the Copper in which it is boiled livens the Quicksilver and cleans the Silver, so that it is easily picked up or amalgamated. Water which has been boiled in iron, films over Quicksilver and makes it torpid and useless. And, although water boiled in Copper is not itself suitable for recovering Silver, neither recovering, embracing nor atrracting it, through the Contrariness of the qualities of Copper imparted to it, the Quicksilver is aided in amalgamating the silver, as will be described in more Detail in the Chapters which follow.

FUNDACIÓN JCANELO TURRJANO

CHAP TER FOUR THE MATERIAL FROM WHICH SHOULD BE MADE THE CAULDRONS USED IN THE TREAT MENT OF ORES OF GOLD OR SILVER; AND ALSO THE SHAPE THEY SHOULD HAVE

Only of pure and very well refined Copper should be made the vessels and cauldro ns for treatin g ores by amalga mation . If there is any mixtur e of lron or Matte, in additio n to other inconve niences , the metal will be brittle, and cannot be worked with the hamme r. And if the sheets are alloyed with Lead, Tin, Silver, or Gold, substan ces with which the Quicks ilver will easily amalga mate, in a short time it will pass throug h and penetra te the bottom . When the Copper Ingot is cool, cut away all spongy metal, and beat the sheet from the salid part only. The vessels may be of whatso ever capacit y is desired, accordi ng to the quanti ty of the ore one may desire to treat most comfor tably as a single charge. The bottom should be in the forro of a frying- pan, more narrow below than above, flat and in one sale piece, up to six or eight finger-thicknesses in height at the least, and of the thickne ss of half a finger. On this bottom , and around it, there will be riveted sheets of Copper , wider at the top than at the bottom . The sheets will be half the thickne ss of the bottom, or, ĂŠven someth ing less will suffice. In these proportions the cauldro ns may be augmen ted for the size and quanti ty that may be desired. Rivet these sheets to the bottom , and to each other, with well-tig htened Copper rivets. When the necessa ry height is attaine d, finish off with a rim of Copper or Iron, as is custom ary among Copper smiths. Attach two strong upright Lugs in which, as will 155

FUNDACIĂ“N JL:ANELO TURRIANO

156

ARTE DE LOS METALES

at once be explained, there has to be fixed the bridge of the Stirrer. For greater security, apply to the outside joints a paste of Quicklime or Ash, kneaded with Bull's Blood, so that neither water, ore slimes, nor Quicksilver can get through. Make a Stirrer of the ordinary pattern, although not of such heavy timber. Less strength is needed, on account of the aid from the boiling, the fineness of the Sand, and the great amount of water that must be mixed with the ore.

o ra~

The die on which the Stirrer moves must be made from Bronze. Attach the die to a Copper strip, two finger thicknesses wide and one-half in thickness, and as long as the diameter of the cauldron. The strip should be well adjusted to the bottom, fairly tightly, so that it will not shift. The ploughs of the Stirrer do not need to be equal in length; those nearer the centre may be longer, and those nearer the circumference shorter, as may be judged best by sight, according to the proportional width of the cauldron. Fix the bridge in the two lugs with. Wedges. FUNDACIĂ“N JCANELO TURRIANO

BOOK III

157

The crank may be turned by a fairly long wooden Sweep fitted with an iron ring to drop over the end of the Stirrer shaft above the crank; thus the cauldron can be stirred from the outside. Even if the cauldron is wide, and the heat from boiling water very great, it can cause no inconvenience. The rest of the Stirrer is of the same construction as used in ordinary clean-up tubs. A-The one-piece bottom. B-Cauldron built up from sheets. C-Lugs. D-Stirrer. E-One of the four arms with ploughs of unequallength. F-Sheet from which the cauldron is built up. G-Copper strip with die, on which the Stirrer rests. H-The die. I-Stirrer bridge. K-Roles for the lugs. L-Hole for Stirrer shaft. M-Crank. N-Iron ring, and 0-Wood sweep for turning the crank.

FIDIDACIĂ“N JCANELO TURRIANO

CHAPT ER FIVE WHAT ORES ARE BEST SUITED FOR TREATM ENT BY COOKING (PAN AMALGAMATION)

By heeding the Warning s given here, any class of ore may be treated in the copper cauldron . Those which more quickly and easily give up their values are oxidized ores, mixture s of oxides and sulphide s, silver halides, and native Silver. Such ores need no reagents , nor prepara tion whatsoever, although by roasting they are cleaned and purified , thus yielding their Silver more easily. This is especial ly the case with mixed sulphide s and native Silver. The other kinds of black silver ores, as has been said, are best smelted , on account of their nature. If not smelted, then it is best to roast them until they change colour and lose their lustre, treating them at once by cooking. N everthel ess, they can be treated raw, tho!lgh at the expense of much more time than with other ores. To treat by cooking, however , it is necessar y to add Copper Sulphat e, Alum, Salt, or somethi ng containi ng Salt, like urine, or strong brines, which have the effect of roasting , in that they remove the brillianc e and glassiness that prevent amalgam ation of the ores. Nevertheless, these reagents act more quickly, and eat the Copper of the cauldron s, unless they are held back, as explaine d further on. The holding- back of the reagents also has its inconveniences. He who would treat the raw black silver ores, after grinding should incorpo rate an abundan ce of reagents , as well as much salt and sufficient water. The charge should be thoroug hly worked up until it is seen that it changes colour, as will happen when helped by time, heat and the mixing. This effect will be attained more quickly 158

FUNDACIĂ“N JUANELO TURRIANO

BOOK III

159

and with less risk from excessive working over, if the ground ore and reagents are thrown into a tub and beaten strongly with the stirrer until it is seen that the colour has changed. The Copperas and Salt will then be removed in the manner already explained, and the charge can then be safely treated by cooking.

FUXDACIĂ“N JCANELO TURRIANO

CHAPTER SIX HOW TO ERECT THE CAULDRONS IN WHICH ORE IS TO BE TREATED

In whatsoever way Fire is applied to the cauldrons so that the contained water will boĂl, there will be attained the desired Effect, which is to remove the Silver quickly from the ores without undue loss of Quicksilver. However, to obviate a part of the cost, and prevent difficulties which might arise, it is best to erect the cauldrons in the following manner: Make a furnace in the shape of a Box, using Adobes of strong mud, kneaded with clay, sand, dung and salt water. The width of the top opening will be such as is necessary for the cauldrons, and the length to correspond to the number of cauldrons. Let there be one flue for each pair. Four cauldrons will be sufficient; thus the furnace will be four and a half times greater in length than in width. In the middle of this space erect two small walls, distant the one from the other by half a Vara. Place grate bars of Iron, Adobes or Bricks, such as are used in reverberatory furnaces. This is like a floor on which to light the fire and sustain the wood and coals in such a way that the ashes separate and fall into the ash-pit. On each side of the firebox leave an opening to communicate with the chambers under the cauldrons; the floors of these chambers must be one palm higher than the grate bars. This floor under the cauldrons is built on arches which correspond in size and number to the cauldrons to be used, so that one arch corresponds to each cauldron. In the upper arch or roof of the furnace leave sufficient space for the entrance of the cauldrons. At the ends of the furnaces leave two openings or 160

FUNDACIĂ“N .rt:ANELO TURRIANO

BOOK III

161

chimneys for the escape of smoke and to provide draft. The part of the floor immed iately under each cauldro n will be made somew hat concave; in the lowest point of each concav ity, leave an opening three or four finger-thicknesses in diamet er, commu nicatin g with the bottom floor, also made bowl-shaped in its entirety . With the furnaces built in this way, the cost of wood fuel

for cook~ng 1s reduced by one-half. Also, much of the fuel necessary in roastin g can be saved by charging pieces of ore in the available space under the cauldrons, through two opposite doors; these can be closed by Adobes when convenient . If by chance, when a charge is being boiled in an old cauldro n, the bottom should be rupture d, the Quicksilver, most exposed to risk on account of the fire, would escape through the hole in the upper floor to the lower floor FUNDACIĂ“ N JUANELO TURRIANO

lยก! :i '1

162

ARTE DE LOS METALES

r i 11

ยก,

where it would not be exposed to heat, and a considerable part would be recovered with little or no loss. A-Arches on which is built the floor of the furnace. B-Fire-door. C-Ash-door. D-Grate-bars. E-The two walls and openings through which the fire is led to the two groups of cauldrons [Fire-bridges.-Translators]. F-Floor of furnace. G-Concaves beneath each cauldron, with an opening in the centre, through which, if a cauldron is ruptured, the Quicksilver will escape to the lower floor. H-Openings for charging ore to be roasted . 1-Cauldrons. K-Chimneys. L-Another door at the front of the furnace, also for charging ore to be roasted.

FUNDAC Iร N JCANELO TURRIANO

CHAPTER SEVEN INSTRUCfiON S FOR TREATING ORES BY COOKING

Grind and screen them to the greatest Fineness possible. If, when the ground ore is taken bet:ween the fingers, there can be felt the sharpness of coarse Sand, throw it into tubs, or Bateas, with sufficient water, stir very well, and, after a brief rest the fine will separate from the poorly ground, which will settle to the bottom. Charge the slime and water into the pots or big cauldrons, beneath which, a short time previously, fire has been kindled. Add one or two Botijas (Rawhide buckets, averaging to-day in Bolivia, say, seven gallons - Tr.anslators) of clear water, according to the capacity of the cauldrons together with the necessary Quicksilver, according to the Richness of the ore. This, however, should never be less than enough to cover the bottom of the cauldron, so that in whatsoever part ore may settle, it will be in contact with Quicksilver. Continue stirring slowly, although, in boiling, the water will cause a certain amount of movement in the ground ore, if the Sand is not very coarse. Through this stirring with the Quicksilver, the Silver will unite with and become incorporated therein, and in a short time the values will be recovered. Keep the water boiling, so as not to interrupt or prolong the work. To make up for the loss in boiling, add an equal amount of hot water, or, by a Launder of easy slope, continuously run in water in such proportion that it will not stop boiling, but yet will equal the consumption; this can be controlled easily by watching the rise and fall of the pulp line in the cauldrons. Judge the quantity of ground ore to be treated at one charge, according to the size of the cauldron. If there is 163

FUNDACIĂ“N JCANELO TURRIANO

164

ARTE DE LOS METALES

too little ore and too much water the work will be multiplied.

If there is too much ore the charge will be too thick, making difficult the agitation caused by boiling. Using a ladle from time to time, take a Sample from the bottom to determine the progress of treatment anci whether Quicksilver should be added, or, if desired, a part of the amalgam already formed may be removed. The slime or fine sand taken out in the sample should be returned to the cauldron until the charge is finished, and the ore has given up all its Silver. This state will be recognized through applying the Instructions given further on.

FUNDACIĂ“N JCANELO TURRIANOj

CHAPT ER EIGHT WHICH SHOWS THAT THIS IS THE TRUE WAY TO RECOVER VALUES FROM ORES BY AMALGAMATION, WITH NEITHE R LOSS NOR CONSUMPTION OF QUICKSILVER, AND IN THE SHORTEST TIME

The natural affinity and liking of Quicksilver for· the Metals is sufficiently proven, when other Argume nts might lack, by the way it unites with, penetrat es and drinks them, converti ng them into what we call amalgam. There is no other thing in the World that has this quality; it stands apart from all the other Metals in the World. Neither is there an Equality in the friendship it manifests towards the metals. There are degrees, according to their perfection, and it is thus that it unites most speedily with Gold; next Silver; after these, other metals; and lastly with Iron. This seems to confirm what has been said about the Genesis of Iron. On this property of Quicksilver is founded the present- day treatme nt of the ores of Gold and Silver by amalgam ation, an Art not practise d in ancient times. Not even Georg Agricola, in his copious work on the treatme nt of ores, makes mention of it, although this work was written only eighty-seven years ago. He does touch lightly upon the assaying of Gold, and on how to recover that which is finely divided. Quicksilver in its ·natural state is always disposed to seize upon and unite with Silver; but the ores of silver are rebellious to Quicksilver on account of the veil or film with which N ature provides them. It is shown by Experience that the grinding and heat of the operatio n, together with the mixture of reagents which clean, consume and wear off this film, bring the ore, little by little, to such a condition that immedia tely the Quick165

Fill<DACIÓN JUANELO TURRIANO

166

ARTE DE LOS METALES

silver and Ore unite. Even the inexperienc ed must admit that in the treatment of ores by cooking, all these factors concur with great improveme nts. The more the charge is worked over, the better, and it is thus that fifteen minutes' boiling gives the same results as are attained after Days and even Months in ordinary work. The virtue which Copper imparts to the water cooked in it attracts and conditions the Silver better than a multiplicat ion of reagents; but heat is, without comparison , the greater factor, penetrating and taking effect on all part of the charge. Thus, by this method, no more Hours are occupied in recovering the value of the ore, than Days by the ordinary process. The Quicksilver cannot escape, nor is there risk of loss, by this process. T o claim that it might be expelled by the considerabl e Heat would show more than Ignorance, because it is protected by the covering water. Even children know how to boil Oil in a paper, without burning the paper itself, and how to place in lighted coals an Egg, around which has been tied a Thread, without burning the Thread. Even when water has been boiled strongly in a cauldron, the bottom will not impart a heat unbearable to the hand that touches it. In great vessels of pure lead, salt water is cooked in Germany (and may so be done wherever desired) until the Salt crystallizes ; yet the violence of the fire does not alter this soft and easily-melt ed metal. The troubles called consumptio n and loss of Quicksilver , as has been shown, are due to the excessive subdivision caused by grinding, whereupon it escapes with the Water and Slimes. This inconvenie nce does not exist when ores are amalgamat ed by the cooking process, because all the Quicksilver is in the bottom of the cauldron in one body. Without an excessive movement, if the treatment is carried on as it should be, floured Quicksilver will never be seen. These clear Assertions always conform with actual Experience .

Fill\DACIĂ“N JUANELO TURRIANO

CHAPTER NINE HOW TO RECOGNIZE WHEN THE ORE HAS GIVEN UP ITS VALUE; AND HOW THE CHARGE SHOULD BE CLEANED UP

The determinat ion to a certainty, by fire assay, of the Silver contained in the ores to be treated by amalgamat ion, is a necessary preliminary , whatsoever the method used. The determinat ion of whether the ores have yielded their values in the cooking is even more easy, because he who may so desire can remove nearly all the amalgam which the charge should render, befare starting the clean-up. The upper part of the Quicksilver is that which is continually taking up Silver, because it is immediatel y in touch with the ore containing it. The heat communica ted through the bottom of the cauldron maintains the amalgam in suspense, and does not allow it to unite equally with the whole body of the Quicksilver. And it is thus that nearly the whole of the amalgam is above, as a cream of two, three or four fingers' thickness, according to the richness of the ore, and the time given for the amalgamat ion. It is easily removed with spoons. The slimes may be washed off in clear water as the amalgam is ladled out; it will remain white and pure without necessity of other treatment. If the ore is very rich this skimming is important, and additional Quicksilver should be charged, so that the treatment is shortened, the balance of the Silver is quickly recovered, and the charge is finished. Also, without removing the amalgam, in the manner aforesaid one may determine, by studying the purity and colour of the amalgam in a ladle sample, whether the ore has yielded up its value. This is the practice in ordinary amalgamation, though not always the best, for the Reason 167

FUNDACIĂ“N JUANELO TURRIANO

168

ARTE DE LOS METALES

explained further on. The most suitable and appropnate Rule in amalgamation by cooking is to stir up a small amount of the fine charge two or three times in the horn spoon, with a little Quicksilver. If it becomes bespangled, through picking up sorne Silver, the values in the charge are not yet all recovered. If it picks up nothing, the charge has nothing more to yield. The reason for this is that the ore is so well conditioned that, without any loss of time whatsoever, any Silver that has remained in the charge has become linked to the clean Quicksilver. When it has been proven by the rules given that the charge has yielded up its value, cease firing. Remove the bridge and take out the Stirrer. When the charge ceases to boil, bail out the slime water in Bateas, or drain through spigots placed in the cauldrons just above the setting. It may then be run off in ditches where it will cause no disturbance, and with the assurance that it will carry no Quicksilver nor Silver. Remove the sand which may have settled on the amalgam. If the transmitted heat should continue persistently to impede, correct with cold water thrown into the cauldrons. F or the rest, proceed as when using the ordinary clean-up tubs. And, for greater satisfaction, do not throw away the tailings until they have been assayed by fire. If there is necessity they should be reground.

Fill-!DACIĂ“N JCANELO TURRIANO

CHA PTER TEN PRIMARILY THE DISADVANTAGES OF THIS PROCESS, AND S THE DANGER OF RUPT URIN G THE CAULDRON

on That which at first sight and in the common Opini impormake s this Meth od of treatm ent seem to be of little al gener the to tance or advan tage is the ease (according botUnde rstan ding) , with which Quicksilver penet rates the r in toms. Ther e is the mani fest risk of losing all the Silve withnot is tion the ore, as well as other thing s. The objec years out found ation ; because such a thing happe ned sorne in ago in the Provi nce of Los Chichas, I being at the time man in certa A . the neigh bouri ng Provi nce of Los Lipes arly who owned a Mill at that place, knowing that I was regul ut any recovering amalg am by this Meth od, tried, witho ing work a on od Meth furth er Knowledge, to carry out the are they if scale. The cauld rons will last a long time in the const ructe d rightl y and in the mann er described ienced exper an as , where Four th Chap ter of this Treat ise, for me d serve opera tor, I testif y that a very thin Copp er jar five years conti nuou sly in this work , witho ut breaking. a The aforesaid mill-owner was, at the same time, and ds, Moul in F ound er of Bells; he cast the cauld rons errors. with the custo mary Alloy of Tin, both very gross amalHe had only a hears ay knowledge of this Meth od of the se becau e, failur gama tion,. and could only follow it up to m botto Wate r and Quicksilver could not prote ct the thick again st the violence of the Fire. That part There fore it had, of Nece ssity, to melt. rated , penet touch ed by the Quicksilver also was easily because of the alloy. The slight resist an ce of sorne cauld rons or j ars to Quick s sheet er Copp silver is due to soldered Joint s or to the 169

FUNDAC IĂ“N JUANEL O TURRIA NO

170

ARTE DE LOS METALES

being beaten out from spongy ingots, causing flaky sheets, easily penetrated. The greatest damage received by the cauldrons is in the circumference at the junction of the Quicksilver and Pulp, due to the continuous pounding of the boilings. It is remedied by a band of Copper of the thickness of a Real de ĂĄ ocho (Spanish coin of the epoch, about one-eighth inch thick-Translators ), or a little more, and three or four finger-thicknesses in height, which is adjusted above the bottom to the inside wall of the cauldron. This ring receives the shock of the boiling, and, when in time it is worn out, it is replaced at little cost. All the Copper which may have been consumed will be replaced by Silver. One may also apply a Paste to that part of the bottom covered by the Quicksilver, thus totally obviating amalgamation or penetration. Make the Past~ from lime slaked in wine, slag of iron, and water-worn pebbles, finely ground, and incorporated with the well-beaten whites of eggs, or with oil. Firstly, clean the Copper well; then rub with oil, and apply the paste or varnish at once. If all the cauldrons are repaired with this paste they will last a very long time. However, the paste detracts from the Virtue which the Copper communicates to the water and ore with which it is in contact; therefore this remedy should only be used in that part of the cauldron to be occupied by Quicksilver. It would not be difficult to experiment with other means of protection, such as enamels, glazes, sulphur, smoke, eggs burnt in the bottom of the cauldrons, and other things which blacken the copper and serve as a film to resist the attack of Quicksilver. And if finally, through age (which consumes all things), a cauldron is ruptured, through the Neglect of him who should have detected and prevented the damage, this accident will not be serious, on account of the construction of the Furnace, as described in the Fifth Chapter. [That is, the holes in the upper floor of the furnace will allow the quicksilver to pass through and collect on the bottom of the furnace.-Translat ors.] FUNDACIĂ“N JCANELO TURRIANO

CHA PTER ELEV EN ESAID WHICH DISCUSSES WHET HER OR NOT THE AFOR WORK METHOD IS SUITABLE FOR LARGE SCALE

One of the most common Errors I have seen, even amon g Perso ns who presum e to know much of the subjec t, is their self-persuasion that exper iment al results canno t be duplicated on a worki ng scale. When Persons are not able to duplic ate the small-scale test, it is a sure sign that they proceed by Chanc e and witho ut Reason in what they are doing. Havin g a certai n Knowledge of what they did, they would know how to maint ain the neces sary Propo rtion and proceed on a large scale in accordance with the experi ss Proce ence gained in small-scale work. A handi cap to this is the belief of sorne that it is not possible to duplic ate exper iment al results. This is a manif est Decep tion, and opposed to the very N ature of Thing s, althou gh in sorne Parts and on sorne occasions, such duplic ation may not be practi cable. The mater ial from which the cauldrons are mad~, which is Copp er, is by no means lacking in these Kingd oms; rathe r is there an Abun dance of its ores. The fabric ation s of the cauldr ons is easy, as only the botto m (which carrie large. the Quicksilver) has to be of one piece, and that not The rest ·i!' added as sheets, until the size desired is attain ed, witho ut any difficulty whats oever . It is then surrou nded A and fortified with lime and brick, for greate r firmness. vessel of this sort, as ordina rily used in the heatin g and boiling of Soap or Sugar , will hold from fifty to one hundr ed gallons of water . The boiling with Quicksilver must necessarily be aided by stirrin g the considerable quant ity of ore al in the cauld ron, with the Stirrer. Thus, throu gh the natur 171

Ftr.\DAC IÓN JL:ANELO TURRIAN O

172

ARTE DE LOS METALES

Virtue of the Copper (which accomplishes the conditioning of the ore), and the aid of Heat, the Quicksilver escapes flouring, and of necessity it quickly picks up the Silver without Loss or Consumption (as these Occurrences are called). Only he who judges it impossible to boillarge quantities of water in adequate vessels, either fashioned of Copper or lined therewith, has grounds for denying that this Process can be used on a large scale; and one can well see on what a false principie this belief would be founded. Even if, by Imagination, one could conceive of a District ·which had Copper but had none to elaborate it, and which had neither wood nor other material sufficient to sustain fire, this would only be the result of Chance, and would not remove the certainty nor the possibility of the Art, which, like others, cannot be practised without fire.

FlmDACIÓN JCANELO TURRIANO

CHAP TER TWEL VE THE CONSUMPTION OF FIRE-WOOD

The inexcu sable consum ption of Fire-wood is the thing which, with more appare nt Reason , might cause sorne Discre dit to this metho d of treatm ent. N ecessarily there must be a great store of fire-wood, upon which are spent many Ducat s. N everth eless, the distrus t caused when only the consum ption of Fuel is considered is modified when one compa res the Expen ses and Saving s of this and other metho ds. Moreo ver, I know, by experience in the many mining Distric ts in which I have been, that the Provin ces of Chicha s, Lipes, Charc as Paria, Carang as, Pacaje s and Omasu yo aboun d in Fire-w ood; and, in the most barren and almost uninha bited Highla nds, N ature has provid ed in great abund ance what we call Yareta, more suitab le for burnin g than ordina ry Fire-wood becaus e it is so greasy , and full of resin. In order that this matter may be more clearly unders tood, I will calcul ate the cost to-day in this Imper ial Village of Potosí for the treatm ent of one Cajon (s6oo pound s) by the ordina ry metho d, as agains t what the treatm ent by cooking would be. I choose Potosí becaus e it is the mining Distri ct where wood is known to be the scarce st and deares t in this Kingd om. There is spent in grindi ng the charge (thoug h the figure is not exact, becaus e sorne charge s take more Time than others ) approx imatel y ten Pesos in twenty days; two Pesos in reagen ts (two Pesos' worth more of salt than in the cooking treatm ent, which needs very little); and three Pesos in the washin g (clean- up); and if ore yields around fifty pound s of amalg am, or one hundre d and sixty ounces of Silver, there will be added ten pound s of Quicks ilver for 173

FWDACIÓ N JCANELO TURRIAN O

174

l 11

1ยก ยก 1

l! li 1ยก

ARTE DE LOS METALES

what is called Consumption and another three pounds for Loss. This Quicksilver, at one Peso per pound, makes thirteen Pesos, and with the seventeen Pesos of other expenses amounts to thirty. In a furnace such as is used to-day for roasting ores, there is consumed each Shift (as the time between daylight and darkness is called) two Quintales anda half (250 pounds) of Y areta, and the same in the night, sustaining a continuous fire. This, at six Reales (seventy-five Centavos) the Quintal (and at times it is worth less), amounts to three Pesos, six Reales for the five Quintales. Divide the Cajon (56oo pounds) among eight cauldrons of moderate size; fire through the two furnace doors, arranged in the furnace as described in Chapter Five. At the rate used to-day, ten Quintales of Yareta will suffice to fire these cauldrons for twenty-five hours. And although so much time is not necessary for the ore to yield up its value, to better prove the case, allow double the consumption of Yareta or twenty Quintales. This will amount to fifteen Pesos and, with eight Pesos for Indian Labour, a total of twenty-three. By this calculation a saving of seven P esos is attained. One recovers the Silver which would be carried off (in the ordinary method) in the thirteen pounds of Quicksilver, and this is equal to another twenty-four ounces, worth nineteen Pesos, or a saving on each Cajon of more than twenty-five Pesos. There is also a gain in Time, as the treatment of one month is reduced to one day. The ores yield a sixth more of their content, and nothing is left in the coarse sand, because one can and should treat Slimes only by this method. And if, with ores yielding around fifty pounds of amalgam to the Cajon, there can be saved more than twenty-five Pesos, through treating them by cooking, who cannot see the great sum to which this would amount in treating ores of a higher grade, which would necessarily consume more Quicksilver in the ordinary process? In each four retorts of three hundred and twenty ounces of amalgam there will be a saving of two hundred and thirty-six P esos, which is FUNDACIร N JCANELO TURRIANO

BOOK III

175

enough of a Gain and Saving to help cover the cost of the cauldrons. Moreover, that part of the · cauldron which gradually becomes amalgamated and scraped off will in time have yielded more than the price of the cauldron itsel[ The amount of Copper in the amalgam is too little to deteét by assay. This intercharge of Copper and Silver not only compensates for the cost of the cauldrons, but is a source of no little gain as well. When the ores of a mine may seem to be of too low a grade to treat by this method (and there is no mine but has sorne low-grade ore) let the high-grade be sorted out and amalgamated by cooking. This can be profitably done, and it will be of great advantage to the Miners to be able to get to-day the Silver in the ores they mined yesterday.

FlmDACIÓN !CANELO TURRIANO

CHAPTER THIRTEEN THE DRAWBACKS TO THIS METHOD AND THE REMEDIES

The speed and great violence with which the Quicksilver and Silver unite in this method of treatment is the reason why at times the amalgam is baser than that obtained in the ordinary method. This is most likely to happen in the treatment of ores containing much heavy Plomo, called Anca, which (as has been said before) is impure native Silver. The Quicksilver picks it up quicldy through the aid of the boiling, and no time is given for the elimination of the impunt1es. It might well happen that it would purify itself by continuing the boiling, but to avoid excessive Delay it is not always best to do this. Therefore, when it is proven that the ore has yielded its Silver, one may stop the treatment and take out the amalgam as though it were pure. Wash it with clean Quicksilver, without adding water; on stirring a few times with the hand, all the impurities will rise to the top. The scum which may be on the surface is to be removed as many times as necessary, until the Quicksilver and amalgam are clear as a mirror. The leaden scum taken off the top is put back in the next charge, if it belongs to the same Owner; or, it may again be washed with Quicksilver, as before, and thus reduced to but little volume; or, it may be worked over in a Batea with salt and ashes, or lime, being rubbed well with a piece of tile, as in the ordinary clean-up. Lastly, it may be retorted, melted and refined on a cupel bottom. When the ores treated abound in Sulphur, as do all kinds of black Silver ores, the Quicksilver will become very black during amalgamation and will not pick up the Silver. It will be a wise precaution to have the ores roasted to eliminate 176

[il

FUNDACIĂ“N JCANELO TURRIANO

BOOK III

177

the Sulphur, as has been said before. He who, through Curiosity , desires to treat the ores without roasting, may do so by adding, while cooking, Copper Sulphate, Alum or Salt, or substance s which contain Salt, such as brines or urine. With the change of colour in the ore, the Quicksilver will become clear and amalgam ate with the Silver. Much would be saved by treating the black Silver ores in this way, if the ensuing damage to the cauldrons was not so certain. Both the weakenin g of the cauldrons and the cost of reagents are to be considered, and therefore the black Silver ores should not ordinarily be treated by this method; nor can the ore be advantag eously prepared by cooking in sorne other kind of vessel with the reagents, but without Quicksilver. Vessels made from clay, even the most thickly glazed, will leak or filter, while those of iron will corrode and turn to copper. I cite these facts so that no one may suffer from such mistakes. Somethin g may be done by using cauldrons of copper or iron, entirely coated inside, as has been explained, or by many times working over the black Silver ores with the aforesaid reagents, according to _directions given. Neverthe less, it is easiest to roast the ores; only that the possibilit y of treating the ores raw may be seen, have I written the above.

FUNDACIĂ“N JCANELO TURRIANO

CHAPTER FOURTEEN HOW AMALGAM MAY BE OBTAINED FROM COPPER ORES BY COOKING

li 11

¡ 1

r: 11

l!l i !¡

Exceedingly rare are the ores of Copper which yield amalgam when ground or incorporated with Quicksilver. Among the many Copper ores which I have seen in all these Provinces, one only have I found which would do it. This I found on a Plain in the Province of Los Lipes, a little more than one league from Sabalcha, and on the road to Colcha. It is an ancient Indian working, and although the ores are rich in Copper, they carry no Silver whatsoever. The little care manifested in sorting the ores proves to a certainty that the Indians sought only the finest of the Green and Blue pieces, which they called Cibairo. Associated with this ore there is a mixture of sorne kind of impure native Copper which will unite with Quicksilver. It is the only Copper ore I have seen which will yield amalgam in the ordinary treatment of Silver. By cooking, however, all Silver-bearing Copper ores will yield their· value, if treated by the method and with the precautions which follow: The cauldrons in which the Copper ore is to be treated must be of Iron and of no other material, if the desired results are to be attained. All kinds of Copper ores, except the Sl}lphides, we call Pacos (Oxides). They may be green, light, dark, or of sorne other colour. There is needed no preparation, except fine grinding and the cooking as with the ores of Silver. The sulphides of Copper, whether they are steely or brilliant, or whatsoever colour they may be, one must roast until they have lost their lustre. And because in the roasting there is produced much Copperas (Sulphate) the charge 178

[il -

FUNDACIÓN JCANELO TURRIANO

1 •

BOOK III

179

must be washe d as described before, until it is all removed. Boil the charge at once, and all the Silver which the Coppe r ore may contai n will be reduced to amalg am. lf the roaste d ore is charge d into the iron cauldr on (witho ut removing the Coppe ras), it will wear it out, andin a short time conve rt it to fine Coppe r. In additio n to the aforesaid, the cauldr ons of Iron possess the inhere nt and particu lar virtue of livening and reviving the Quick silver when almost destro yed and conver ted into anothe r substa nce. This is but anothe r ofNat ure's marvels, to be studie d and admire d. Quicksilver is the same, in this respect, as Solimán (Corrosive Sublim ate) althou gh the latter is very different in that it is soluble in water like common salt. Boil this ground sublim ate with water in an iron vessel, afid it will be reduced at once to its original form of common and lively Quicksilver. The effects of this occult proper ty of lron have been demon strated since the custom of using it (finely divided) in the charges was introd uced, thus stoppi ng to a great extent the loss of Silver. In the cooking of a charge, this Virtue is quickl y and easily made available throug h the greate r heat impar ted. He who would care to fully enligh ten himself may cook ground Sublim ate in a vessel of other materi al, as long as he likes; but, boíl the water as much as he will, no Quicksilver will be seen. Let him throw a piece of Iron into the vessel, and within a short time he will find the sublim ate reduced to liquid Quicksilver. It is better, though , if the vessel be entirel y of lron, as has been said.

FUNDACIÓN JuANELO TURRIAN O

CHAP TER FIFTE EN HOW TO MAKE A BOILING AMALGAMATION CLEAN-UP ON CHARGES WHICH HAVE BEEN COLD AMALGAMATED

li 1

Althou gh the Reader has been warned of the causes of the loss and consum ption of Quicksilver in ordinar y amalga tion, and partial Remedies have been pointed out in the treatise given on this subject , it would be most difficult (even by obeyin g all Instruc tions) to obviate entirely these disturb ing evils. It may happen that a charge will get into such conditi on that the Quicksilver becomes soluble, as has been said concerning Sublim ate. In this case none of the previous Warnin gs is of avail, and it is not only advisable but necessary to clean up the said charge by cooking in large iron cauldrons, arrange d in the way explained for the Copper cauldrons. Thus, with a few boilings, aided by the movem ent of the stirrer, the floured Quicksilver will amalga mate with the Silver, and that Quicksilver which may have become soluble will be restore d to its original form. That this transm utation of the Quicksilver in the charges is not impossible, seems befare now to have been proven by the experience of the many amalga mators who have recovered neither Silver nor Quicksilver, when both were abunda nt in the charge. There is not sufficient ground for attribu ting this total loss to the floured Quicksilver. In additio n, there are often present , in the charges, substan ces which combine with the Quicksilver and conver t it to Sublim ate, but in the absence of the somew hat dry and intense Heat which is necessary to the action of these Substan ces, the change cannot be attribu ted to them. Also, Nitric Acid will dissolve the Quicksilver, and frequently the ore will be accompanied by substan ces very 180

FUNDACIĂ“ N JUANELO TURRIANO

BOOK III

181

simila r to those from which it is· distilled. In such cases, the vapou rs and moisture will reduce the Quicksilver to a liquid. Althou gh these vapours are not so strong as the distilled acid, it is within reason to attribu te these effects to them, even though the changes do not occur with the quickness and violence attend ing the use of common Nitric Acid. Suppose, then, that the Quicksilver becomes soluble; it is clear that it will be lost, whatso ever care is used, when the charge is washe d; and all will be lost withou t remedy, if the charge is not cleaned up by boiling, aided by Iron. And althou gh it might savour of an arroga nt T emerit y to den y that N ature provides sorne other thing to give this same effect, to this day at least it is not known if there be such. The truth of this will be recognized by those who are well versed in the Philos ophy of the Transm utatio n of Metal s; those who are not so learned will have to believe it. If cauldrons of Iron are lacking, Copper, well arranged in the usual manne r, may be used to wash the ordina ry amalgamat ion charges. Cook and stir until a test of the surface slimes gives no sign of fl.oured Quicksilver. Thus will be recovered almost all the Quicksilver which, as loss and consumpt ion, would otherwise have been short, and the ore will better yield the value it has contained. There may also be placed in the cauldrons, while the charge is being boiled, sorne bars or pieces of iron, as before mentio ned; these will aid in the reduct ion of the Quicksilver that may have become fl.oured, or dissolved.

FUNDACIÓN JCANELO TURRIANO

CHAP TER SIXTE EN THE AMALGAMATION OF RICH ORES OF GOLD AND SILVER 1

;

'11

!i¡

The ore in which pure Gold or Silver is visible, mixed with rock, is called M achacado. [This word is still general ly úsed in Southe rn Peru, Bolivia, and Chile, to designa te ores carryin g visible gold, silver, or coppe r.- Translators.] E ven though it may not be so rich as the sight judges, there is need of guidan ce as to the method of treatin g it. If it has to be amalga mated, it can neither be ground well, nor will the Quicksilver seize such coarse Gold and Silver. If treated by smeltin g the dry rock, withou t flux to accomp any, it is a very great disturb er for the furnace, whatev er the method , and the metal and rock cannot be separat ed withou t risk or much loss. This was the experience of those who discovered the beautif ul and rich M achacado ore of Turco, in .the Provine e of Carang as. There was a heavy loss until a friend of mine (a miner then, but now a monk of the Francis can order) taught them the method of treatm ent called Tintin (morta r and pestle). In a hard Rock make a round concav ity of one-qu arter rara or more in diamet er at the top, the same or more in depth, like unto a Mortar , with the circumference diminishing, as that of a pyrami d, until it termin ates below in a space of no more than four finger-thicknesses. Charge into this space sufE.cient Quicksilver and the M achacado ore broken to pieces. Crush with a heavy iron bar, rounde d at one end, as is the Pestle of a Mortar . Throug h the strong agitatio n the Quicksilver will amalga mate with the Gold and Silver. The fine slime goes off in the water, which continu ously enters the hole on one side throug h a narrow Launde r and flows out on the other. 182

FUNDAC IÓN JUANELO TURR IANO

BOOK III

183

Collect these slimes in a pit and treat them later with Quicksilver, as before mentioned, when they will yield considerable profit. This is very necessary, because the Ruby Silver and Black Silver ores or any other kinds of ores, even if they are very rich (and these at times accompany the Machacado ore), so long as they are stone-like, and so are ground and converted into Powder, will escape from the Tintin without yielding up their silver. The quantity of ore which can commodiously be treated by this method will be small. T o use this method on a larger scale it is necessary to use the apparatus described farther on. It should be noted first, though, that not only the free-milling ores created by N ature in the mines should be thus treated, but also the products containing free Gold and Silver, obtained by roasting lump Sulphide ores. This is especially true in those ores which contain tarnished Silver. The roasting, carried out according to the Richness of the ore, results in much saving and profit. In the mining Districts of these Provinces, where, on account of the lack either of Water or of Money, it is impossible to construct wet-crushing plants, two other methods of fine-grinding, using Stones, are well known and used. One is called the Trapiche (Chilean mill) and the other the Maray (Rocking stone). [Now usually known in Bolivia as Quimbalete.-Translators.] Both use two large and hard pieces of stone, the lower one, called Solera (Sole-piece) being imbedded on a level with the ground. The upper (crushing) stone of the horse-driven Trapiche, is in the shape of a Wheel, or whole Cheese, like unto the Atahonas, or olive mills. The upper stone of the Maray is like unto a Half-moon or Crescent. To the upper parta pole is tightly lashed, so that two Workmen, grasping the extremities, can rock the stone without much fatigue. Through the weight and the force of the rocking blow, the ore is easily broken clown. The construction of both of these devices is simple and familiar, and therefore I do not stop to describe them. I would only say here that in grinding free-milling ores t he FUNDACIĂ“N JCANELO TURRIANO

184

ARTE DE LOS METALES

Sole-pieces should not be level, but with a concave path sufficiently large to allow the runner to move freely. Water enters at the highest point of the Sole-piece, through a narrow Launder. At the bottom of the concavity is the necessary Quicksilver. Throw in the ore to be ground, and when it is fine enough the free Gold and Silver will be taken up by the Quicksilver; the balance, converted to a fine slime, will flow off in the water through another Launder; it will then be recovered and treated as previously described.

A-Tintin (Mortar). B-Barreta (Pestle). C-Entering water. D-Slimy water. E-Gocha or pit for saving slime. F-Square sole-piece of Trapiche (Chilean mill) or Maray (Rocking-stone). G-Round sole-piece. H-Runner of the Trapiche. I-Maray (Rocker). K-Long pole to rock the Maray.

FUNDACIĂ“N JUANELO TURRIANO