Tailings management: A simple way to increase water reclaim

摘要

Cia Minera Dona Ines de Collahuasi (Collahuasi) is mining the Ujina copper deposit since late 1998, feeding with copper sulfides the concentration plant, whose nominal process capacity was 60,000 tons of dry mineral ore per day (tpd). Starting in 2004, it was decided to feed the concentrator plant from the Rosario ore deposit. As part of the transition between the Ujina and Rosario ore deposits, Collahuasi decided to increase mine production and processing from 65,000 tpd (current production) until a final treatment capacity of 120,000 tpd was reached. This expanded production meant an increase in the use of fresh water, resource that is highly scarce in the area and very environmentally sensitive. As a way of reducing this greater demand for water, Collahuasi considered modifying the process and tailings deposition, trying to minimize water losses and maximize the impoundment's rate of reclaim. This modification included the relocation of the tailings pond, which had to be done without interrupting the impoundment's nor the water reclaim operation, a task without precedent for an operation of this magnitude in Chile. This paper describes the modifications performed in the tailings deposition scheme, the increase in the water reclaim rate obtained during the first months of implementation, and its comparison with projected values. This project of pond relocation as well as its implementation is an excellent demonstration of a successful team effort between engineering and operations meeting a established objective.