Tahoe Resources has reported what appears to be attempted theft at its La Arena gold mine after discovering five “significant” holes cut into the top of the pregnant solution pipeline at the operation in La Libertad, Peru.
The cuts on the pipeline that transfers solution from leach pad 4B to the pregnant solution pond caused discharge of solution from the pipeline into a storm water collection pond designed to discharge clean water into the nearby Sayapampa Creek, which runs through part of the property.
Tahoe said: “Based on a preliminary internal investigation, the company believes that in an apparent theft attempt, holes were cut into the top of the pipeline in order to place bags of carbon inside of the pipeline to absorb gold from the solution. One of the bags of carbon blocked the pipeline and the solution sprayed from the hole onto the top of the raincoat sitting above the pipeline.”
Subsequently, the solution flowed across the raincoat into the storm water collection pond.
The company’s initial investigation estimates around 600 cu.m of pregnant solution may have flowed into the Sayapampa Creek via the storm water management system.
“Upon identification of the discharge, the company immediately initiated our emergency response protocols including conducting extensive inspections of the surrounding areas from the operation and assessing the potential impacts to the communities and environment downstream,” Tahoe said.
Tahoe reported the incident to the Agency for Environmental Assessment and Control (OEFA), the Ministry of Energy and Mines, the police, the public prosecutor and surrounding communities. The police and OEFA were both expected on site on August 29 to conduct investigations.
“Given that the impacted pipeline is a gravity-flow line and the holes are at the top of the pipeline, the company is able to safely maintain solution flow from pad 4B without leakage into the storm water management system now that the obstruction has been removed,” Tahoe said.
“The company expects that the damage to the raincoat and pipeline will be repaired over the next several days, once all relevant authorities have conducted their initial investigations. Equally important, the company is already in the process of addressing the contamination to the storm water management system. As a result, the company does not anticipate a material impact to production at this time.”
A full internal investigation and review of security procedures will be conducted in order to avoid and prevent future incidents, Tahoe said.
The La Arena heap leach operation was previously slated to produce 160,000-185,000 oz of gold in 2018 at all-in sustaining costs of $950-1,050/oz.