Sixty miles of smokestacks—from Krugersdorp to Springs—will suggest at once the magnitude of the great Gold Reef. Dynamite is blasting the gold-bearing ore for that distance 24 hours a day; black smoke is rolling out of high smokestacks from strong fires, under boilers in which steam is generated to furnish power to hoist the ore from thousands of feet underground to the stamp mills at the top; great dirt heaps—cyanide banks, as they are termed—circle about and wall in thrifty mining towns, that are not seen until a train stops at a railway station; monster stamp mills, whose crushing machinery resembles the roar of a sea beating on a rocky shore, are grinding the quartz into powdered dust—for nearly thirty years the Reef has been exploited, and is still giving up its precious ore. Hundreds of thousands of people are engaged in this gold mining industry; the eyes of the money people of the world are constantly watching the gold yield of the Rand.
In 1884 the output of the Transvaal gold mines was $55,000, and, save for a few years, during which the Boer war was being fought, the output increased until it has reached the enormous sum of $150,000,000 a year. The monthly output is from $12,000,000 to $15,000,000.
Native Huts and Kafir Corn (top); African Transport (bottom).
South Africa.
The stamps that crush the ore into powdered dust weigh from 1,800 to 2,000 pounds. Under the stamps are zinc-lined inclining tables, 10 feet long and 4 feet wide, covered with quicksilver. Water washes the thin dust over the tables, when the gold adheres to the quicksilver. The dust from five stamps passes over one table. When about an eighth of an inch of gold sediment has accumulated, the stamps cease working, and the residue is scraped off the zinc. The scrapings look like thick black mud. The sediment then goes through a drying process. The dried chunks of gold "mud" are next put in a kettle, or retort, and melted. Borax is tossed into the hot metal, which separates impurities from the gold, the precious metal remaining at the bottom of the kettle, the dross keeping to the top. More gold "mud" is put in the kettle, until there is enough to make a brick, or ingot. The gold metal is poured into a mold. Cooling in a few minutes, the red hot brick is dumped on the floor. The shape of an ingot is similar to a sponge cake, narrower at the bottom than at the top. The weight of an ingot is 1,000 ounces, its value about $20,000.
In early years the dirt that passed over the quicksilver was considered of little value, and was washed away. The dirt is now treated by what is termed the cyanide process. Remaining in large cyanide tanks, any gold contained in the dirt is reduced to a liquid. The liquid next goes to the extracting room, where it passes through inclining tanks, 12 feet long by 6 feet wide, composed of five compartments. The floors of these tanks are covered with 8 inches of zinc shavings. The liquid slowly passes from one compartment to another. Any gold contained in the chemical solution adheres to the zinc shavings. The shavings are then taken from the tank and put in a retort. At the same time sulphuric acid is placed in the retort, which causes the zinc to dissolve. The sediment in this instance is also like black mud. This is next put through a drying process, put in another retort, when the gold can be seen, poured into a mold, and dumped on a floor in ingot form. Some of the mine owners are very obliging to visitors who wish to look about the works. The mines range in depth from 2,000 to 4,000 feet.
Twenty thousand Europeans and 200,000 natives are employed in the Rand mines. Paul Kruger, nearly 30 years ago, fixed the wages of the white miner at $5 a day. Contract miners, however, earn as much as from $200 to $300 a month; but the average wage of the Rand miner is $160 a month. The natives' wage runs from 50 cents to a dollar a day and board. The hours worked are eight, three shifts comprising a day's force.