Recovery of Placer Gold by Knelson Centrifuge and Gemeni Table (Case Study: Placer Gold Damghan ́s Kohe Zar Mine)

Today, the use of Knelson centrifuge and Gemeni table in placer gold processing plants has replaced traditional gravity separator such as Gig, Spiral and Shaking tables. The 90 to 95 percent recovery rate in plants using these new technologies has led to the increasing use of these machines in placer gold processing plants. In this paper increasing of recovery of placer gold using Gemeni table and Knelson centrifuge has studied. The samples were taken from Damghan´s kohe zar mine. Grade of samples were 0.52 ppm. Studied effective parameters on operation of Knelson were: rate of dry feed (400-520 gr/min), speed of bowl (60-100% of total power) and pressure of water (1-3 psi). The tests designed according to Tagouchi tests plane. ­­Finally at the optimum operational condition the obtained recovery and grade of concentrate were values 93.92% and 19.8 ppm, respectively. The notable point in this project is, we selected final concentrates of Kelson as feed of Gemeni table tests. Studied effective parameters on operation of Gemeni table were such as: Frequency of Gemeni table, flow rate of wash water and rate of feed. Recovery and grade values of concentrate obtained: 87.9% and 60 ppm, respectively.