Diamond mining

“ In the first days of diamond mining there was no idea that diamantiferous earth extended to any particular depth, and miners were allowed to dig holes at haphazard and prospect where they liked. When the Kimberley Mine was discovered a new arrangement was made, and in July, 1871, it was cut up into about 500 claims, each 31 feet square, with spaces reserved for about fifteen roadways across the mine. No person at first could hold more than two claims—a rule afterwards modified. ”

“ The soundness of the investment of money in our Diamond Mining scrip under the diminished cost of working, owing to the extension of the railway, the increased care taken in the searching department, and consequently increased yield of diamonds, has been lately much taken advantage of by European capitalists, and at the present time I have never, for years, known the Fields in a more prosperous condition. ”

“ The captain was an expert in this river life, the Indians were chopping wood and bringing in game and fish, the blacks were busy now getting the mine started and later in digging, so that we were a very busy and quite contented colony.
Diamond mining on the Mazaruni is not [Pg 130] unlike gold dust mining. The diamonds, like the gold, being the heaviest substance in the gravel, naturally settle down to the bottom when a sieve is twisted about so as to make the water move around and around. The centrifugal force sends the heavy material to the bottom. ”

“ A recent application of the diamond is for wire drawing; a hole tapering towards the centre is drilled through a diamond, and the metal is drawn through this. No other tool is so endurable, or gives such uniform thickness of wire.
Distribution and Mining.—The most important localities for diamonds have been: (1) India, where they were mined from the earliest times till the close of the 19th century; (2) South America, where they have been mined since the middle of the 18th century; and (3) South Africa, to which almost the whole of the diamond-mining industry has been transferred since 1870. ”

“ Its seaboard at Parahiba, and for hundreds of miles north and south of it, projects into the Atlantic a thousand miles to the east of the direct line between its northern and southern extremities. Besides her diamond and gold mines, she possesses what is much more desirable, namely, valuable deposits of iron, copper, silver, and other metals. We have before us statistics which give the result of diamond mining in Brazil from 1740 to 1823, when national independence was won, which show the aggregate for that entire period to have been less than ten million dollars in value ”

“ On the favorable outcome of the valuation and the engineer’s report concerning the diamond deposits, we agreed to take care of the financial end. Not connected with any agreement with Arnold or Slack, was a plan to facilitate the passage of a law whereby a great territory of mining land could be taken up so as to insure to ourselves the entire field, no matter what the extent. ”

“ First we were to send a large sample of the diamonds to Tiffany, of New York, then, as now, the greatest American authority on precious stones, and have them thoroughly examined and appraised. If their value were proved beyond peradventure, then Messrs. Ralston, Lent, Roberts, Dodge and myself were to choose a mining expert to whom Arnold and Slack agreed to exhibit the diamond fields and permit a full examination of the same.
Nothing could possibly be fairer to all, and Arnold and Slack easily consented to these conditions, without a moment’s hesitation. ”

“ It not being possible to point out where the ancient river beds lie, smothered as they are by hundreds of feet of overlying drift, lava, and other later deposits, the only feasible plan is a series of boring with the diamond drill.
When gold has been discovered the finder must act with the greatest prudence, for even gold may be bought too dear. The surest test is a mill run, that is passing 10 to 50 tons through all the operations of crushing, milling, roasting, amalgamating, etc., and so ascertaining what returns are likely to be obtainable when the deposit is worked on a commercial scale. ”

“ To meet and neutralize the influence of this condition of affairs, the South African diamond-mining companies have limited production, which for the time has advanced prices. But the tendency obviously is for diamonds to decline in value ”

“ This is not to say that the proprietors of roadside rock shops buy all of their stock from others. Rock shops are abundant in areas of the United States that are rich in gem materials, and the shops tend to specialize in the local gem commodities, most of which the proprietors gather.
Rather than doing the mining themselves, owners of land that has a deposit of gem-quality minerals sometimes charge hobbyists for the right to collect gemstones. For example, diamond in Arkansas, opal in Idaho, and agate in Oregon and Washington are mined by hobbyists under this “fee digging” arrangement. ”

“ Many gold mines have been abandoned as unprofitable that could have been mined at a profit had their owners been wealthy and enterprising enough to do a great deal of expensive prospecting by diamond drill, cross cuts, drifts and rises. In one instance that came to the writer's knowledge a clever mining engineer cleared nearly $200,000 profit by leasing for a term of years a gold mine that was supposed to be exhausted. A drill hole sunk less than 50 feet below the old workings revealed a pocket of ore in the vein, and paying quartz was found for many hundred feet below. ”

“ In our day the mines are worked upon scientific principles, under the guidance of the ablest mining-engineering talent procurable in America. There are elaborate works for reducing the blue rock and passing it through one process after another until every diamond it contains has been hunted down and secured. I watched the “concentrators” at work big tanks containing mud and water and invisible diamonds—and was told that each could stir and churn and properly treat 300 car-loads of mud per day 1,600 pounds to the car-load—and reduce it to 3 car-loads of slush. ”

“ By far the greater part of the successful mining is still done by antiquated methods which have the advantage that they require little capital for an outfit. A miner's tools consist of a short-handled hoe with which to stir up diamond-bearing gravel in a sluice; a crowbar to pry up stone to lay bare deeper layers or to break down banks of clay or gravel; an iron hook on a pole with which to take diamond bearing gravel from beneath large stones or from cracks otherwise inaccessible ”

“ Winter Causes Lull, But Cold Fails to Chill the Ardor of Men Counting on Millions in Spring.
On July 30, 1872, the articles of incorporation of the San Francisco and New York Mining and Commercial Company were formally filed and the report of Expert Janin was made public. As yet, however, the exact location of the diamond fields was undisclosed, because the company’s rights to the great territories claimed were not completed, although a recent act of Congress changing the mining laws gave ample opportunity. ”

“ Even the ignorant African natives of today cannot be trusted to wear clothing while working in the diamond mines. No, the cause of high grading is the innate greed of human beings and it has existed from prehistoric time and among all peoples.
In this discussion as to grades of ore, the question may arise as to what might be reasonably considered the most attractive kind of a mining proposition. This is too knotty a query to be answered in a few words. There are so many different phases that must be given due weight. Every mine is a problem in itself. ”

“ A complete outfit for boring with the diamond drill includes a steam engine and boiler, diamond crown, lining tubes, rods, and various minor accessories.
Hydraulic mining is the cheapest known method of recovering gold. In four years the North Bloomfield Mining Company of California worked 325,000,000 cubic yards, which yielded only 2.9 cents of gold per cubic yard, and realized some profit. Very poor gravel will pay when the conditions are good. ”

“ They pointed out several spots where they had previously dug and found the precious stones, already mined and delivered in San Francisco. We all went to work with our primitive mining implements—picks, shovels and pans. Everyone wanted to find the first diamond. After a few minutes Rubery gave a yell. He held up something glittering in his hand. It was a diamond, fast enough. Any fool could see that much. Then we began to have all kinds of luck. For more than an hour, diamonds were being found in profusion, together with occasional rubies, emeralds and sapphires. ”

“ We have seen a report written by Henry Janin, a mining engineer of an established reputation who had visited the mines, examined them and reported favorably on them. He has accepted the position of superintendent and has expressed the opinion that with twenty-five men he will take out gems worth at least $1,000,000 a month. In this paper he attached so much importance to the discovery that he discusses the question whether the price of rubies and diamonds is likely to depreciate in consequence of increased production and answers the question in the negative. ”

“ So plentiful is the supply, and so inexpensive, comparatively, is the cost of mining that other diamond-producing works have almost entirely withdrawn from the industry since the South African mines were opened. It has been estimated that ninety-eight per cent of the diamonds of commerce are now supplied by these mines.
The British protectorate of Bechuanaland, lying to the north of Cape Colony and Griqualand and to the west of the Transvaal, has an [279] area of about 213,000 square miles, with a population of 200,000—mostly natives. ”

“ About three years ago, they say, an Indian near the diamond deposits gave several diamonds and rubies to a white man who brought them to Messrs. Roberts and Harpending in San Francisco. These gentlemen satisfied themselves of the value of the gems and sent men to hunt for more. They met the Indian after a long search, he took them to the place and was subsequently drowned. We tell the story as it was told to us.
“Then Mr. Janin went to the spot, washed a ton and a half of gravel, took out 1000 diamonds, four pounds of rubies and a dozen sapphires, and selected the best ground for mining. ”

“ Nothing can illustrate this better than the supreme folly of planting diamonds, rubies, emeralds and sapphires in the same matrix. A capable rogue would have consulted the history of mining for precious stones and would have readily discovered that they are never found associated in the same formation. This would have enabled him to avoid a raw monstrosity that should have led to exposure at the very start. Much of the other work was raw, as, for instance, the diamond and ruby spangled ant-hills and the flat rock, whose fissures were studded with precious stones. ”

“ This vast space of territory has not been examined scientifically, and but little is known of its condition except that it is diamond yielding. Since their discovery the mines have been worked with more or less activity with slave labor under the direction of companies of large capital. Skilled labor with the modern appliances of science has not yet been employed [Pg 38] in these mining districts. And the condition of the country, its laws, and the controlling power of the diamond corporations, will render the application of scientific skill a difficult and hazardous task. ”

“ Financial experts were in accord that the price of the white metal could not possibly go lower, was much more likely to advance than to recede. Even with silver at 80 cents an ounce, the profits on my mining operations would be enormous. I figured to clear such profits that in a few years I would receive back my capital investment and own a property with an earning capacity of millions. ”

“ The description of the properties of diamond would not be complete without a reference to the other valuable, if utilitarian, purposes to which it is put. Without its aid much of modern engineering work and mining operations would be impossible except at the cost of almost prohibitive expenditure of time and money. ”

“ While we cannot yet use the force that builds large white diamonds we can use the diamonds themselves. Set a number of them around a section of an iron tube, place it against a rock, at the surface or deep down in a mine, cause it to revolve rapidly by machinery, and it will bore into the rock, leaving a core. Force in water, to remove the dust and chips, and the diamond teeth will eat their way hundreds of feet in any direction; and by examining the extracted core miners can tell what sort of ore there is hundreds of feet in advance. ”

“ From the dull earth comes the bright sparkle of the diamond. Early prospectors, as gold-hunters panned the streams, sifted the surface gravel. When likely spots were located, men and machines began to dig. At Kimberly, the mine shaft is more than 3500 feet deep. One diamond may be secured for each 21 million parts of ore; but gem diamonds in the larger sizes are so much more rare than industrials or gems in the smaller sizes that more than 250 tons must be mined to yield a stone that can be cut and polished into a one-carat gem. ”

“ Diamonds in Africa have aided commerce, increased exportation and importation, indirectly helping the people at large, but they have not competed with gold in the political potentialities. They are found, when their stories are written, to be rather romantic than historical. Their is a fascination in the relation of the finding of South African diamond mines equal to the charms of fiction. ”