Note note 8, p. 279 — BOOK VIII.

[Pg 279][8] Historical Note on Crushing and Concentration of Ores. There can be no question that the first step in the metallurgy of ores was direct smelting, and that this antedates human records. The obvious advantages of reducing the bulk of the material to be smelted by the elimination of barren portions of the ore, must have appealed to metallurgists at a very early date. Logically, therefore, we should find the second step in metallurgy to be concentration in some form. The question of crushing is so much involved with concentration that we have not endeavoured to keep them separate. The earliest indication of these processes appears to be certain inscriptions on monuments of the IV Dynasty (4,000 B.C.?) depicting gold washing (Wilkinson, The Ancient Egyptians, London, 1874, II, p. 137). Certain stelae of the XII Dynasty (2,400 B.C.) in the British Museum (144 Bay 1 and 145 Bay 6) refer to gold washing in the Sudan, and one of them appears to indicate the working of gold ore as distinguished from alluvial. The first written description of the Egyptian methods—and probably that reflecting the most ancient technology of crushing and concentration—is that of Agatharchides, a Greek geographer of the second Century B.C. This work is lost, but the passage in question is quoted by Diodorus Siculus (1st Century B.C.) and by Photius (died 891 A.D.). We give Booth's translation of Diodorus (London, 1700, p. 89), slightly amended: "In the confines of Egypt and the neighbouring countries of Arabia and Ethiopia there is a place full of rich gold mines, out of which with much cost and pains of many labourers gold is dug. The soil here is naturally black, but in the body of the earth run many white veins, shining like white marble, surpassing in lustre all other bright things. Out of these laborious mines, those appointed overseers cause the gold to be dug up by the labour of a vast multitude of people. For the Kings of Egypt condemn to these mines notorious criminals, captives taken in war, persons sometimes falsely accused, or against whom the King is incens'd; and not only they themselves, but sometimes all their [Pg 280]kindred and relations together with them, are sent to work here, both to punish them, and by their labour to advance the profit and gain of the Kings. There are infinite numbers upon these accounts thrust down into these mines, all bound in fetters, where they work continually, without being admitted any rest night or day, and so strictly guarded that there is no possibility or way left to make an escape. For they set over them barbarians, soldiers of various and strange languages, so that it is not possible to corrupt any of the guard by discoursing one with another, or by the gaining insinuations of familiar converse. The earth which is hardest and full of gold they soften by putting fire under it, and then work it out with their hands. The rocks thus soften'd and made more pliant and yielding, several thousands of profligate wretches break in pieces with hammers and pickaxes. There is one artist that is the overseer of the whole work, who marks out the stone, and shows the labourers the way and manner how he would have it done. Those that are the strongest amongst them that are appointed to this slavery, provided with sharp iron pickaxes, cleave the marble-shining rock by mere force and strength, and not by arts or sleight-of-hand. They undermine not the rock in a direct line, but follow the bright shining vein of the mine. They carry lamps fastened to their foreheads to give them light, being otherwise in perfect darkness in the various windings and turnings wrought in the mine; and having their bodies appearing sometimes of one colour and sometimes of another (according to the nature of the mine where they work) they throw the lumps and pieces of the stone cut out of the rock upon the floor. And thus they are employed continually without intermission, at the very nod of the overseer, who lashes them severely besides. And there are little boys who penetrate through the galleries into the cavities and with great labour and toil gather up the lumps and pieces hewed out of the rock as they are cast upon the ground, and carry them forth and lay them upon the bank. Those that are over thirty years of age take a piece of the rock of such a certain quantity, and pound it in a stone mortar with iron pestles till it be as small as a vetch; then those little stones so pounded are taken from them by women and older men, who cast them into mills that stand together there near at hand in a long row, and two or three of them being employed at one mill they grind a certain measure given to them at a time, until it is as small as fine meal. No care at all is taken of the bodies of these poor creatures, so that they have not a rag so much as to cover their nakedness, and no man that sees them can choose but commiserate their sad and deplorable condition. For though they are sick, maimed, or lame, no rest nor intermission in the least is allowed them; neither the weakness of old age, nor women's infirmities are any plea to excuse them; but all are driven to their work with blows and cudgelling, till at length, overborne with the intolerable weight of their misery, they drop down dead in the midst of their insufferable labours; so that these miserable creatures always expect the future to be more terrible than even the present, and therefore long for death as far more desirable than life.

"At length the masters of the work take the stone thus ground to powder, and carry it away in order to perfect it. They spread the mineral so ground upon a broad board, somewhat sloping, and pouring water upon it, rub it and cleanse it; and so all the earthy and drossy part being separated from the rest by the water, it runs off the board, and the gold by reason of its weight remains behind. Then washing it several times again, they first rub it lightly with their hands; afterward they draw off any earthy and drossy matter with slender sponges gently applied to the powdered dust, till it be clean, pure gold. At last other workmen take it away by weight and measure, and these put it into earthen pots, and according to the quantity of the gold in every pot they mix with it some lead, grains of salt, a little tin and barley bran. Then, covering every pot close, and carefully daubing them over with clay, they put them in a furnace, where they abide five days and nights together; then after a convenient time that they have stood to cool, nothing of the other matter is to be found in the pots but only pure, refined gold, some little thing diminished in the weight. And thus gold is prepared in the borders of Egypt, and perfected and completed with so many and so great toils and vexations. And, therefore, I cannot but conclude that nature itself teaches us, that as gold is got with labour and toil, so it is kept with difficulty; it creates everywhere the greatest cares; and the use of it is mixed both with pleasure and sorrow."

The remains at Mt. Laurion show many of the ancient mills and concentration works of the Greeks, but we cannot be absolutely certain at what period in the history of these mines crushing and concentration were introduced. While the mines were worked with [Pg 281]great activity prior to 500 B.C. (see note 6, p. 27), it was quite feasible for the ancient miner to have smelted these argentiferous lead ores direct. However, at some period prior to the decadence of the mines in the 3rd Century B.C., there was in use an extensive system of milling and concentration. For the following details we are indebted mostly to Edouard Ardaillon (Les Mines Du Laurion dans l'Antiquité, Chap. IV.). The ore was first hand-picked (in 1869 one portion of these rejects was estimated at 7,000,000 tons) and afterward it was apparently crushed in stone mortars some 16 to 24 inches in diameter, and thence passed to the mills. These mills, which crushed dry, were of the upper and lower millstone order, like the old-fashioned flour mills, and were turned by hand. The stones were capable of adjustment in such a way as to yield different sizes. The sand was sifted and the oversize returned to the mills. From the mills it was taken to washing plants, which consisted essentially of an inclined area, below which a canal, sometimes with riffles, led through a series of basins, ultimately returning the water again to near the head of the area. These washing areas, constructed with great care, were made of stone cemented over smoothly, and were so efficiently done as to remain still intact. In washing, a workman brushed upward the pulp placed on the inclined upper portion of the area, thus concentrating there a considerable proportion of the galena; what escaped had an opportunity to settle in the sequence of basins, somewhat on the order of the buddle. A quotation by Strabo (III, 2, 10) from the lost work of Polybius (200-125 B.C.) also indicates concentration of lead-silver ores in Spain previous to the Christian era: "Polybius speaking of the silver mines of New Carthage, tells us that they are extremely large, distant from the city about 20 stadia, and occupy a circuit of 400 stadia, that there are 40,000 men regularly engaged in them, and that they yield daily to the Roman people (a revenue of) 25,000 drachmae. The rest of the process I pass over, as it is too long, but as for the silver ore collected, he tells us that it is broken up, and sifted through sieves over water; that what remains is to be again broken, and the water having been strained off, it is to be sifted and broken a third time. The dregs which remain after the fifth time are to be melted, and the lead being poured off, the silver is obtained pure. These silver mines still exist; however, they are no longer the property of the state, neither these nor those elsewhere, but are possessed by private individuals. The gold mines, on the contrary, nearly all belong to the state. Both at Castlon and other places there are singular lead mines worked. They contain a small proportion of silver, but not sufficient to pay for the expense of refining." (Hamilton's Translation, Vol. I., p. 222). While Pliny gives considerable information on vein mining and on alluvial washing, the following obscure passage (XXXIII, 21) appears to be the only reference to concentration of ores: "That which is dug out is crushed, washed, roasted, and ground to powder. This powder is called apitascudes, while the silver (lead?) which becomes disengaged in the furnace is called sudor (sweat). That which is ejected from the chimney is called scoria as with other metals. In the case of gold this scoria is crushed and melted again." It is evident enough from these quotations that the Ancients by "washing" and "sifting," grasped the practical effect of differences in specific gravity of the various components of an ore. Such processes are barely mentioned by other mediæval authors, such as Theophilus, Biringuccio, etc., and thus the account in this chapter is the first tangible technical description. Lead mining has been in active progress in Derbyshire since the 13th century, and concentration was done on an inclined board until the 16th century, when William Humphrey (see below) introduced the jigging sieve. Some further notes on this industry will be found in note 1, p. 77. However, the buddle and strake which appear at that time, are but modest improvements over the board described by Agatharchides in the quotation above.

The ancient crushing appliances, as indicated by the ancient authors and by the Greek and Roman remains scattered over Europe, were hand-mortars and mill-stones of the same order as those with which they ground flour. The stamp-mill, the next advance over grinding in mill-stones, seems to have been invented some time late in the 15th or early in the 16th centuries, but who invented it is unknown. Beckmann (Hist. of Inventions, II, p. 335) says: "In the year 1519 the process of sifting and wet-stamping was established at Joachimsthal by Paul Grommestetter, a native of Schwarz, named on that account the Schwarzer, whom Melzer praises as an ingenious and active washer; and we are told that he had before introduced the same improvements at Schneeberg. Soon after, that is in 1521, a large stamping-work was erected at Joachimsthal, and the process of washing was begun. A considerable saving was thus made, as a great many metallic particles were before left in the washed sand, which was either thrown away or used as mortar for building. In the year 1525, Hans Pörtner employed at Schlackenwalde the [Pg 282]wet method of stamping, whereas before that period the ore there was ground. In the Harz this invention was introduced at Wildenmann by Peter Philip, who was assay-master there soon after the works at the Upper Harz were resumed by Duke Henry the Younger, about the year 1524. This we learn from the papers of Herdan Hacke or Haecke, who was preacher at Wildenmann in 1572."

In view of the great amount of direct and indirect reference to tin mining in Cornwall, covering four centuries prior to Agricola, it would be natural to expect some statement bearing upon the treatment of ore. Curiously enough, while alluvial washing and smelting of the black-tin are often referred to, there is nothing that we have been able to find, prior to Richard Carew's "Survey of Cornwall" (London, 1602, p. 12) which gives any tangible evidence on the technical phases of ore-dressing. In any event, an inspection of charters, tax-rolls, Stannary Court proceedings, etc., prior to that date gives the impression that vein mining was a very minor portion of the source of production. Although Carew's work dates 45 years after Agricola, his description is of interest: "As much almost dooth it exceede credite, that the Tynne, for and in so small quantitie digged up with so great toyle, and passing afterwards thorow the managing of so many hands, ere it comes to sale, should be any way able to acquite the cost: for being once brought above ground in the stone, it is first broken in peeces with hammers; and then carryed, either in waynes, or on horses' backs, to a stamping mill, where three, and in some places sixe great logges of timber, bounde at the ends with yron, and lifted up and downe by a wheele, driven with the water, doe break it smaller. If the stones be over-moyst, they are dried by the fire in an yron cradle or grate. From the stamping mill, it passeth to the crazing mill, which betweene two grinding stones, turned also with a water-wheel, bruseth the same to a find sand; howbeit, of late times they mostly use wet stampers, and so have no need of the crazing mills for their best stuffe, but only for the crust of their tayles. The streame, after it hath forsaken the mill, is made to fall by certayne degrees, one somewhat distant from another; upon each of which, at every discent, lyeth a greene turfe, three or foure foote square, and one foote thick. On this the Tinner layeth a certayne portion of the sandie Tinne, and with his shovel softly tosseth the same to and fro, that, through this stirring, the water which runneth over it may wash away the light earth from the Tinne, which of a heavier substance lyeth fast on the turfe. Having so clensed one portion, he setteth the same aside, and beginneth with another, until his labour take end with his taske. The best of those turfes (for all sorts serve not) are fetched about two miles to the eastwards of S. Michael's Mount, where at low water they cast aside the sand, and dig them up; they are full of rootes of trees, and on some of them nuts have been found, which confirmeth my former assertion of the sea's intrusion. After it is thus washed, they put the remnant into a wooden dish, broad, flat, and round, being about two foote over, and having two handles fastened at the sides, by which they softly shogge the same to and fro in the water betweene their legges, as they sit over it, untill whatsoever of the earthie substance that was yet left be flitted away. Some of later time, with a sleighter invention, and lighter labour, doe cause certayne boyes to stir it up and down with their feete, which worketh the same effect; the residue, after this often clensing, they call Blacke Tynne."

It will be noticed that the "wet stampers" and the buddle—worked with "boyes feete"—are "innovations of late times." And the interesting question arises as to whether Cornwall did not derive the stamp-mill, buddle, and strake, from the Germans. The first adequate detailed description of Cornish appliances is that of Pryce (Mineralogia Cornubiensis, London, 1778) where the apparatus is identical with that described by Agricola 130 years before. The word "stamper" of Cornwall is of German origin, from stampfer, or, as it is often written in old German works, stamper. However, the pursuit of the subject through etymology ends here, for no derivatives in German can be found for buddle, tye, strake, or other collateral terms. The first tangible evidence of German influence is to be found in Carew who, continuing after the above quotation, states: "But sithence I gathered stickes to the building of this poore nest, Sir Francis Godolphin (whose kind helpe hath much advanced this my playing labour) entertained a Dutch Mynerall man, and taking light from his experience, but building thereon farre more profitable conclusions of his owne invention, hath practised a more saving way in these matters, and besides, made Tynne with good profit of that refuse which Tynners rejected as nothing worth." Beyond this quotation we can find no direct evidence of the influence of "Dutch Mynerall men" in Cornish tin mining at this time. There can be no doubt, however, that in copper mining in Cornwall and elsewhere in England, the "Dutch Mynerall men" did play a large part in the latter [Pg 283]part of the 16th Century. Pettus (Fodinæ Regales, London, 1670, p. 20) states that "about the third year of Queen Elizabeth (1561) she by the advice of her Council sent over for some Germans experienced in mines, and being supplied, she, on the tenth of October, in the sixth of her reign, granted the mines of eight counties ... to Houghsetter, a German whose name and family still continue in Cardiganshire." Elizabeth granted large mining rights to various Germans, and the opening paragraphs of two out of several Charters may be quoted in point. This grant is dated 1565, and in part reads: "Elizabeth, by the Grace of God, Queen of England, France, and Ireland, Defender of the Faith, &c. To all Men to whom these Letters Patents shall come, Greeting. Where heretofore we have granted Privileges to Cornelius de Voz, for the Mining and Digging in our Realm of England, for Allom and Copperas, and for divers Ewers of Metals that were to be found in digging for the said Allom and Copperas, incidently and consequently without fraud or guile, as by the same our Privilege may appear. And where we also moved, by credible Report to us made, of one Daniel Houghsetter, a German born, and of his Skill and Knowledge of and in all manner of Mines, of Metals and Minerals, have given and granted Privilege to Thomas Thurland, Clerk, one of our Chaplains, and Master of the Hospital of Savoy, and to the same Daniel, for digging and mining for all manner of Ewers of Gold, Silver, Copper, and Quicksilver, within our Counties of York, Lancaster, Cumberland, Westmorland, Cornwall, Devon, Gloucester, and Worcester, and within our Principality of Wales; and with the same further to deal, as by our said Privilege thereof granted and made to the said Thomas Thurland and Daniel Houghsetter may appear. And we now being minded that the said Commodities, and all other Treasures of the Earth, in all other Places of our Realm of England...." On the same date another grant reads: "Elizabeth, by the Grace of God, Queen of England, France, and Ireland, Defender of the Faith, &c. To all Men to whom these our Letters Patents shall come, Greeting. Where we have received credible Information that our faithful and well-beloved Subject William Humfrey, Saymaster of our Mint within our Tower of London, by his great Endeavour, Labour, and Charge, hath brought into this our Realm of England one Christopher Shutz, an Almain, born at St. Annen Berg, under the Obedience of the Electer of Saxony; a Workman as it is reported, of great Cunning, Knowledge, and Experience, as well in the finding of the Calamin Stone, call'd in Latin, lapis calaminaris, and in the right and proper use and commodity thereof, for the Composition of the mix'd Metal commonly call'd latten, etc." Col. Grant-Francis, in his most valuable collection (Smelting of Copper in the Swansea District, London, 1881) has published a collection of correspondence relating to early mining and smelting operations in Great Britain. And among them (p. 1., etc.) are letters in the years 1583-6 from William Carnsewe and others to Thomas Smyth, with regard to the first smelter erected at Neath, which was based upon copper mines in Cornwall. He mentions "Mr. Weston's (a partner) provydence in bringynge hys Dutch myners hether to aplye such businys in this countrye ys more to be commendyd than his ignorance of our countrymen's actyvytyes in suche matters." The principal "Dutche Mineral Master" referred to was one Ulrick Frosse, who had charge of the mine at Perin Sands in Cornwall, and subsequently of the smelter at Neath. Further on is given (p. 25) a Report by Jochim Gaunse upon the Smelting of copper ores at Keswick in Cumberland in 1581, referred to in note 2, p. 267. The Daniel Hochstetter mentioned in the Charter above, together with other German and English gentlemen, formed the "Company of Mines Royal" and among the properties worked were those with which Gaunse's report is concerned. There is in the Record Office, London (Exchequer K.R. Com. Derby 611. Eliz.) the record of an interesting inquisition into Derbyshire methods in which a then recent great improvement was the jigging sieve, the introduction of which was due to William Humphrey (mentioned above). It is possible that he learned of it from the German with whom he was associated. Much more evidence of the activity of the Germans in English mining at this period can be adduced.

On the other hand, Cornwall has laid claims to having taught the art of tin mining and metallurgy to the Germans. Matthew Paris, a Benedictine monk, by birth an Englishman, who died in 1259, relates (Historia Major Angliae, London, 1571) that a Cornishman who fled to Germany on account of a murder, first discovered tin there in 1241, and that in consequence the price of tin fell greatly. This statement is recalled with great persistence by many writers on Cornwall. (Camden, Britannia, London, 1586; Borlase, Natural History of Cornwall, Oxford, 1758; Pryce, Mineralogia Cornubiensis, London, 1778, p. 70, and others).