plocculant evaluations in a counter current decanter thickening process: laboratory and field results

摘要

Vater and land management is an essential part of any mining operation; it must not only be considered in planning a mine, but throughout its existence and eventually, its closure. This is not only due to tighter governmental restrictions and reduction in resources, but also due to the changes in ore quality, and the waste generated. A decrease in ore quality would result in an increase in the water required for processing, and in the ore required to yield the same level of mined goods, thus increasing the volume of tailings needing to be managed. It was stated by the United States Geological Survey (USGS) in 2005 that nearly four billion gallons of water were used for mining related activities globally, and this number has only increased with the escalating demand on mined goods as well as the decreased ore grade. Therefore, a tailings management system will require further optimisation to cope with such challenges. A counter current decanter (CCD) process associated with a copper/gold mine in Indonesia currently operates under a traditional flocculant system. In efforts to reduce the consumption of fresh water, this site is working to evaluate alternative water sources, such as that from acid rock drainage and seawater. The work included in this study focuses on the evaluation of the effect of various process modifications, such as water quality and ore particle size, on the efficiency of the incumbent flocculant system as well as several alternate flocculant chemistries in efforts to recommend an optimal flocculant system to assist in achieving these desired process modifications. These alternative chemistries have demonstrated a substantial improvement over the incumbent system in the settling rates and sludge volumes without negatively affecting the overflow clarity in evaluations of both seawater and acid rock drainage, as well as, with various levels of particle size due to the degree of grinding.