Jwaneng cornerstone of Botswana’s future — Operation will soon be De Beers’ most technically advanced mine

Jwaneng, Botswana — Pula, the Setswana word for rain, carries a heavy load of connotations in this arid country. It means prosperity, good fortune, and even prudence.

Pula has a record of coming down from the skies in most parts of the world, but here it comes up from below; in modern Botswana, prosperity is closely linked to the diamond industry and the major producer, Debswana Diamond.

De Beers Consolidated Mines (DBRS-Q), through Swiss-based De Beers Centenary, owns a 50% interest in Debswana; the Botswanan government holds the other 50%. Debswana operates three mines, one at Jwaneng, 120 km west of the capital, Gaborone, and two others, named Orapa and Letlhakane, situated roughly 400 km north of Gaborone.

The Northern Miner recently visited Jwaneng, which produced 11.1 million carats in 1996 and 12.6 million carats in 1997. Orapa, which produces about 5.5 million carats annually, is expanding, and should produce 12 million carats in 2000; Letlhakane produces just under 1 million carats a year.

The mine life of Jwaneng’s open pit is pegged at 30 years, implying that after excavation to an ultimate depth of 600 metres, the mine will have produced another 240 million tonnes of ore grading 130-150 carats per 100 tonnes. Jwaneng stones have been estimated to have an average value of US$100 per carat; combined with the high grade, this makes Jwaneng one of the richest diamond mines in the world.

Three kimberlite pipes make up the orebody, which coalesces into a single large diatreme-breccia body near the surface. Unlike many southern African pipes, there is no preserved tuff crater. The three pipes continue below the designed floor of the pit, but there are not enough deep drill holes to assess the resource at depth. Geologists outside the company have estimated that if the pipes continue to a 1,200-metre depth, Jwaneng could contain 740 million tonnes of ore, though perhaps not at grades comparable to those found in the open pit.

Jwaneng operates its pit with 85- and 177-tonne diesel trucks and electric excavating shovels. Drills are also electric; Jwaneng management has made a conscious choice to go with electrical equipment wherever possible, to take advantage of low maintenance costs and a reliable supply from the national power grid.

With a score-and-a-half projected pit life in the bag, Debswana has not developed even hypothetical plans for a move underground.

The most closely comparable situation is De Beers’ Finsch mine, 140 km west of Kimberley, South Africa. There, the pipe is being mined by open stoping that retreats from the walls of the existing pit; the next phase of mining will see kimberlite below the pit floor removed by retreating block caving.

“We’ll naturally take lessons from Finsch,” said Derrick Moore, general manager at Jwaneng.

Jwaneng’s orebody, called DK2, was discovered in 1972 by an indicator mineral survey. It was moved to feasibility in 1978 and went into production in 1982. Those were lean years in the diamond industry, and the Botswanan government, convinced that maintaining the price was important, helped to fund De Beers’ Central Selling Organization’s plan to stockpile Botswanan diamond production. In exchange for its backing, the government got a large minority shareholding in De Beers and two seats on the boards of De Beers Consolidated and De Beers Centenary.

Botswana — one of the few countries in sub-Saharan Africa to have remained a functioning democracy since gaining independence — has seen the initial protection of its diamond industry pay off handsomely. Diamond production accounts for 70% of gross domestic product, and is the country’s biggest foreign-exchange earner. The next-biggest source is the interest on diamond earnings. It is perhaps too obvious to note that the government runs a budget surplus.

Armed with diamond revenue, Botswana has raised its public education standards and developed a reliable infrastructure. Moore is impressed by the advances in educational standards: “The government has built a lot more schools over the last ten years, and more children in Botswana are able to go to school. We can see the results.”

For the older generation of mine workers Debswana offers free adult basic education during working hours; as a result, the company expects to have a fully literate and numerate workforce in another three years.

The educational programs are vital to Debswana’s “localization” policy, which ultimately aims to place Botswanan nationals in most of the company’s top positions. Debswana also sponsors local students who aspire to tertiary education, either in Botswana or abroad.

As the diamond market rebounded in the 1980s, Jwaneng began its career as a money spinner. By 1993, the centre of gravity of the Jwaneng pit had descended far enough that the mine added an in-pit crushing plant with a daily capacity of 30,000 tonnes. The original crusher on surface is still used to crush stockpiled ore, while another crushing plant is under construction at a deeper level in the pit. When that new crusher goes into service this year, the present in-pit crusher will be overhauled and disassembled, then will “leapfrog” the second crusher to be rebuilt at a still-lower level.

Broken ore is reduced to 150 mm with a gyratory crusher, then drops to a conveyor that runs directly to the plant. Jwaneng’s plant has a conventional diamond-recovery layout, with secondary crushing, two stages of dense-medium separation with a grinding stage in between, and final recovery by X-ray fluorescence. Concentrates then go to the sort house, where the diamonds are separated manually by sorters using glove boxes. The concentrates and the separated diamonds travel from one vault to another in enclosed pipeways to defeat theft.

Process water and slimes from the plant are pumped to a series of slimes ponds, where the decant water is recovered and returned to the process.

Water effluent is of no concern, since Jwaneng is a net water consumer and process water is recovered wherever possible. A 30-well production field about 50 km from the site provides the mine with fresh water.

Like most diamond mines, Jwaneng’s major environmental concern is the disposal of inert, fine rock waste. Currently, mill tailings are tipped to build large hills that will ultimately be stabilized by revegetation.

The next major project at Jwaneng is called “Aquarium,” a nod to its two components — the Completely Automated Recovery Plant (CARP), and the Fully Integrated Sort House (FISH). Increased automation of the separation processes and elimination of human contact in the sort house are the touchstones of De Beers’ security effort; plant and sort house workers can better resist approaches or threats from illegal diamond traffickers when they can protest that they have no access to diamonds in the facility.

Aquarium is scheduled to be complete in 2000, and will be the first fully hands-off plant in the De Beers stable.

Other security measures are more relaxed than at other De Beers operations.

The Debswana mines have no legal right to X-ray employees or to do invasive searches; mine manager Moore said that management does not like the idea, and it would not be accepted by the workforce in any event.

Moore believes diamond theft is increasing, but is still at a much lower level than comparable operations in other countries, thanks to a strong culture of honesty at Debswana. “It’s increasing, and there may be South African influence,” he said. “We know there have been quite a few South African people involved [in illegal diamond buying] . . . I know many of our people are being approached and many of them tell our security.” When the Miner visited Jwaneng, the most thorough end-of-shift search included emptying boots and pockets, and rewinding film in a camera; it was a far cry from routine x-raying and frisking at other mines.

Debswana’s sorting and valuing subsidiary, Botswana Diamond Valuing Company (BDVC), buys the production from all three of Debswana’s mines, sorts the diamonds into 5,000 separate categories, and sells them to the CSO.

Rough arrive
s from the mines in locked trunks and is promptly inventoried and sized. An initial automated sorting stream separates the diamonds by shape, quality (density of inclusions), and finally by color; the lots that come out of this initial process then go to sorters for manual classification.

Color and quality are the main determinants of price, but most manufacturers will choose their stones by shape. Most cutters tend to specialize in a few different rough shapes — from easily cuttable octahedra to more troublesome irregular and flat stones. Well-shaped stones will lose about half their weight in the cutting process; irregular ones will lose much more.

Rejections from the sorting process generally go to cutting and polishing factories in India, where low labor costs permit manufacturers to tackle small and poor-quality stones that require large labor inputs. Larger rejects may be bought by higher-price cutters in Tel Aviv, Israel or Antwerp, Belgium who are prepared to speculate on low-quality stones in the hope of producing expensive cut stones “hidden” in lower-quality rough; the risk these buyers take lies in the high ratio of waste on cutting that is characteristic of poorly shaped stones.

Security risks increase at the hand-sorting stage, so BDVC has developed a body of practice that heightens security of the goods. BDVC’s building provides everything that sorters need during the work period so that trips outside the building are kept to a minimum. Each batch of samples to be hand-sorted is weighed whenever it is handled, leaving a paper trail that would instantly point to any loss. Video cameras monitor the sorting process and tapes are retained until the batch is sold by the CSO, usually two to three months after it arrived at BDVC.

Still, BDVC’s security experience has been a good one, mirroring the situation at Jwaneng. The audit process that goes along with handling protects the goods, but so do trained and trustworthy sorters.

Ben Ratsoma, manager of the sorting floor that handles the largest diamonds, points out that the procedures themselves are only half the effort; the other half is building a long-term relationship with the employees. Said Ratsoma, “We can’t afford to trust people just 99%.”

Personal knowledge of the sorters and consistently stressing the importance of security reassure BDVC that sorting staff won’t be tempted — or, more likely, coerced — into theft.

Debswana’s venture into diamond cutting, the Temame cutting plant, has not been the same kind of success as the sorting operation. Temame loses money, as do the country’s two other cutting plants, Mabrodiam and Lazar Kaplan.

“We often say to people, ‘If you want to understand diamond cutting you have to go to India,'” said Louis Nchindo, BDVC’s managing director. In competitiveness, Nchindo said, “the Indians set the benchmark.” Indian cutting operations rely on family connections, with 90% of the work done by small cottage contractors. Cutting and polishing add value almost completely through labor inputs, and the low cost of labor in India — compounded over the last 25 years by a steady devaluation in the rupee from US33cents to US2.8cents — makes other cutters uncompetitive on all but the largest and best-quality stones.

Other advantages stack up. For example, Indian importation laws give owners of cutting plants a yearly duty-free allowance of 20% of the value of their exports, which can be imported in any form; this means the proprietors can bring in dutiable goods such as cars, machinery or computers and resell them, essentially subsidizing the cutting operation.

The rise of the Indian industry has affected most diamond cutting centres.

“When I first joined the company, there were 20,000 cutters in Antwerp,” said Nchindo. “Today there are less than 3,000 — that’s 20 years.” He is pessimistic about the chance of a diamond cutting industry blossoming in Canada, too. “That would be one quick way to diminish the value of your diamonds.”

The Botswanans make no secret that they think that would be a waste of good pula.