An estimated 4.5 cubic metres of processing solution mixed with rainwater spilled from a Victoria Gold heap leach facility July 11.
The company announced the spill in a press release July 13.
According to the press release, employees at the Eagle Gold mine, located in the Mayo region, reporting that water was pooling on the load-out area of the heap leach facility’s pad at 1:30 a.m. on July 11 “during a period of heavy rain.”
Heap leaching involves using a chemical solution to dissolve metals out of mined material. The solution is then processed to obtain the desired metals.
An inspection found that rain water had mixed with process solution and was seeping from the base of the load-out area and onto an adjacent road, the press release says.
The leak was the result of “a combination of a failed solution distribution pipeline, heavy rainfall and the geometry of the berm along the perimeter of the eastern pad, which together led to process solution and rainwater seeping laterally off the pad to the adjacent road rather than to the in-heap pond.”
The seep was contained by 9 a.m., with the solution that leaked out of the containment area estimated to be 4.5 cubic metres and containing less than one kilogram of cyanide. It “did not directly enter a water course and no demonstrable impact to the environment is expected,” according to the press release, and water samples taken downstream the morning of July 11 “have shown no impact as a result of the release.”
Monitoring is ongoing, it adds, and water samples had been sent to an independent laboratory for further analysis.
This is Victoria Gold’s second reported spill this year. In April, the Eagle Gold mine intentionally released about 40,000 cubic metres of water due to snowmelt overwhelming a holding pond. The water in that case contained suspended solids and traces of arsenic and entered Haggart Creek and Dublin Gulch. Initial testing showed that the levels were not “acutely lethal” for rainbow trout in the creek, although sublethal test results are pending.
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