Geochemical and mineralogical characterization of tailings of the Dexing copper mine, Jiangxi Province, China

Abstract

The Dexing copper mine is the largest open pit copper mines in Asia, with mining and beneficiation history stretching back more than half a century; consequently it has large amounts of ore tailings. The mineralogy, chemical composition and distribution of elements in the impounded tailings are of great significance to the future utilization and reclamation of the tailings ponds. In total, 1400 tailing samples from 35 drill cores were collected from the 1 tailings pond at the Dexing copper mine. All samples were analyzed to determine their chemical composition. The particle size, XRD, pH and sequential extraction fractions of selected samples were determined. The silt-size fraction dominates the grain-size distribution. Quartz and sericite are the most abundant gangue minerals in the tailings, with medians of 54.3 and 23.7%, respectively. 3D modeling of the tailings pond suggests that the distribution of particle size, minerals and elements is mainly controlled by the gravitational separation during tailings discharge. Silica, Cu, Mo and Ti are enriched in the dam area of the tailings pond, whereas Al 2 O 3 and K 2 O are enriched in the impoundment area. The potential Cu, Ti and sericite reserves in the tailings pond were estimated at 38 149 tons, 142 175 tons and 8.15 million tons, respectively. The tailings are not significantly oxidized and so their environmental risk is low under the present circumstances. Their weak alkalinity and presence of carbonate minerals provide the tailings buffering capacity to weak acids. Sequential extraction data suggest that the mobility of elements in the tailings pond is low; however, about 6040 tons of Cu, 428 tons of Zn, 252 tons of Mo, 145 tons of As and 66 tons of Pb, may be released if the physicochemical conditions change and the tailings become acidic.

Research on the heat dissipation performances of lithium-ion battery pack with liquid cooling system

“…The injected volume was recorded at fixed intervals until the volumetric variation became stable, which was used to calculate the hydraulic conductivity using Darcy's law (kw). Subsequently, the deionized water was replaced by the Cu(SO4)2 solutions with concentration of c0, which were 300mg/L, 500mg/L, 1000mg/L, 2000mg/L, 3000mg/L, and the procedure to determine the hydraulic conductivity was repeated respectively (kc) (referred to research in Pan et al (2017)). The height of the slurry was measured using the vernier calipers at the end of the test, which was used to determine the evolutions in void ratio (e) with the contaminant concentration.…”

A re-assessment of metal pollution in the Dexing mining area in Jiangxi province, China: current status, hydro-geochemical controls, and effectiveness of remediation practices

“…The Dexing copper Mine has an annual production of over 30 million tons of crude ore (Wu et al 2009;Xiao et al 2011). The ore minerals include pyrite, chalcopyrite, molybdenite, shaperite, galena, native gold, and magnetite (Pan et al 2017). The exploitation of the mine has produced hundreds of millions of ore tailings (Wu et al 2009), which were reported to contain several sulfide minerals, including pyrite (3.5%), chalcopyrite, sphalerite, and galena (Tian and Li 2000).…”

“…Although the concentrations of DOC and chloride did not vary significantly among the sampling sites, it appears that the Dawu river (in particular its upper reach) was overall loaded with higher levels of DOC (2.0-5.6 mg/L) and chloride (2.4-4.2 mg/L) than the other two rivers (Table 1). The water from the middle reach of the Dawu river (site DW-2) was weakly alkaline, due to the input of alkaline effluents from a dressing plant and its associated tailing pond, located approximately 10 km upstream from this sampling site (Pan et al 2017).…”