For several reasons the Roberts-Victor mine is one of the most important of the new mines of South Africa. Its initial capital is £160,000, divided in one pound shares. With one exception, the diamonds from this mine have brought the highest price per carat of any. In 1906 the average price 0f the Dutoitspan diamonds was 80s. II.52d., whereas the Roberts-Victor brought only 75S., but in the value 0f the yield per load it far exceeded any other. One hundred loads of Roberts-Victor brought over £260, whereas with a higher price per carat, the yield of the Dutoitspan was so much smaller that one hundred loads brought but a little over £100.
The mine is in the Orange River Colony near Boshof, about forty miles from the Kimberley mines. It was acquired by the present company from the original owners in 1906. At that time there were about ninety claims. The company now owns 500 acres.
Work in the mine began in May, 1906. The percentage of carats per load for the first month was .91, but it fell so that the average for the first year was .698. To the end of December the yield was 20,406 carats, which left a profit after deducting the expenses of prospecting, developing, mining operations and registration, of £39,045. Out of this, however, the Orange River Colony is entitled to a share, the maximum being forty per cent. of the profits.
The output for 1907 was 132,809 carats, but the percentage of diamonds per load was still less, being given as .536. It is considered one of the most promising of all the South African mines, as it combines fine quality with abundance. The diamonds are of very good color and many of the crystals are very perfect and beautiful.
The Voorspoed is an Orange River Colony mine capitalized at £400,000 in £1 shares. Work commenced in 1907, and the first six months yielded 46,340 carats at an average of .21 of a carat per load. They realized an average of thirty shillings per carat. Only one mine yields less in money value per load, the Lace. Nevertheless it is confidently expected that it will be a factor in the diamond market, as it will probably produce three to four hundred thousand carats per annum. The crystals are usually small and of mediocre quality. The average yield including 1909 has been a little over .19 carats per load. The year 1909 yielded a total profit of £53,870.
The Koffyfontein continues to turn out in the neighborhood of ten thousand carats monthly. The output for March, 1910, was 9,803 carats, which were sold at an estimated profit of £7,500. At that time there were over one million loads of blue ground on the floors.
The ” Frank Smith,” and ” Otto’s Kopje ” diamond mines, are situated in Griqualand West, between the Vaal and Hart rivers about forty miles from Kimberley. The former produced about 23,000 carats in 1904 and 1905 but did not pay and has been closed down. The latter from August, 1900, to July, 1902, produced diamonds which realized £21,425 exclusive of one of 336% carats. It did not pay and was closed at that time and a proposition made to reorganize the company.
In 1909 in German South West Africa, 14 producers won 560,977 carats worth £836,000. Eighty-five per cent. was sufficiently good to cut. The average size of the stones was one-fifth of a carat. About eighty per cent. of the output was sold in Antwerp and Brussels, the balance being distributed in Amsterdam, Germany, London, New York and Paris. The net profits after paying expenses and government charges amounted to £34,500.
Several large diamonds have been found in the Barkly district during the winter of 190910: a fine blue-white stone of 90 carats and a very good one of 653% carats at Baboon Island, and one of 35 carats on the Barkly West Commonage.
The diamond chimneys are usually somewhat funnel-shaped at the surface, so that many of the surface locations on the edge of them ran out with depth.