Placer gold sampling—the overall measurement error using gravity concentration on particle size ranges during sample treatment

摘要: Author Summary: Placer deposits are generally characterized by low grade of free gold. This is the case in French Guiana where main placer river bed. Most have already been exploited very small mining companies using sluices. If this technology efficient for coarse gold, it releases fine gold tailings. During last years, studies performed on various sites and recoveries estimated between 40 60% depending size distribution particles quality sluice configuration. Many recent or ancient tailings available with a non-negligible quantity remaining offering retreatment opportunities. They found form sand heaps shape an alluvial fan originating at discharge. Due to resulting large heterogeneity necessary take many samples strategically deployed locations. These be enough representative local material. As mainly liberated type lot, traditional sample treatment successive reductions sub-samplings not can expensive. Another approach sieving gravity concentration per particle range preferred presented here. After presentation sampling measurement protocol used, paper focuses estimation overall error. Various tailing cases which decision depends level confidence obtained estimate recoverable