Monday,November 30,2020 20:57 PM

Kasese Cobalt saves nature

By Vision Reporter

Added 5th April 2004 03:00 AM

For more than 20 years, while Kilembe Mines churned out copper until the late 1970s, it dumped more than one million tonnes of by-product 3km outside Kasese town

For more than 20 years, while Kilembe Mines churned out copper until the late 1970s, it dumped more than one million tonnes of by-product 3km outside Kasese town

By Charles Wendo

For more than 20 years, while Kilembe Mines churned out copper until the late 1970s, it dumped more than one million tonnes of by-product 3km outside Kasese town.

For another 20 years, rain continually drenched the pyrite (by-product) pile. This dissolved the contents and washed them down through Queen Elizabeth National Park and into Lake George.
As the acidic floods meandered towards Lake George, they burnt vegetation and left bare soil through a stretch covering 12km of the game park. The soil too became acidic so that plants could not grow.

Today, the barren strip of land is still visible. However, Kasese Cobalt Company Limited (KCCL) has blocked further flow of acidic floods into the game park, and Makerere University scientists have demonstrated that the barren land can be made grassy again. “We have built a dam to make sure the contaminated water does not go into the park but some people thought we just don’t want them to see what we do here.

They thought we were shielding something,” says Andrew Lumbuye, the KCCL Human Resource Manager.
Moses Mugabi, the company’s process manager, explains how they turn trash into cash while solving a serious environmental problem that Kilembe Mines created between 1956 and 1977.

During the 1990s, French experts assessed the heap of copper processing by-product and found that it had enough cobalt for commercial exploitation. In 1999, KCCL was set up and it begun mining cobalt for export. “Kilembe Mines was mainly interested in copper. Part of the waste was pyrite. In that pyrite we find other metals such as cobalt and nickel,” says Mugabi.

Everyday, workmen at Kasese Cobalt shoot water into the pyrite pile, at a very high pressure. The result is a porridge-like stuff, which flows through a sieve into a system where a series of reactions release cobalt, nickel and copper metals.

When The New Vision visited the cobalt plant on March 23, more than 20 tonnes of cobalt were ready for export. The plant had partially closed last year because cobalt prices had plunged. However, production resumed early this year after world cobalt prices shot up again. The mineral is on demand in developed countries where it is used in making jet engines, magnetic materials, cell phone batteries, colours and other hardening metals. One unique thing about the Kasese plant is that it uses bacteria to extract cobalt from the pyrite. Three species of bacteria; Thiobacillae ferrooxidans, Thiobacillae thiooxidans and Leptospirillum ferrooxidans feed on the pyrite to set the metals free.

The system is referred to as bioleach. French scientists carried out an experiment and proved that these bacteria could be used industrially to extract cobalt from the pyrite.
“A similar process has been used for mining other minerals but this is the first time it is used for cobalt. Because they did the research here they decided to do it here first,” says Mugabi.

As part of the company’s environmental policy, the wastewater is treated thoroughly then slowly released towards a river. A stone’s throw away from the cobalt plant, KCCL constructed a wetland with local marshy plants that further clean up metal elements that might have eluded the treatment. The plants also suck up water and reduce the amount of wastewater that drains into the river.

“We have very strict conditions to make sure we do not pollute the environment. No wonder we won environmental awards,” says Mugabi.
The company last year scooped the Elly Tibakanya Africa Environmental Award.
Evaristo Byekwaso, the chief environment officer, says they constantly test ground water to ensure that it doesn’t get polluted as a result of the cobalt processing activities. Apart from preventing pollution, the company has also been working with Makerere University experts to find out ways to re-vegetate the barren land that was burnt by the acidic wastes from the by-products of copper mining. They carried out an experiment to neutralise the acidity of the barren soil, then plant grass.

They neutralised the acidity by pouring lime on the soil. It worked well, but they were able to re-vegetate only a small area.
Byekwaso says they have proved that it is possible to re-vegetate all the barren land. Now it is up to the Uganda Wildlife Authority to do it. “Government can take a decision on that,” he said. “You have to neutralise acid along the entire stretch and then re-vegetate it.”

Kasese Cobalt saves nature

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