AUTHORITIES have temporarily suspended operations at the Veladero gold mine near San Juan, Argentina following a spillage of processing solution onto the leach pad – the base where solvents such as cyanide are added – on 8 September.
Canadian mine operator Barrick said a pipe carrying process solution in the heap leach – the extraction process – area was damaged when it was struck by a large block of ice that had rolled down the heap leach valley slope. A small quantity of the toxic solution, which contains diluted cyanide, left the leach pad as a result.
The San Juan government has ordered the temporary suspension of operations until a safety inspection is carried out.
Sergio Uñac, governor of San Jaun province, said at a press conference yesterday that the closure was a precautionary measure and will continue “until it is determined that there is no risk”.
The company assured that none of the solution from this damaged pipe reached any water diversion channels or watercourses and does not pose any current threat to the health of its employees, or communities and the environment. It also said environmental monitoring of surface and sub-surface water has been increased.
The mine was also shut down in September 2015 when a faulty valve on a pipe carrying processing solution to the heap leach pad spilled around 1,072 m3 of the solution into the Potrerillos River. The company said at the time that cyanide levels downstream near communities did not exceed 0.1 ppm, however the nearest community was located approximately 150 km from the mine. Argentinean authorities fined Barrick approximately US$9m for the incident earlier this year.
Barrick was also fined US$16m by the Chilean government in 2013 for failure to make required environmental reports and failure to carry out work on a promised wastewater management system.
The Veladero mine produced 17 t of gold, worth US$499m, in 2015. The mine has proven reserves of 276.9m t and 16–18 t is expected to be produced this year.
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