The ore enrichment process has evolved greatly over time. In the beginning it began in the stopes with manual selection of the ore, reaching the plant with an enrichment of approximately 6 times in relation to its grade when stopped. It was difficult to do adequate manual selection in the stopes, therefore a coarser choice was done in the stopes, and a finer choice made in the Barroca Grande Plant in ore already washed, screened and with good lighting conditions. The pre-concentration continued by jigging and the pre-concentrate then went to the Cabeço do Pião plant.