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Mercury in mining: A poisoned chalice

In the quest to eke out a living, artisanal gold miners in Uganda are risking their lives and slowly poisoning every living thing around them.

A Mubende miner displays mercury (Photo: C. Musiime)

A Mubende miner displays mercury (Photo: C. Musiime)

Three years ago, the most serious health and safety issues associated with gold mining in Uganda were respiratory problems caused by continuous inhalation of dust and the occasional collapse of a tunnel, sometimes trapping unfortunate miners underground.

The miners relied on rudimentary technics to extract as much gold as they could, until a new, seemingly magical substance was introduced, reportedly from Kenya. The miners in Busia, Eastern Uganda, learnt from their counterparts across the border that by adding a few drops of mercury in a gold dust solution, they were able to harvest three times the amount of gold they had been retrieving.

Word spread about this ‘invention’ and it was just a matter of weeks before it reached most mining communities in Uganda.

Today, it is almost unimaginable for an artisanal miner to run a mining operation without the aid of this silver magic portion. In fact, those miners that are new to this business cannot imagine how their colleagues managed to do without it.

But, with this lucrative practice also comes dreadful health consequences.

According to Dr. Gyagenda Joseph Ogavu, a physician at Nsambya hospital, mercury is a heavy metal that is not easily absorbed by living organisms, including humans.

“This mercury will accumulate in the kidney, liver, skin and lungs causing permanent mental disability and a range of other conditions,” he told Oil in Uganda. “If it gets to the lungs, it is very dangerous because it can get to the blood and easily destroy the covering of the nerves.”

Studies have also associated human exposure to mercury with emotional instability, insomnia, neuromuscular problems, infertility, headaches and a host of other sicknesses.

But because most of these ailments are cumulative, only becoming evident in the medium to long term, most miners have chosen to ignore them, partly because they have no alternative employment, but also because most do not appreciate the gravity of the problem.

“These miners do not want to hear that because they think one just wants to deceive them and use the mercury themselves,” explains Edward Ssenfuma, the Chairman of the Mubende Artisanal and Small Scale Miners Association.

Mercury in mining

While mining, gold-rich lumps of rock and soil are excavated from underground pits and brought to the surface for ‘refining.’ Middle men buy these rocks and crush them into fine powder. Part of this powder are gold particles so fine that they cannot be seen with the naked eye. The dust is mixed with water in a basin and stirred to form a muddy solution.

And this is where mercury comes in.

“If you are to use half a basin of water, you will need to mix it with just one bottle top of mercury and stir to form an amalgamation,” Ssenfuma explains.

Like a magnet, mercury effortlessly attracts almost all the gold particles in the powder, isolating worthless dirt from the precious metal.

Normally the work for the women in the mining camps, sacks of dust are subjected to this strenuous slow process until the drop of mercury has accumulated enough gold to form a tiny silver-coloured gold ball the size of a pea. No safety gear is worn during the process. The discharged waste water drains into nearby streams or swamps, introducing mercury traces into the aquatic environment.

A woman displays a piece of impure gold after the 'washing' process. To purify it, its heated using a burner to remove the mercury.

A woman displays a piece of impure gold. To purify it, its heated using a burner to remove the mercury. (Photo: C. Musiime)

The gold ball is then placed on a spoon and burnt using a gas-powered burner to remove the mercury impurities and the outcome is an even smaller ball of pure gold. This is possibly one of the most deadly stages because the fumes released from the burning process are inhaled by the entire camp.

Normally, three grams of mercury are used to produce one gram of gold. The mercury is sourced from the black market in Kampala and a kilo reportedly costs four hundred thousand shillings ($150).

In a mining camp that Oil in Uganda visited in Mubende District, a gram of mercury was being sold one thousand shillings (less than half a dollar).

“In 2012 when we had just started using mercury, a gram was sold at ten thousand shillings (about 4 dollars),” noted Kibirige.

For the miners, the cost of mercury is a negligible price to pay considering that a gram of gold will fetch at least eighty five thousand shillings ($32) in the camp.

Intervention

According to Vincent Kato, a Principal Geologist at the Department of Geological Survey and Mines, government has developed a strategic plan to promote environmentally sustainable mining.

“The Ministry trained small scale miners  at Kisita mines (Mubende District) on better  mining methods which are environmentally sustainable,” he said, adding that the government has also shared information on the dangers of mercury use.

Mr. Kato revealed that government plans to introduce mercury retorts that will allow the use of mercury in a closed loop, with minimal exposure. The retorts also allow the recycling of the mercury, keeping the quantities low.

A retort is a cast iron or steel container with an airtight cover that does not allow any fumes to escape during the burning. The fumes can only escape through a tube and are condensed by an adjoining water container.

He added that the technology is currently being used in Tanzania, Ghana and Mongolia.

A ‘better’, deadlier alternative

Meanwhile, some shrewd miners have moved beyond mercury and started to use an even deadlier compound-Cyanide.

“There is a mine where people are using it illegally and they are bringing it from Tanzania,” revealed Ssenfuma.

“Now the problem is that Cyanide is better but very poisonous. With mercury, you will get three times the gold (compared to non-mercury methods) but with Cyanide, you will get ten times more,” he said.

Cyanide is acutely toxic to humans and other living organisms even at very low concentrations. But despite its lethal characteristics, artisanal miners are likely to opt for short term gains from their hard labour. The future, like some say, will take care of itself.

Report by Beatrice Ongode

editor@oilinuganda.org