During the past decade, several enhanced gravity concentrators have evolved to commercial scale as a result of the need to achieve efficient gravity-based separations for the treatment of ultrafine particles. The initial interest in enhanced gravity separators (EGS) was for the recovery of fine gold, which represents a low product flow rate application whereby the … Read more
The purpose of the present investigation was to study the possible role of Fe3+ ions in the flotation of sulfide minerals, specifically on activated sphalerite and chalcopyrite. Experimental Sample: Specimen-grade Chalcopyrite & sphalerite was obtained from the Ward’s Natural Science Est., Inc. It contains 0.035% Fe, 0.012% Cu and <0.001% Pb by weight, and has … Read more
Commercial pressure leaching autoclaves have been in operation since mid 1950s. Historical production data suggest that these early autoclaves were originally designed with excess capacity (Berezowsky, Collins, Kerfoot, and Torres, 1991). Process development initially consisted of tests in batch autoclaves. While in some cases this stage had been followed by continuous pilot plant tests in … Read more
Flotation Performance in Function of Collector Type & Dosage at Fixed Grind Size: The drop-off in measured plant recovery due to excessive collector dosage has been described. In the above publications, a rate model was used for describing experimental cumulative recovery versus time data of the form: r = R { 1 – [1/(Kt)][1- exp(-Kt)]} where … Read more
Silicosis, a debilitating and potentially deadly lung disease, develops through inhalation of excessive levels of respirable crystalline silica dust. In underground coal mines, continuous miner operators have historically been at a high risk of overexposure to silica, with over 25% of compliance dust samples exceeding the permissible exposure limit. Flooded-bed scrubbers are fan-powered dust collectors … Read more
The limitations that ore reserve estimators have faced in the past while trying to estimate recoverable reserves stem from different aspects. There are several factors that curtail the effectiveness of the “traditional” geostatistical models: A variogram model is required to derive the VCF; it is well-known that the VCF value itself is greatly influenced by … Read more
Carboxylate can interact with metal cations in four different modes, namely ionic, unidentate, bidentate, and bridging as depicted in Figure 9. The ionic type of interactions are usually observed in the alkali metal salts of carboxylic acids. In this case, the carboxylate ion has a symmetrical structure and the two oxygen atoms in the carboxylate … Read more
Ag-Pb-Zn and Ag-Au Peruvian sulfide ores were used for the pilot plant tests. For these tests, a stream of mineral slurry was directly obtained from the industrial grinding circuit to assure similar particle size distribution in the feed to both the Density Separator and the hydrocyclones. Table 1 presents the chemical analyses and specific gravity … Read more
The Paques technology for the biological treatment of sulfate and metal containing waste waters or process waters, marketed under the name THIOPAQ, consists of different biological processes complemented with liquid/solid and gas separation steps. The produced hydrogen sulfide can be used in various metallurgical processes. The most important biological reaction is the reduction of sulfuric … Read more
Nitrate is normally present in waters associated with mining as a result of blasting activities using ammonium nitrate or dynamite. It may also be present in groundwater and surface water in agricultural areas from fertilizer use. Nitrate is also normally present in municipal and industrial waste streams after the aerobic degradation of ammonia. The concentration … Read more