High Tonnage Surface Stacking Impediments to Implementation

Abstract

Water is a significant issue in the Atacama desert, and at a variety of mining locations worldwide. Maximizing water recovery makes sense both economically and environmentally. Surface stacking of tailings would appear to significantly improve water recovery for a limited additional capital expense. An additional benefit is extending the tailings impoundment life. However, even though surface stacking of tailings would appear to be both feasible and reasonable, the number of mines practicing this method is relatively low. So why hasn't this technology taken off in a dry climate like the Atacama? A number of studies have been done looking at applying these methods to handle very high tonnages, but none of them have gone ahead. This paper will consider some of the reasons why and the barriers to implementing these projects.https://papers.acg.

Sustainable Management of Thickened Tailings in Chile and Peru: A Review of Practical Experience and Socio-Environmental Acceptance

“…The coarse tailings are used for hydraulic filling of underground mines and the fine tailings are disposed of on the surface using paste tailings technology. The concentrations of solids by weight (Cw) obtained for the tailings thickened in the DCT thickener reach values of the order of 70% [45,73]. The paste tailings are pumped by pumps and pipes to the high points of the El Platanal and El Limonar deposits, where they are discharged from a series of spigots, which allow it to reach a deposition slope of the order of 3.0 to 4.0% (Figures 59-61) [45,73].…”

“…The solids concentration range of paste tailings for surface disposal is from 71 to 74% solids by weight (Cw), with peaks of 76% solids (Figure 57) [44,72]. The Cobriza Mine is located in the district of San Pedro de Coris, province of Churcampa, department of Huancavelica, on the left bank of the Mantaro River, in the eastern highlands of Peru, on the eastern flank of the Central Cordillera of the Andes, at 2300 masl [45,73].…”

“…The mineral concentrator plant was designed to process 3,000,000 tons/year of copper ore with a nominal feed rate of 9000 mtpd, and the froth flotation process is carried out there. The ore previously goes through a crushing and grinding process-classification [45,73].…”

“…The concentrations of solids by weight (Cw) obtained for the tailings thickened in the DCT thickener reach values of the order of 70% [45,73]. The paste tailings are pumped by pumps and pipes to the high points of the El Platanal and El Limonar deposits, where they are discharged from a series of spigots, which allow it to reach a deposition slope of the order of 3.0 to 4.0% (Figures 59-61) [45,73]. Due to the complex topography of the site and the lack of space to deposit tailings in a deposit, Cobriza decided to mechanically remove the tailings deposited in paste form in the El Platanal and El Limonar deposits with a hydraulic excavator and dump truck to be transported to a new deposit called Chacapampa and place them in compacted layers similar to a dry stack deposit.…”

Dewatering to higher densities - an industry review

“…Over the last 10 years engineering firms have come to accept and begun looking at using the new capabilities. The shift in thinking has been going on for a while but has only recently begun to see widespread implementation (Schoenbrunn, 2005). In the last five years it has become commonplace for new projects to incorporate higher tailings densities in their design.…”