Por: Edwin Cereceda Espinoza, Jesús Guerra Molina y Edgard Atencia Daga, Sociedad Minera El Brocal.

Abstract

Mining is currently in a scenario where resources have lower grade content, added to the current situation of the country with the economic slowdown and inflation. In view of this, it is crucial to look for improvement opportunities to make mining profitable by optimizing the process in order to reduce operating costs. In particular, medium-sized mining contributes with a Cu production of 12.5% of the national total, which translates into 304,828 fine tons/year of Cu.

At the Colquijirca unit, Sociedad Minera el Brocal SAA, as part of the improvement plan, the Mine to Mill project has been incorporated, a methodology that has provided good results in surface mining processes.

In order to provide a solution, an analysis of the initial state is carried out, seeking synergy between the areas of Mine Operations, Maintenance and Concentrator Plant, whose objective is to obtain a more fragmented and homogeneous material, which implies a greater amount of fines, lower crushing costs, higher hourly flows and an increase in the tonnage treated.

In order to apply the methodology, we worked with the database of the mine-plant fragmentation process (run-of-mine), generating a model and its subsequent application.

Prior to the application of the Mine to Mill methodology, the actual fragmentation was 9 in. resulting in a suboptimal crushing and grinding feed size with a mine-to-plant comminution process cost of $12.4/ton. It was decided to use the Mine to Mill methodology to improve the comminution circuit obtaining a fragmentation size of 4.5 in. and a process cost of 10.2 $/Ton. The milling circuit went from 320 tph to 400 tph, a 10% increase in efficiency and a 60% decrease in hours of rock breaking, cost of equipment damage and spare parts, controlling the dilution of the ore. This has resulted in savings of US$ 660K per month.