Paladin Energy has reported a rupture in the liner of the plant run-off tank at its Kayelekera mine in northern Malawi when it suffered minor storm damage, allowing 25mm of rain to fall at the site.
The rupture has resulted in the release of up to 500m³ of material in to the bunded areas of the site and up to 0.05m³ may have overtopped one of the containment bunds.
Following discovery of the damaged tank, the company initiated a sampling programme to analyse water from within the local stream system to confirm whether contamination has occurred.
The announcement comes two days after the company refuted reports it had been discharging toxic waste from Kayelekera mine into a local river.
In response to media reports, Paladin released a statement saying that: "These reports are sourced from local non-government organisations (NGOs) and individuals openly hostile to the company and contain numerous blatant falsehoods and misleading statements, intended to cause alarm and distress in communities living in the vicinity of KM and the local river system.
The statement added that there would be no human or environmental hazard arising from the release of treated water, and that legal action would be taken unless allegations stopped.
Following the incident, Paladin is considering employing the controlled release of surplus water into the local river system to avoid unplanned and uncontrolled discharge of run-off water held in storage ponds. The company has modified a section of the plant at the mine to allow treatment to meet Malawi and internationally recognised discharge standards.
In recent months, the company carried out onsite test work and successfully treated water to meet the World Health Organisation drinking water guideline for uranium content.
Relevant Government of Malawi agencies have also reviewed the process, which will be constantly monitored when the water treatment and release process re-starts.