Automated pit dewatering system

Groundwater saturation results in reduced pit wall stability and enhanced safety risks, while an increase in water inflow to the pit reduces mining productivity.

To proactively respond to water ingress, hydrogeologists at Bozshakol have implemented an automated pit dewatering system as a preventative measure. Water seepage into the open pit at the intersection of groundwater streams is reduced using a pumping system in drilled vertical dewatering wells. Eleven dewatering wells have been drilled around the open pit to depths ranging from 80 to 100 metres. Each well is equipped with multistage submersible pumps for groundwater pumping and are connected in an integrated pipeline system which intercepts water inflows to the pit and diverts them directly to the tailings storage facility. All water wells are equipped with automation functionality which allows the hydrogeology team to set water level thresholds for each pump in order to achieve the target level of water drawdown and maximise the stability of the pit walls, as well as optimising the performance of the pumps.

As a result, clean water redirected from the dewatering wells can then be pumped to the concentrators through the return water pipeline system as part of the standard water recycling process at Bozshakol. In 2022, around 1,400 megalitres of water have been redirected from the dewatering system, helping to reduce the fresh water consumption in the production process.

The implementation of the automated pit dewatering system has improved the safety and stability of the pit walls at Bozshakol. Water inflow to the central pit has been reduced by 60% compared with previous years, despite the fact that the mining area has increased by over 70%. Pre-emptive dewatering of the pit through dewatering wells has increased productivity at the pit, as well as reducing overall dewatering costs and reducing the consumption of fresh water at Bozshakol.