Newmont's Ahafo Mine has contained and neutralized, within its mine site, a minor chemical overflow which occurred
at its processing plant, a statement said on Monday.
"The overflow at the processing plant on Thursday, October 8, contained gold ore active processing solution, including sodium cyanide," the statement, signed by Ms. Adiki O. Ayitevie, Regional Manager, Communications, said.
"It was immediately contained with sandbags and neutralized with sodium hypochlorite, a neutralizing solution and cleaned up as per standard operating procedures," it said.
The statement noted that following heavy rains at the mine area, tests were conducted at several downstream locations to ensure the spill had not spread beyond the contained area on site.
It said analyses, by external laboratories, were underway to verify the negligible levels of cyanide so far detected.
Cyanide is only harmful to human beings at levels of 20 part per million (PPM) and above but the statement said that what had been discovered so far, after the overflow, was less than 0.25ppm.
The statement said though the overflow was an onsite incident, stakeholders including the District Chief Executive, people of four hamlets
concerned, chiefs and other opinion leaders were informed about the on site incident and the proactive mitigation measures were taken.
"The Environmental Protection Agency (EPA) and Minerals Commission's Chief Inspector of Mine have also been informed and are currently on site
conducting their investigation."
The statement noted that there was a short-term environmental impact of fish mortality which was also reported by people from the hamlets near the mine following local rainstorms.
It said though currently fishes in the ponds in the drainage flow of the Mine were alive, "we are investigating the potential cause of the fish
mortality and whether this was due to the bleach agent used to neutralize the cyanide solution, residual cyanide or other causes."
"No pollution of the water sources downstream from the plant site has been found. Live fish have been found swimming both below and above the
point at which the dead fish were found," the statement said.
Meanwhile the inhabitants of the impacted hamlets have been supplied with alternative fresh water to use while further investigations are being undertaken to confirm the integrity of their water sources.
"The company is also undertaking its own investigations to fully establish the cause of the incident and help prevent future recurrence," the statement said.