Rehabilitation at closure of a Ag-Pb-Zn mine in Argentina

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SRK News | Issue 58
Mine Closure: Can closure create opportunities?

Ignacio Ezama, Civil Engineer
Camilo de los Hoyos, Senior Consultant

 

This case history is about an old mine in the province of Jujuy, Argentina, which has been producing silver, lead and zinc for 80 years. The mine site is in the arid Puna environment at 3,800 meters above sea level, in a beautiful landscape where tourism, sports and other cultural activities are practiced. 

During operation, tailings were generated and deposited in seven tailings storage facilities (TSFs) which cover an area of about 5 km2. TSF management has been poor; some of the storage ponds have been placed partially on top of older ones, and little care has been taken in protecting the surface of the tailings despite the strong winds that are common in the region. Not surprisingly, wind-blown tailings have spread over an area of 2.5 km2. Topographic depression zones have been filled with sandy tailings. Dunes can be observed all around producing a legacy of environmental, and health and safety issues. 

The current mine management team put forward a strategic plan to improve this situation. Under this plan the most recent TSF was lined; the three largest ponds were covered using a low-permeability liner overlain by organic soil for re-vegetation; and several consulting groups were retained to produce a program to upgrade the whole operation to international environmental standards. 

SRK was commissioned to undertake a pre-feasibility study for the remediation of the area around the TSFs. The challenge was not only to eradicate or minimise health and safety risks, but to optimise the expenditure for environmental conservation and protection. SRK’s recommendations included a revegetation program, the relocation of the windswept tailings, and a prioritisation plan which allows for the progressive remediation of the site aligned with the allocated budget and management expectations. It is expected that the remediation program will significantly reduce the exposure of the mine to scrutiny by the environmental authorities and the risk of future non-compliance with regulators. 

This is another example highlighting the importance of a closure-focused approach at all stages of a mine design and operation, and of the value of adopting progressive closure measures to reduce costs and impact to the environment.

Ignacio Ezama: iezama@srk.com.ar
Camilo de los Hoyos: cdeloshoyos@srk.com.ar

 

SRK Latin America