Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr
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Mining labor costs from $2.25 to $3 a day. The lode or deposit worked is from 15 to 70 feet or more in thickness. The ore is hoisted to the surface by steam-power. The deepest shaft has a depth of about 500 feet. Steam is used for power by the several mills. There are two mills attached to the Homestake mine—one of 80 and the other of 120 stamps. These 200 stamps have been in continuous operation for about six years. From 1882 to 1885, production has increased from 179,000 to more than 213,000 tons worked at a yield of about $6.00 per ton. The Father de Smet mine has 100 stamps crushing a little more than 100,000 tons with a yield of $3.40 per ton. A Visit to Leadville An E&MJ; correspondent detailed his trip to Leadville, Colorado, in the July 21, 1883, edition . To the lover of grand and majestic scenery, a journey from Denver to Leadville, via the Denver & Rio Grande Railroad, is a treat not soon to be forgotten. Nothing could be grander than the Grand Canon of the Arkansas, and no visitor from the East should miss seeing it. Arriving at Leadville, all was hurry and bustle, and trade was very brisk, as the mines were all making their monthly pay- ment of wages. Harrison avenue is filled every day with busy people, hurrying to and fro; while in the evening, the foot-walks are almost impassable from the crowd of toil- ers, whose day's work is over and who are out seeking amusement and social inter- course with friends. Leadville and its surroundings have been so often described that it must be pretty well known now; nevertheless, for the sake of those who may not know, or who may have forgotten, I may say that it lies on a gently sloping plateau, between two gulches. at the foot of the mountains bounding the eastern side of the Arkansas Valley, and about five hundred feet above the river-bed. Around it, to the north, east and south, and within a radius of about five miles, lie the mines which are the chief source of its wealth. To the north- east, about one mile away, is Fryer Hill, containing the celebrated Robert E. Lee mine, the Matchless, Chrysolite, Little Pittsburg, Amie, Little Chief, and several others. Eastward, on the suburbs of the city, is Carbonate Hill, with the Morning and Evening Star mines, the Catalpa, Henriett, Agassiz lease, Gonabrod, Leadville Consolidated, and others upon it. Behind it lies the most celebrated part of the camp at present, namely and leas- es, Iron Mountain, possessing in its depths the Silver Cord…. The largest producing single mine is the Silver Cord, where I was most courteously received by T.S. Wood, who at once pro- posed that I should go down the mine and see for myself. So having donned some mining toggery, I descended, and, in charge of the foreman, was shown a part of the mine where they were the busiest. No. 3 station contains one of the most magnif- icent breasts of solid hard carbonate I ever saw. At present, it stands 25 feet by 20 feet of solid ore. In places it has reached a depth of 60 feet. Here and there, the sparkle of large lumps of galena could be seen. Altogether, it was a splendid site, even for one who was not a shareholder. It was impossible, in the time of my dispos- al, to visit the other parts of the mine, which runs on an incline 800 feet deep into the hill. I was told that they had struck it quite as rich in other parts. The output runs between 3500 and 400 tons per month and the ore contains gold as well as silver, and a considerable quantity of lead. The Diamond Mines of South Africa A story written by Gardner F. Williams (November 13, 1886) puts a burgeoning diamond discovery into perspective . These mines are situated in Griqualand West, which is now a part of the Cape Colony. The town of Kimberley is in latitude 28° 40' south, longitude 25° 10' east, about 640 miles northeast of Cape Town, and 450 miles from Port Elizabeth on the east coast. It is connected with these towns by a railroad that has been completed dur- ing the present year. The mines are located in a desert country, resembling the desert portion of Arizona. The elevation above sea- level is about 4000 feet. The climate is exceedingly hot during the summer months. Diamond Deposits—There are four large diamond-bearing deposits at Kimberley, all lying within a radius of one and a half miles, having the De Beers mine as the center. These are named the Kimberley, De Beers, Du Toit's Pan, and Bultfontein mines. The first diamond is said to have been found in 1867 by some Dutch children on a farm near Hope Town, about 90 miles south of Kimberley. In 1869, natives dis- covered the Star of Africa, which weighed 83 carats. The discovery of these dia- monds lead to a rush described by the writer: The year 1870 saw the banks of the Vaal River suddenly, as by magic, densely populated with tents of huts of every size and shape. The river diggings were the pre- cursors of the great mines . In July, 1871, the famous Kimberley mine was discovered. This is by far the richest of all the mines. The farm, on which are situated the De Beers, Kimberley, and St. Augustine mines, was purchased by the government of the Cape Colony for £100,000. The De Beers and Kimberley mines are held and worked under the old system of paying to the gov- ernment a monthly license fee of ten schillings for each claim…. In 1873, Kimberley had grown to be a town, with a population of from 20,000 to 25,000, while neighboring towns and camps were nearly deserted. In 1876, the method of washing the diamond bearing ground superseded the old method of dry sorting; and the percentage of diamonds saved was largely increased, thus proving that a large percentage of diamonds had been thrown away while the old dry sorting was in vogue. The debris from the Kimberley mine was sought after and washed, in preference to mining virgin ground in other mines…. The surface [of the Kimberley mine] was originally blocked off into claims of 31 feet square, and, within a week from discovery of the first diamond, about 1500 licenses to work claims had been granted…. The original system of mining the Kimberley ground, namely, by open quarry, was without a doubt the best for a depth of 200 ft, because the mine could have been worked in no other way while the claims were operated by individual owners…. In whatever manner the diamonds may have been formed, they must have crystal- lized before they were deposited in the mass in which they now occur. No dia- monds have been found either in the shale or in the hard rock surrounding the "blue," as might be expected if the diamonds had crystallized where they are found…. The miners would soon choose another method for working the mine, by sinking shafts into the solid ground outside the mine, and drifting to the "blue" ground, and then the deposit was mined by drifting and stoping. The miners found the blue ground to be richer in diamonds the deep- er they mined. However, the amount of water they hoisted amounted to 13 million gallons per year at a cost of 6 pence per load of 100 gallons . 66 E&MJ; • MARCH 2016 www.e-mj.com E & M J 1 5 0 Y E A R S