SOLWEZI, ZAMBIA – Pollution of the natural environment is generally viewed as an inherent consequence of the complexity of large-scale commercial mining, which often negatively affects communities when harmful emissions find their way into the environment.
To minimise the negative impact on the environment, First Quantum Minerals’ Kansanshi Mining Plc. has established a pioneering water recycling system using cutting-edge technology to prevent effluent from getting into external water bodies.
Kansanshi Mine Environmental Manager Arnold Malambo says there are three main sources of contaminated water on a mine site – process water, mine drainage and surface run-off.
“Water is a very important resource in mining. Without adequate amounts of water, your processing can be affected,” he explained.
Water used in mineral processing will inevitably come into contact with metals. Generally, metals, particularly those dissolved in water, are not environmentally friendly. Any water that a mine discharges into the environment must meet strict standards set by the Zambia Environmental Management Agency (ZEMA) to avoid it becoming a pollutant.
Mr Malambo notes that meeting minimum compliance standards regarding environmental pollution is a common problem for mines the world over.
“What we have done better than other mines is that we have been able to maintain a zero rate of discharge into the receiving environment,” he said.
In 2015 Kansanshi developed a rigorous water recycling system to ensure contact water does not reach the natural environment even after it had been treated in the sedimentation ponds along the mine’s water treatment system.
Any incidental overflows from the process plant go through a series of sedimentation points where solids are settled before going to a final pond at the compli-ance point. Here, the treated water is pumped back to the process system for reuse through a 1.7 kilometre long pipe.
The mine, which is also Zambia’s largest taxpayer, has installed an automated monitoring system to ensure the effluent remains within ZEMA’s minimum re-quirements. The system also has an early warning system that generates ‘SMS’ notifications to Environmental and Process staff if water levels approach a critical point, to avoid pond overflows.
“Over the last three to four wet seasons, we have only had no more than five instances when we discharged effluent into the environment via our discharge point licensed by ZEMA. This is a rare fit for a mine not only in Zambia but across the globe, especially considering that heavy rainfall tends to increase the amount of water in the holding ponds hence the need to discharge,” explained Mr Malambo.
“The benefit of this is that we have improved our water resilience index in that we are drawing less water from surrounding streams thereby making more water available to other users. If you disturb an area’s aquatic ecosystem through pollution, you inevitably affect the human population that depends on it.”
Zambia Environmental Management Agency Principle Inspector for North Western Province, Morrison Songwe said the general water quality in Solwezi in the context of industrial pollution was good.
“We have done a number of random inspections at FQM, Kansanshi mine looking at their water handling system and our results show no evidence of pollution from the mine in the area’s surface water. This is the water in Kifubwa and Solwezi River as well as Mutanda stream” said Mr Songwe.
“There is an area where they have been licensed to discharge water into the environment and this area showed zero discharge during each of our inspections. Further, we also found no evidence of effluent in the mine’s holding pond from which they are supposed to discharge. We can, therefore, safely say there is zero discharge from the mine going into the environment.
However, further work needs to be done to understand what is going on with underground water, he added. There is ongoing work earmarked to be undertaken soon to iron out the areas of improvement. This work will be carried out by various stakeholders including water affairs, North Western Water Supply and the mines in the area.”
Mr Songwe described FQM’s water handling system as a standard for other mining companies to follow.
“This system is the standard that other mines should follow. We would like to encourage them to come and have a look at how FQM is handling water from tail-ing storage facilities, the processing plant and storm water to ensure nothing goes into their surrounding environment,” he concluded.
Mr Malambo noted that “The initiative we undertook as FQM to ensure we remain a zero discharge mine demonstrates our ethos of being Bolder, Smart, Driven and Together.
It is the togetherness of all players involved that has enabled First Quantum Minerals to achieve all these milestones and protect surrounding communities from industrial water pollution. To us, water stewardship is one of our biggest priorities.”