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DIAMOND in SOUTH AFRICA

Dry Diggings (suite)

The immediate result of the formation of these companies was a large increase in the production of diamonds; thus while the total output of diamonds in 1879 was about two million carats, in 1880 and 1881 it suddenly rose to over three millions. This large increase was rightly ascribed to the advantages resulting from the partial amalgamation of claims which had taken place, and it was strongly urged that this policy should be pursued to its logical conclusion, and that the whole of each mine should he placed under one management and one system of working. This proposition met at first with great opposition, but was effected in 1887 by the managers of the De Beer's mine, a company which, formed in 1880, gradually acquired claim after claim, until in 1887, with a capital of £2,332,170 ($324,324,516), it came into possession of the whole of the De Beer's mine. The formation and development of this company, which since 1887 has been known as the "De Beers Consolidated Mines, Limited", had the effect of greatly reducing the working expenses of the enterprise, which from 1882 to 1887 had amounted to 40 per cent of the value of the output. In 1882 the production of the diamonds cost the company 16s. 6d. per carat, while in 1887 this amount had been reduced to 7s. 2d. ; at the same time the deposit had increased in richness as greater depths were reached, an increase in the production of about 40 per cent having taken place. This increase in the richness of the deposit, combined with a diminished cost of production, naturally affected the dividends of the company, which rose from 12 per cent. in 1886 to 16 per cent. in 1887 and 25 per cent. in 1888.

In spite of the success, which has attended this effort in the direction of amalgamation, the management of the other mines has not yet been altogether unified, though they are more or less under the control of the powerful and heavily capitalized De Beers Company. This company now has possession of the whole of the Kimberley mine, and the new Wesselton mine, as well as of parts of the Du Toit's Pan and Bultfontein mines. Neither of these two latter mines, however, is now worked, since the open workings have become covered by falls of reef and the underground workings are not yet organized. An idea of the importance and influence of the De Beers Company may be gained from an inspection of the returns dealing with the production of diamonds. Thus from April 1, 1890, to March 31, 1891, this company alone produced 2,195,112 carats of diamonds, valued at £3,287,728 ($457,209,721), this being more than 90 per cent of the total yield (2,415,655 carats) of the four mines at Kimberley, or indeed of the whole of South Africa. This result is of course due in some measure to the large amount of capital, £3,950,000, at the command of the company.

The inception of this company and its pursuit of a policy of buying up all available claims resulted in a considerable rise in the price of the latter, £10,000 or even £15,000 being asked for single claims, and proportionate prices for portions. The claims thus acquired a definite market value, which depended on the richness of the deposit at that particular place, usually known fairly accurately, and which of course varied at different times. Thus the claims in the Kimberley mine in 1875 were worth from £200 to £2500 each, in 1878 from £50 to £6,000, and in 1882 from £150 to £15,000; the value of the whole mine being in these years £525,000, £1,300,000 and £4,150,000 respectively. At one time the value of the shares in the Kimberley mine amounted to £8,000,000 ($1,112,500,000).

In the other mines the deposit was poorer and the price of claims correspondingly lower. In the year 1880 the values of the richest claims in the Kimberley. De Beer's, Du Toit's Pan, Bultfontein, Jagersfontein and Koffyfontein mines were in the proportion of 10:5:2:1:1/10:1/15. In other words, the richest claim in the Kimberley mine was 150 times more valuable than the richest claim in the Koffyfontein mine; for the former £15,000 would be demanded and paid, while the latter would cost at the highest from £30 to £100.

For a short time after the opening of the mines each owner of a claim worked alone on his own piece of ground. It was found, however, that comparatively cheap labour could be obtained by employing the native Kaffirs, and these were soon engaged in large numbers. It is stated that in the seventies 10,000 to 12,000 Kaffirs were employed in the Kimberley mine alone, and by some authorities this number is doubled. The diamantiferous rock was excavated by the help of pickaxes or blasted with gunpowder, the latter agent being replaced later on by dynamite. The excavated material was then either loaded into carts or simply carried away from the mine. The whole mine was thus honeycombed with square pits which varied in depth in different claims, thus which had been vigorously worked being very deep and enclosed by high vertical walls, and others having the appearance of rectangular columns, so high that they sometimes fell over and buried neighbouring claims with debris. The roadways, by which the claims in the Kimberley mule were separated, soon came to be mere walls, the surfaces of which rose high above the floors of surrounding claims and gave the whole mine a peculiarly striking appearance, as may be gathered from this ancient illustration.

Owing to the ease and rapidity with which the tuff composing these walls became weathered, they formed anything but stable boundaries, and as early as 1872 they had to be removed. After their removal, the mine had the appearance of one gigantic pit; the rock subsequently excavated could not then be removed in the same manner as before, and other means had to be devised. The mine was surrounded by high, wooden stagings provided with ropes and winding machinery, by the aid of which the diamond-bearing material was hauled up in sacks or buckets of hide. The owner of every claim, or part of a claim, had his own hauling rope, so that at this time, about 1874, the total number of these ropes was very large and gave the mine, which is pictured in this old picture, the appearance of a huge cobweb. The winding was first effected by hand windlasses, then by horse, and finally by steam power, the delay in the adoption of the latter being caused by the cost of importing machinery and coal. In spite of this difficulty, there were in 1880 no less than 150 steam engines employed at the Kimberley mines, and in 1882 this number had been increased to 386 with a total horse-power of 4,000, and this was further supplemented by the use of 1500 horses and mules.

The continual increase in depth of the claims was attended by increasing difficulty in excavating the tuff and by frequent accidents, due to falls of loosened material. These difficulties were still further complicated by the fact that falls of reef also began to take place. Often masses of rock would fall sufficient to bury, wholly or in part, many of the surrounding claims and in such claims no further excavation of "blue ground" was impossible until the overlying mass of reef had been removed. In September of 1882, in the Kimberley mine, there was a fall of reef, estimated at about 350,000 tons, which buried no less than 64 claims; in 1878 one-quarter of the total area of the mine was strewn with fragments of reef. In 1879 and 1880, £300,000 was expended in removing this fallen material, and in 1882, £500,000 more was spent for the same purpose, and even then this obstacle to progress was not entirely removed. From the Kimberley mine alone a total of about four million cubic yards of reef have been removed, at a cost of £2,000,000. To what an extent the difficulties occasioned by a fall of reef influence the production of stones can be seen from the fact that the yield of the Kimberley mine, during the 18 months, which preceded the catastrophe mentioned above, was 1,429,728 carats, but in the following 18 months only 850,396 carats. The frequent falls of masses of reef and the removal of other masses, which threatened to fall, resulted in a great increase in the surface area of the mine. Thus in the middle of the eighteen hundred eighties, the Kimberley mine, a representation of which is shown in another old picture, was a crater-like pit 385 yards long, 330 wide and 400 feet deep.

Diamond Geology [ 1  India  3  4  5  6  7  8  Brazil  10  11  12  13  14  15  16  17  18  19  20  Borneo  22   South Africa  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  Venezuela, Guyana  42  Australia  44  Argyle  Congo  46  47  48  49  50  51  52  53  54  55  Angola  57  58  59  Guinea  ]


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Rafal Swiecki, geological engineer email contact

This document is in the public domain.

March, 2011