China Nonferrous Mining (HKG:1258) said it had hired lawyers in Zambia following reports of a court petition asking the company to take remedial steps after a tailings dam incident at the Sino-Metals Leach Zambia copper mining facility, according to a Hong Kong bourse filing Thursday.

Shares of the mining firm gained over 2% in morning trade Friday.

The petition, filed by local residents, is seeking $80 billion for an escrow account that would be managed by the Zambian government for environmental restoration and compensation, as well as $200 million as an emergency relief and health and environmental assessment fund.

The miner said the claims in the petition and widely reported in media were "clearly unfounded," and that it would actively respond and protect its legitimate rights in the process.

The Sino-Metals Leach Zambia incident in February saw the collapse of the tailings dam at the company's copper mine, reportedly releasing 50 million liters of waste into the Kafue River ecosystem which supplies water to around 60% of Zambia's population.

China Nonferrous Mining blamed the collapse on theft and damage caused by heavy rainfall, and said it had taken immediate steps to rectify the leakage. It also highlighted statements my Zambian officials that stated the situation "had basically returned to normal."

China Nonferrous Mining said it had fulfilled its restoration and remediation obligations as required by government directives and compensated individual farmers harmed by the incident.