WATER MANAGEMENT discharge of the water to the nearby Red River. If successful, the trial will be an important next step for Strongbow Exploration, which plans to re-open the mine.
SPS has successfully completed many mine water treatment plants, designs and feasibility studies in the UK, Greece, the Slovak Republic, France, Canada and Australia. These include Wheal Jane, also in Cornwall, one of the largest active mine water treatment projects in the world, which over the last 14 years has involved treating over 100 million m 3 of water. SPS also designed the Dawdon mine water treatment plant for the UK Coal Authority, which won the 2010 Eddie Award for the best water treatment plant in the UK. Last year, it finished a turnkey contract to design, construct and commission a water treatment system for Wolf Minerals’ new Drakelands tungsten mine, near Plymouth in Devon.
Commenting on South Crofty, Chris Bullen, SPS Technical Manager said:“ It is great to have been chosen to work on such an important and high profile project. We have a long history not only of working with mines but also of this region, we understand the local geology and have consulted heavily with the Strongbow team on the best way to dewater the mine. This initial trial phase is very important; it will not only show that the required environmental standards can be met, but will also demonstrate the viability of the whole mine.”
The trial will see SPS’ s High Density Sludge process treat 18 m 3 / h of mine water over the next two or three months. This will not only provide performance data to support Strongbow’ s discharge consent permit application but will also be used in the design of the full-scale plant; if the trial is successful, the company would like to scale things up, to treat and discharge up to 25,000 m 3 / d of mine water. This will enable the mine to be dewatered over an 18-24 month period ahead of reopening. The South Crofty tin project area covers 1,490 ha, and includes 26 former producing mines.
Avoiding contaminants
In South Africa’ s increasingly water-scarce and environmentally regulated mining industry, BME’ s emulsion explosives help keep nitrates out of mine water – preventing possible groundwater contamination and allowing optimal recycling of water on site.“ Recent international studies suggest that up to 28 % of nitrates from traditional ANFO explosive can leach into water draining through underground mine workings during a blasting campaign,” said BME Operations Manager Neil Alberts.“ These levels can be reduced to as little as 2 % by applying best practice, but the long-term solution lies in explosives that do not release nitrates into water sources.”
As the pioneer in cold emulsion explosives in
South Africa, BME has evolved this technology to new levels over the past three decades, said Alberts.“ Among the characteristics of our emulsions range is its excellent water resistance, which means that the explosive material does not dissolve readily in water,” he said.“ This reduces the amount of nitrate leaching to negligible levels.” Tests conducted by BME indicated that, after being immersed in water for a month, its emulsion released only about 0.7 % of its nitrate content.
High levels of ANFO wastage – mines typically accept that about 30 % of ANFO delivered to a blast site is not consumed in blasting – suggest that it may be a contributor to nitrate levels in water passing through mine workings.
Another advantage of these emulsions is that no oil is released, ensuring that water contamination by oil is also prevented; both the nitrate and the fuel phases of the mixture are bonded tightly by the emulsifier.“ BME emulsions have already contributed to environmental sustainability on mines by incorporating and consuming previously used oil in its emulsion products, helping mines to dispose of these liquids safely and costeffectively,” he said.“ The way we have evolved the matrix also ensures that no oil is released when our emulsion comes into contact with water at the stope face.” IM
MINPRO International
Specialists in MIneral processing Equipment