In this paper, the results of a performance evaluation study carried out in a chromite concentration plant are presented. The plant is a typical of the similar kind of gravity concentrators which are not equipped with basic control and measuring devices. Therefore evaluation of their performance appears to be a difficult task and requires unique methodology. The study commenced with sampling. A week long sampling surveys were repeated twice. First, the data was mass balanced then conventional parameters of equipment efficiency were determined. After detailed evaluation of the performance data, some modifications at the plant operation, i.e. changing screen aperture from 6 trim to 2 mm, limiting capacity for the plant and the possibility of using two rod mills in parallel, were proposed. Their effects on the performance were investigated by using computer simulation techniques. The results show that the performance and capacity could be improved by applying the proposed changes in the flowsheet.