Part 84

FIG. 331.—_“Cradle” for Gold-washing._ ]

The methods of carrying on the gold-seeking operations vary according to the nature of the deposit which is worked and the resources of the miner. The simplest, which was that most practised in the early days of the gold-fields, consists in throwing into a tub several shovelsful of the surface soil, and in pouring in water while the contents of the tub are stirred about with a spade. The lighter matters are washed away, but the gold by its great specific gravity remains behind. An improvement in this, but still a very rude process, is practised by aid of the _cradle_, Fig. 331, which is merely the trunk of a tree, hollowed out, and provided with transverse partitions and ribs. The auriferous earth is thrown into the upper compartment, which is then filled with water. The cradle is rocked, so that the water may wash away all but the gold and the heavy stones. Any particles of the former which may be carried out of the head of the cradle will be stopped by the ribs which cross the lower part. Machines for puddling by horse-power are now in use, and other contrivances have superseded the tub and the cradle in _surface-washing_. The auriferous earth obtained by excavating the soil from pits is washed in a similar manner, as is also the material reached by penetrating the deeper tertiary deposits, and by driving adits or tunnels along the ancient river-beds beneath the layers of basalt.

A mode of washing accumulations of auriferous earths by streams of water is employed where circumstances are favourable. A long inclined channel is constructed, and lined with boards; or, when the natural inclination of the soil requires it, a long trough is constructed and supported on trestles. The trough is made of sawn boards, 1½ in. thick, in sections 12 ft. long, and it has a width of about 1 ft., the sides being from 8 in. to 2 ft. high. The inclination of the troughs is from 8 in. to 24 in. in 12 ft., and depends upon the abundance of the water: the more water, the steeper is the slope. The bottoms of the troughs are crossed by a number of transverse bars, which arrest the auriferous particles in their descent. The _sluice_, or series of troughs, may be from 50 ft. to several hundreds or even thousands of feet in length, and the cost from £100 to £8,000. The earth is thrown in at the upper part of the trough, and it is gradually washed down, the water being allowed to flow in some cases by night as well as by day, but commonly in the day-time only, as the troughs must be watched, to see that they do not become choked up, and the soil washed out by the overflowing water. The _run_ goes on for six or ten days, and then the current is stopped for a _cleaning-up_, which occupies from half a day to a day. For this operation the stream of water is stopped, and quicksilver is used to dissolve the grains of gold from the sand, &c., collected by the _riffle-bars_. The quicksilver is afterwards expelled from the amalgam by heat, and the gold remains as a porous mass.

Sometimes, instead of shovelling the earth into the troughs, it can be washed out of its position into suitable channels by means of a powerful jet of water. This mode of working, which is termed _hydraulic jet sluicing_, offers great advantages where the natural conditions admit of its adoption. In this plan, instead of bringing the auriferous earth to the water, the water is brought to the earth by a flexible pipe, like the hose of a fire-engine, from a reservoir about 200 ft. higher, and the stream is directed upon the material by a nozzle. This powerful jet of water is used to separate and carry away the earth to the head of a system of channels and troughs, like those already described. The hose has a diameter of 8 in., but the orifice of the nozzle from which the water issues is contracted, in order to increase the force of the jet. The hydraulic jet sluicing requires from three to six men to work it, and the material of a hill can be carried into the sluices in less time than a hundred persons could do it by spades. Immense quantities of earth are removed in this way, and fatal accidents are not infrequent from the falling masses burying the men who carry the pipe. The force of the jet of water itself is another source of danger, for broken limbs and even fatal injuries have often been caused by it. The number of accidental deaths occurring in hydraulic jet sluicing operations in the colony of Victoria is reported to average about 60 in a year. Material which has been worked before often yields a considerable amount of gold when the operations are repeated; and in localities favourable to the hydraulic jet system, the work can be carried on with little labour. In this way three men have been known to extract in one week from dirt washed for the third time, gold of the value of £330.

The gold which is embedded in quartz and other minerals, as shown in Fig. 330, is obtained by crushing the material in stamping machines, which are usually constructed with logs of wood shod with iron. In another form of crushing-mill two large cast-iron rollers are used instead of stampers. From the crushed material the particles of gold are extracted by amalgamation with mercury, which is afterwards removed by distillation.

The richness of the Victoria gold-fields may be inferred from the fact that, up to the year 1868, 36,835,692 oz. had been obtained, the value of which is no less than £147,342,767. The total value of the gold then annually obtained throughout the whole world is estimated at about 20 millions of pounds sterling. When gold was found so plentifully in California and Australia, it was supposed by some that its value as a monetary standard would be affected. This has not happened, although the prices obtained for the metal by its producers were considerably lower in the last decade of the century than about 1867. The total annual output of gold throughout the world is of course variable, and no doubt there are also variations in the demand; but, so far, the fluctuations have been relatively small, and there has been no such depreciation by excess of production as in the case of silver. Yet the increased production of gold after the discoveries made about the middle of the century was beyond precedent. It has been estimated that between 1850 and 1875 the total value amounted to £600,000,000, showing an annual average twelve times greater than that for the period between 1700 and 1850. Between 1875 and 1890 there was a falling off in the supply, the annual average becoming only £20,000,000 in value. But since the last-named date there has been a rise year by year, and at the close of the century the value of the gold produced throughout the world in one year may not be less than £40,000,000.

As already remarked, the distribution of gold is world-wide; and it has happened in recent times, that just as one source of supply has shown signs of failure, other fields have been discovered and have attracted thousands of eager seekers to new regions. So, when the Californian supply was falling off, there came the rush to Australia, where easily worked alluvial deposits or rich veins continued for years to reward the toil of the gold-finder, though in an ever-lessening degree, until in 1886 or 1887 the centre of attraction was shifted. But at a later period fresh discoveries in Australia again raised the productiveness of that quarter; and still more recently, the announcement of the existence of much auriferous deposit in the valley of the Yukon River (Klondyke), and in various localities of British Columbia, drew thousands to desolate and undeveloped districts, in spite of the extremities of hardship and destitution that might be endured.

The discovery of 1886 takes us to South Africa, a region with which also our next section is mainly concerned, and the scene of an activity unprecedented in the annals of gold-mining. From circumstances immediately connected with our present subject, the close of our century finds public attention intensely occupied with affairs at the austral extremity of the “dark continent.” The history of South Africa, from the time when, in 1486, the tempest-driven Portuguese mariner, Bartholomew Diaz, first struck its shores at the promontory he named the “Cape of Storms” (_Cabo Tormentoso_), and when, eleven years afterwards, the celebrated Vasco de Gama sailed round it on his memorable voyage to India, is one which, in many respects, presents features of peculiar interest. It is not our province to enter into details of these, but it may be stated that the “Cape of Good Hope”—the more auspicious designation which the King of Portugal substituted for that of Diaz—was, towards the end of the seventeenth century, colonized by Dutch and some French settlers, and afterwards Table Bay became a regular port of call for Dutch, English, and other ships trading to India. The Cape was taken possession of by the British in 1795, but restored to the Dutch in 1803, only to be three years after (1806) resumed by England, under whose rule “Cape Colony” has since remained. The abolition of slavery in all British dominions, enacted in 1833, was the occasion of great dissatisfaction to the descendants of the Dutch settlers, who inhabited isolated farmsteads, their possessions consisting chiefly of great herds of cattle, tended by slaves. These people, or at least the majority of them, resolved to quit the confines of British territory, and seek fresh fields and pastures new in unoccupied regions north of the Orange River, so that from 1835 to 1838 there was a continued “exodus of the emigrant farmers.” The story of the following years, with its exciting events and the vacillating policy of successive British Governments, must be perused elsewhere: suffice it to say here, that the settlements of the “emigrant farmers” had by 1854 established themselves into two separate States, nominally recognising Great Britain as the “paramount power,” but practically independent of it; for, at the last-named date, the autonomy of “The Orange River Free State” was acknowledged, and two years before that another section of the Boers, _i.e._ of the “emigrant farmers,” who had settled beyond the Vaal River, was absolved from British allegiance, and, restricted only by a claim of certain suzerain powers, was constituted into “The South African Republic,” of which the precise boundaries were at length determined by the “Convention of London” in 1884. This territory is usually called for shortness the _Transvaal_, and here in 1854 the existence of gold was first announced; but the Boer authorities at once prohibited further prospecting, fearing, and perhaps with reason, that the winning of the precious metal within their bounds might disturb their pastoral quietude. The Boer character has been the unique product of a race withdrawn for two centuries from contact with European and civilized culture, living in widely separated dwellings with scarcely other associations than cattle and enslaved blacks. The Boer is described as of a type which draws away from the enterprising man of modern times towards the primitive patriarch centred in his flocks and herds: he hates innovations, and greatly distrusts strangers; he would rather keep, in a box under his bed, any money he may possess than employ it, or his own energies, in developing the immense mineral resources of his territory, in which are included not only gold, but copper, silver, lead, iron, and abundance of coal.

After some years the prohibition against the exploitation of gold in the Transvaal was withdrawn, and several localities in the Republic subsequently became small capitals of gold-mining industry. The most notable were Leydenburg and Barberton, at which latter place as many as 10,000 gold-seekers were congregated when the discovery of 1886 drew most of them away. These communities were formed almost entirely by the influx of people from beyond the Boer boundaries, mainly, of course, English-speaking people from the Cape Colony, Australia, America, etc. Their operations were hampered by the Transvaal legislation, and impeded by the absence of adequate means of communication, which was a characteristic feature of the Boers’ unprogressiveness; nevertheless, gold-mining has been pursued in some of these localities ever since, though with varying fortune. What drew nearly all the gold-seekers of the Transvaal and of adjoining regions at once to the north side of the Vaal River was the discovery there of _real gold mines_. This was at a district within the Transvaal territory, named Witwatersrandt (= White-waters-ridge), the designation which has been reduced by abbreviation or affection to “The Randt”—or, _anglice_, the Rand.

It is singular that although the Randt district had been explored by expert prospectors between 1877 and 1891, the outcrops of the auriferous reefs entirely escaped their notice. But when the first hint of the existence of these deposits was bruited abroad, it was the Kimberley men who were foremost in surveying the spot. By the Kimberley men we mean those who so soon had by lucky chance lighted in 1870 upon the rich and apparently inexhaustible diamond mines, as related in our next section. By the time of the announcement of gold-finds on the north side of the Vaal River many of these men had become rich—very rich indeed. If they had been so disposed they might then have returned to their native countries with enviable fortunes, but it was just as the affairs of their diamond companies had been settled by consolidation on a satisfactory basis, and the spirit of discovery and adventure was still strong upon them, that they resolved personally to explore the new El Dorado. To a wild desolate region they proceeded, enduring there and on the track thither the like discomforts they had experienced in their earlier quest. But they took with them experts provided with all appliances for ascertaining the prospective value of the alleged discovery, and, when convinced of its reality, they purchased from the Boer possessors their land at the price demanded, and it was not long before they had chemists and engineers at work, having, at the cost of making their own roads, had brought to the spot the necessary machinery and appliances. The usual influx of workers, builders, speculators, etc., followed, and in a wonderfully short space of time a town sprang up where in 1886 there had been only a single poor farm. The town grew rapidly to the dimensions of a city inhabited by 150,000 people. Its name is Johannesburg.

In his book on South Africa, the late Lord Randolph Churchill, describing Johannesburg in 1891, says that it has much of the appearance of an English manufacturing town, but without noise, smoke, or dirt. “The streets are crowded with a busy, bustling, active, keen, intelligent-looking throng. There are gathered together human beings from every quarter of the globe, the English possessing an immense predominance. The buildings and general architecture of the town attain an excellent standard, style having been consulted and sought after, stone and bricks the materials, corrugated iron being confined to the roofs, solidity, permanence, and progress being the general characteristics.”

The Randt mines having drawn into the South African Republic great numbers of enterprising workers, who have acquired wealth and built cities, it would have been expected that they would have been permitted to acquire the ordinary rights of citizenship. The Boers’ character, however, has been manifested by their refusal of such rights, and by their exacting grievous imposts from these _Uitlanders_ (Out-landers, or strangers), who, being for the most part of English race, are finding the injustice too hard to be borne, and greatly strained relations between the Transvaal and Great Britain have again supervened. Indeed, the situation has become so serious that it is feared actual war may result, and that is why, in almost the last year of our century, people are looking anxiously at the position of affairs in South Africa.

The geological conditions of the Randt are these: the upper series of beds in the _Karoo formation_, which extends over the greater part of South Africa, consist of quartzose strata, and in the district in question these are much broken, faulted, and variously inclined. They are interstratified with beds of sandstone and with the layers of gold-bearing conglomerate, of which last there are several parallel to one another and not far separated, ranging in their several thicknesses from 6 inches to 6 feet, the thickest being known as the main reef. These reefs form an oval basin,—that is, they dip with varying angle towards a centre, and crop out at their up-turned edges. Johannesburg is situated nearly 6,000 feet above the sea-level, on an elevated ridge, along which for 30 miles east, and nearly the same westwards, the northern outcrop extends, curving towards the south, while the southern edge of the basin appears in the Orange Free State, where it has been traced for a distance of 130 miles. There a shaft, sunk to the great depth of 2,400 feet, found the main reef with undiminished richness. The outcrop of the reefs stretches east and west for 130 miles, and the distance between north and south is 30 miles. From such data it has been inferred that the reefs contain altogether not less than 450 million pounds worth of gold. The conglomerate of these reefs consists of rounded quartz pebbles (which contain no gold), and pieces of sandstone and of argillaceous material, the whole cemented together into a very hard mass by iron pyrites. This last is the matrix in which the gold exists, in the form, for the most part, of minute scarcely visible crystals. To a depth of from 50 to 150 feet, air and moisture have acted on the pyritic matter, and the material of the reef becoming in consequence easily disintegrated, has yielded by mere mechanical treatment most of its gold, whereas by the same operations on the underlying hard, tough conglomerate, only about half its gold could be obtained. Hence, after breaking up the ore, the pyritic matter is sorted out and transported to the stamp battery, reduced to powder, from which about five-eighths of the contained gold is removed by quicksilver. The residue is concentrated by washing in a special machine called the “Frue vanner,” and the _concentrates_, after roasting in order to oxidize base metals, are subjected to the action of chlorine gas, by which the gold is converted into a soluble chloride, from the solution of which it is precipitated by ferrous sulphate. The _tailings_, _slimes_, and other residues are further acted on by a solution of potassium cyanide, which dissolves the minute remaining particles of gold, and from the solution the metal is obtained by electrolysis. By these supplementary chemical processes the total of the gold recovered from the ore is raised to 90 per cent. or more of all that chemical analysis shows to exist.

When it is said that the reefs are arranged in a basin-like form, it must be understood that this applies to their general disposition, for the regularity of geometrical shape does not belong to geological basins. There are considerable variations in the inclinations of the reefs: at some places they are nearly vertical, but generally they dip towards the centre at various angles, a slope between 25° and 45° being quite usual; and the inclination becomes less and less the deeper they go, so that it is presumed that the beds are level towards the centre of the basin. In the Randt the vertical shaft is rather the exception, the entrance to the mine usually following the inclination of the reefs, and the trucks of ore are drawn up sloping rails. From the inclined adits horizontal galleries are excavated right and left at various depths by which the main reef is worked, and there are cross cuts by which the reefs to the north and south may be reached. The most active district of the Randt is that which extends eastward of Johannesburg, where a long succession of tall chimneys and winding headgears together with the other appurtenances are visible. But there is nothing of a picturesque character about a gold mine, more than is presented by the aspect of an ordinary colliery.

The importance of the Randt gold-fields does not consist in the actual richness of the crude material, which indeed in places here and there cannot be profitably worked,—in mining parlance, it is not “pay ore.” It is rather the great ascertained extent of these gold-bearing beds and the general persistence of their character throughout that give to the Randt its unique character amongst metalliferous workings. This contrasts with the comparative uncertainty attending the exploitation of auriferous quartz veins, which occur in detached unconnected patches, that often end suddenly where least expected. There are in the Randt nearly one hundred companies working mines, and of these there are many that pay very handsome dividends on their original capital. A few pay 100 per cent., while a considerable number distribute 25 per cent. and upwards; so that some of these Gold Companies are amongst the richest and most influential financial houses in the world. The Randt is second only to the United States in the quantity it adds annually to the world’s production.

_DIAMONDS._

In ancient times, and down to a comparatively late period, the only region from which were derived all the diamonds that found their way to Europe, was India, where Golconda was long celebrated for the productive mines in its neighbourhood, and for the high estimation in which fine specimens of their yield were held. In the seventeenth century these mines employed 60,000 persons, it is said; and in other districts of India diamond-seeking has also been carried on from time immemorial. A gradual decrease in the finds of Indian diamonds has long been observed, and the supremacy the East had so long enjoyed as the purveyor of gems was in the earlier part of the eighteenth century transferred to another hemisphere. In 1727 the diamond was first discovered in Brazil; or rather, we might say, was then first discerned there. For the gold-seekers in washing the sands of certain Brazilian rivers had found numberless specimens which they either threw aside as worthless, or, seeing them prettier pebbles than the rest, used them as counters in their card games; their true nature was not recognized, because the rough diamond has by no means the attractive appearance of the cut and polished brilliant flashing with refractive radiance. It must have been these last, and not diamonds in their natural state, that presented themselves to the imagination of the poet when he penned the line—

Or deep with diamonds in the _flaming_ mine.