Thursday, October 22, 2009
The Big Hole Chapter Five
DECEMBER 14, 1978
In Kimberley I visited a mine that was completely different from all the others that I had seen in Africa. Instead of an open pit, the mine was entirely below the surface. In the entire world, there were then only six such underground mines. All of them were in South Africa: five hemmed in the mining city of Kimberley, and the sixth located 400 miles northeast in the Transvaal. The Wesselton, located only about a mile from downtown Kimberley, was the deepest of these diamond mines. The mine shaft extended 3,300 feet below the surface, which is deep enough to accommodate both towers of the World Trade Center in New York, stacked one on top of the other.
Before I was allowed to descend into the Wesselton, I was taken to a spotlessly clean changing room and provided with the necessary mining gear. This included steel boots, a white jumpsuit, a steel helmet with a built-in lantern, and a portable battery, which I strapped around my waist. I then proceeded to the mine shaft where I was met by Edward Robinson, a soft-spoken South African, who had been born and raised in the mining area around Kimberley.
At the top of the mine shaft, we stepped into a steel cage, the size of a large freight elevator. The door clanged shut. Robinson pressed a button, and with a sudden jerk, we began hurtling down the mine shaft. We were falling at a rate of twenty feet per second, or twelve miles an hour. Even at that speed, it took slightly more than two minutes to reach the mining level, 2,500 feet below the surface.
From all the films I had seen about coal mining, I expected to step out into a dark tunnel where men were hacking away at the rock with picks and shovels. Instead, I found myself standing in an enormous well-lighted and air-conditioned chamber. The ceiling was at least fifteen feet high, and there was a road in it wide enough for a two-ton truck.
"We call this the block cavina method," Robinson said. "It works on the same principle as punching a hole in the bottom of a bottle to drain the liquid out." He explained that rather than scooping out the kimberlite ore from above, as is done in open-pit mining, a shaft is drilled in the bedrock that encases the volcanic pipe. Once underneath the main body of ore in the pipe, or "the bottom of the bottle," as Robinson put it, a series of tunnels that run parallel to the surface are dug under the pipe. This is the "mining level." The kimberlite above, loosened by dynamite, then simply pours into the tunnels.
Robinson's attention focused on something happening at the end of the tunnel we were entering. He held up his hand. Suddenly, everyone around us froze.
A voice counted in Afrikaner "... schwi ... di ... ein." Then there was a loud explosion, followed in rapid succession by four other blasts. I could feel the reverberations of the concussion and smell burnt sulphur in the air.
"They're dynamiting ahead," Robinson calmly said. The dynamite came, he explained, from De Beers' own explosive factory, which was the largest in Africa.
Robinson motioned to follow him into the tunnel. At one end, kimberlite ore was flooding in. A black worker operated a powerful winch. It manipulated a bulldozer blade about thirty yards away. The blade scraped kimberlite ore through a hole in the floor of the tunnel.
The ore poured into a train of hopper cars on the level below. It was fully automated. The train arrives under the opening just before the scraper forces the ore through it. When full, it then shuttles over to the mine shaft where it dumps its ore. A belt of continuous buckets then bring the ore to the surface and deposit it on the conveyor belt. In all, this highly mechanized form of mining required about 165 men, including supervisors, below ground. Most of the workers were black, and the supervisors were white.
Robinson said that it was the white labor unions that insisted that the whites be given supervisory positions, rather than the blacks. He explained that some 40 percent of the black workers were tribesmen from Lesotho on seasonal contracts (while in South Africa, they lived in De Beers-- owned dormitories, called "hostels," and received about $40 a week in salary).
Before Robinson became manager of the Wesselton mine he had worked at one of the Anglo-owned gold mines. The mining level there was more than one mile below the surface of the earth, and the temperature of the walls in the cramped tunnels reached 12o degrees Fahrenheit. Unlike kimberlite, which when loosened flows by gravity into the mining tunnels, gold ore must be chiseled out of bedrock with picks and drills. "The seam at times was no wider than a pencil line, and there were literally thousands of men chipping away at it," he said. "There are more workers in a single gold mine than in all the De Beers diamond mines in South Africa."
When we returned to the surface, I was momentarily blinded by the glare of the sun. It was also at least thirty degrees warmer above ground than below. We then took another elevator to the top of the tower of the mine shaft, which was about ten stories high. From this vantage point, the entire history of the mine could be clearly seen.
Robinson pointed to a yawning pit, almost 500 feet deep, across the parched earth. It was the original mine. Like all pipe mines, the Wesselton had begun as an open-pit mine. At some point it became too deep to haul out the kimberlite ore profitably. "The only way it could be mined," Robinson said, was "to get the ore out from below."
The half-mile-deep mine I had just visited was below that pit. The continuous belt of buckets dumped the ore from the shaft onto the conveyor belt. At Wesselton, according to Robinson, more than 6,ooo tons of kimberlite ore is brought up the mine shaft every day by this automated equipment. Yet there are only some 1,400 carats of diamonds recovered from this mass of ore. Of these, only about 150 carats are of gem quality. "More diamonds are recovered per ton from the waste dumps than from the mines", he said, pointing to the mountains of kimberlite ore that had been spewed out of the separation plants over the years.
Some of this waste was more than a hundred years old. Diamonds smaller than a tenth of a carat were difficult to sell then , and De Beers had not invested until recently in sophisticated technology for recovering a high proportion of the minute diamonds. Now, however, with factories in India polishing diamonds as small as 1/25th of a carat, there was a ready market for these "small goods."
Even with the "mining" of the old dumps, Robinson admitted that the Wesselton and the other mines around Kimberley were rapidly reaching the point of diminishing returns. He estimated that the De Beers mines in Kimberley could begin to run out of gem diamonds as early as the 1980s. Kimberley might then become a ghost town.
It was here that the diamond invention was devised, and the inseparable connection between Kimberley and De Beers, which is,, still evident when one walks through the town. The zig-zagging streets follow the pattern of the original mining claims. They then end abruptly in an enormous crater that the city literally hangs over. It is about one-quarter of a mile deep and partly filled with rain water, which reflects the buildings on the edge of the city. This abyss is called the Big Hole, and it is what remains of the Kimberley Central mine. This was the deepest open-pit mine ever dug. The ore was lifted out by a system of ropes and pulleys that looked like a giant spider web. Before it was finally abandoned in 1914, it produced over three and a half tons of diamonds. This flood of diamonds not only transformed Kimberley into a city, but it necessitated the creation of a global system for distributing and controlling the sale of diamonds.
The Harry Oppenheimer House is a darkly tinted glass skyscraper that stands in a private park in the center of Kimberley. Built in 1974, the entire building was designed and dedicated to a single purpose: the evaluation of uncut diamonds. The entire total of all the diamond mines and diggings in South Africa and Namibia are shipped here to be sorted, classified and valued. The diamond consignments generally arrive early in the morning in armored trucks, which drive into a concrete bunker in the sub basement of the building. The sealed containers of diamonds are then sent in a special elevator, which makes no intermediary stops, to the top floor. The seal is broken in front of witnesses, and the diamonds immersed in an acid bath to clean off any particles of dirt. After the diamonds are dried by hot-air jets, they are weighed on a highly precise electronic scale. This weight is then entered into a central computer, which will track the shipment as it moves through each stage in the sorting process.
If at any point the weight of the categories it has been divided into adds up to less than the original weight of the consignment, the computer sets off an alarm. This automatically locks the doors of the Harry Oppenheimer House. Only when the missing weight of diamonds is found will the computer permit anyone to leave the building.
Unlike gold or other precious metals, diamonds cannot be assigned a value merely by weighing them. An ounce of diamonds can be worth $100 or $100,000 depending on the quality of the diamonds. Before either a mine-or the South African tax authorities-can determine the value of the diamonds, they have to be sorted into their proper size, shape, color and clarity categories. "By the time we finish, a shipment is broken down into some two thousand different categories. The preliminary sorting is done by a series of ingenious machines that De Beers engineers invented specifically for this purpose. First, the diamonds are passed through a series of sieves. Diamonds that are too small to be cut into jewels are screened out as industrial diamonds. The remaining diamonds are then divided into sixteen different groups according to sizes that range from under to-tenths of carat to over one carat.
Next, within each group, the diamonds are sorted for shape by a series of machines, which by vibrating and twisting are able to separate flat and triangular shapes from the more valuable tetrahedral-shaped diamonds. At each stage in the separation process, the resulting groups are weighed and registered into the computer.
Finally, in this rough sorting, the diamonds are fed into a series of X-ray machines, which by employing different filters are able to automatically sort the diamonds into different colors. The opaque and black diamonds, called bort, as well as the smaller brown and golden diamonds, are separated out to be crushed into industrial abrasives. The diamonds are then again reweighed and sent to the floor below for hand sorting.
Here the gem-grade diamonds are laid out by colors on separate tables, which have been perfectly positioned in respect to the light. A team of sorters,. women in uniformly colored dresses and men in suits, then examine each diamond with a six-power jewelers' loupe to make sure that it is correctly classified. If any of the five sorters disagrees in their opinion, the chief sorter, John Gie, is called in to arbitrate and make a final decision on that particular diamond.
"These are all highly skilled and trained quality controllers," Gie explained to me. All are given periodic eye examinations by De Beers and are tested on their ability to match unsorted diamonds to the De Beers sample set. This set contains some 240 different shades of colors and shapes which serve as a De Beers standard for sorting operations in both Kimberley and London. After every gem diamond is checked for microscopic imperfections representatives of the Diamond Producers Association, which represents individual producers as well as the De Beers-owned mines, are allowed to question any classification they disagree with. In fact this generally is nothing more than a formality.
"A single diamond can be examined as many as ten times," observed Gie. When everyone has agreed on the proper classification of each diamond, the data is fed into the computer. As each diamond is finally weighed, the computer assigns a dollar value to it according to a complex formula. The computer then instantly tallies up the total value of the shipment and credits that amount to the account of the individual mine.
A small percentage of these sorted diamonds are retained at Harry Oppenheimer House and distributed to a select number of local South African dealers. All the rest of the diamonds of South Africa and Namibia are shipped in sealed containers by air to the Diamond Trading Company's headquarters in London. These consignments from Kimberley amounted to some 5,400,000 carats and accounted for about half of all the gem diamonds shipped to London.
I next followed the trail of diamonds from the sorting house in Kimberley to the Diamond Trading Company in London. The trip to the African mines had explained how diamonds were extracted from the earth, but this was only a rudimentary part of the diamond invention. The crucial element in the invention was controlling the supply available to the major diamond cutters and manufacturers, and this allocation took place in London.