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Diamond Mines - The Dutoitspan

( Originally Published 1911 )



DIAMONDS had been found in the dry bed of a stream on the Jagersfontein in August, but the first opening on a diainondiferous volcanic pipe in Africa was made in 1870, when prospectors discovered diamonds on the Du Toit's Pan, owned by a Boer farmer named Van Wyk. After trying in vain to regulate the diggers and collect license fees, he sold his farm for 2,600. The farm lay about twenty-four miles south and a little east of Pniel on the Vaal, where the diggers first made their headquarters. All the so-called mines worked prior to this discovery were merely diggings in alluvial deposits, as this also was supposed to be at that time. Many diggers were attracted to it in the beginning, but the discoveries of the Bultfontein, De Beers, and Kimberley, following in rapid succession, drew many away, especially when it was learned that the two last were much richer in diamonds. So small was the yield near the surface that little persistent work was done on this field until 1880. As the diggers neared a depth of 200 feet, the yield improved so greatly, and the diamonds were distributed so evenly through the rock, that the work was prosecuted with more vigor, and the mine's output was brought up to a considerable amount.

The average yield at that time was, it is claimed, about three-quarters of a carat to the load.

Not only was the Dutoitspan the first of the Kimberley mines discovered, but it is also much the largest. The original locations numbered 1,441 claims, equal to about 23% acres; nearly four times as many as on the Kimberley pipe, but none of the Kimberley pipes are as large as the first locations indicated, because some were outside the diamond-bearing area. Like the others, it began with individual diggers, then the grouping of claims in the hands of small owners and speculators who floated them into stock companies, and in turn consolidated, until at the time of the De Beers Consolidation in 1889, " The Griqualand West Mining Company " owned about half the pipe. Cecil Rhodes said of the mine, " It is too poor to work, and too rich to allow others to acquire it," and for that reason it was forced into the Consolidation. Those who opposed the amalgamation, claimed that the De Beers people wanted it in order to close the mine. Barnato, on behalf of the De Beers, denied any such intention, saying that the government would not permit it and also that the licenses due the London and South African Exploration Company amounted to such a large sum that it would not pay to do so. The mine was practically closed at that time as far as open working was concerned. Heavy falls of reef had materially damaged it. What diamonds were being taken out cost about the same as they brought, viz.: 6s. to 7S. per load. The De Beers argued that if the various owners could not make it pay with open working they certainly could not with the more expensive underground system. A majority of the owners agreed; the terms offered by the De Beers were accepted, and the Dutoitspan became a part of the Consolidation. The De Beers management, nevertheless, having gained control of the mine, did close it down and kept it idle until they succeeded in buying up all the outstanding shares. Then they made preparations to work it.

When the De Beers began to work the mine, there was about a hundred feet of water in it. Pumps were installed and about 296,000,000 gallons removed. On August 13, 1901, a shaft in the reef was begun and sunk to 775 feet. It went through:

Ft.

Debris 19
Basalt 106
Shale 239
Conglomerate 6
Quartzite 82
Diorite 63
Melaphyr 269

This arrangement of the strata differs from those surrounding the other mines of this group, as the company had never met with diorite before, nor had they ever encountered quartzite above the melaphyr. It is sup-posed to be a displacement by the intrusion of the diorite.

From the main cross cut, drives were run to a distance of 500 feet, and it was estimated that the mine contained in sight above the 750 foot level, 24,380,000 loads. The equipment of this mine has been exceptionally good. With the experience of years to draw upon, the best has been furnished. The equipment is electrical, Underground locomotives for haulage, hoists, and pumps are run by electricity. The washing plant is situated on the floors about a mile from the mine, and has a capacity of about six thousand loads per day. In 1905 the shaft was carried down to 814 feet.

The company did not meet with much encourage-ment at first, for their outlay. In 1904 only 3,032 carats were won at an average of .12 of a carat to the load, valued at 42s. 3d. per carat; 1905 made a much better showing, with 24,902 carats which brought 69s. 11d. per carat and a yield of .26 of a carat to the load; 1906 gave .25 of a carat which realized 80s. 11.52d per carat; 1907 at an average of .24 of a carat to the load, yielded 365,821% carats; 1908 showed an-other slight loss of average yield, it being .23, but the output brought 74S. 5.07d. per carat. The cost of producing in 1905 was very high, amounting to 47S. 3.3d. per carat, but was reduced nearly half in 1906 to 29s. 2d. per carat, and in 1907 to 27s. per carat. Unfortunately, just as the mine was becoming important as a producer, and profitable on account of the good prices the product commanded, the sudden falling off in the demand for diamonds, decided the management to close it on April 24, 1908, until business showed some improvement.

The quality of the diamonds in this mine has improved very materially with depth. Most of them show color but many are fancy. In the lower workings also there is an almost entire absence of fragments and broken crystals. In the eighties, Dutoitspan diamonds brought on an average about 23S. to 28s. per carat, or twenty-five per cent. more than the average of the three other Kimberley mines. The output at that time ranged from 500,000 to 700,000 carats per annum, about the same as that of the De Beers and of the Bultfontein, and two-thirds that of the Kimberley, the value being greater than either. Until the limit of open-working was reached, it was a great producer of valuable material, nevertheless Barnato at the first meeting of the De Beers Consolidated, stated that hardly one company had paid a dividend in the seventeen years they had been working it. That two companies on the mine, the Griqualand West, and the Anglo-African Company, had paid very small dividends, he attributed to the extraordinary financial ability of their respective managers.



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