The most impressive sight when visiting KCM’s Konkola Deep copper mine on the Copperbelt isn’t the sophisticated equipment and machinery, but the vast quantities of water gushing out from underground.
About 450 million litres of water are pumped to the surface by KCM every day – that’s enough to fill 180 Olympic-size swimming pools.
As the water bursts forth through huge pipes and rushes down purpose-built channels in an impressive display of noise and foam, Konkola Deep feels more like a water-treatment plant than a mine. The underground water first passes through a series of special sumps for settling and sedimentation. By the time it is pumped to the surface, it is clean and clear. The bulk of the water is discharged into the nearby Kafue River. However, some of it is recycled for operational purposes (e.g.: drilling), and some of it is supplied free of charge to the water utility company, Molonga Water & Sewerage Company, for supply to the community.
Other Copperbelt mines such as Mopani and Lubambe also have to contend with underground water, though in lesser quantities than those of Konkola Deep, which is one of the world’s wettest mines. The water comes from deep underground aquifers which stretch for many kilometres in all directions, and is an integral part of the geology of the area. To get at richer grades of copper, you have to go deeper; but as you go deeper, you encounter more water. It has to be pumped away before the miners can access the ore body.
Impressive though the daily water spectacle is, the mines would far rather do without it. The water represents a major cost which makes every tonne of finished copper more expensive.
“The water is a cost which makes every tonne of copper more expensive”
Massive underground pump stations have to be built, consisting of kilometres of piping, dozens of pumps driven by powerful electric motors, and extensive electrical and other infrastructure. And it all has to be staffed, operated and maintained.
In the past few years since Zambia started to experience erratic electricity supply, the mines have had to invest in extensive back-up generator plants to keep the pumps going in case the power fails. After an outage a few years ago flooded parts of its underground operations and trapped miners underground for several hours, KCM constructed a multi-million-dollar, state-of-the-art diesel generator plant. The facility consists of a bank of gargantuan diesel generators fed by a storage tank constantly topped up by 1½ million litres of diesel fuel. This is back-up capacity on an industrial scale, and the 24 MW plant can generate enough electricity to power more than 20 000 homes.
Underground water is one of the many challenges Copperbelt mines face, but it hasn’t stopped them expanding their operations and drilling deeper underground. The shaft at Konkola Deep has already reached its target depth of 1 500 metres, and the mine is ramping up to full production. At nearby Lubambe mine, underground water was encountered at far shallower depths than had initially been anticipated, but it hasn’t stopped the mine from taking the necessary – and expensive – measures to deal with it.
Underground water is something one has to live with on the Copperbelt, and the mines just have to suck it up – no pun intended.