Meng Q.,Peking University |
Meng Q.,University of Stockholm |
Zhang J.,Chinese Research Academy of Environmental Sciences |
Zhang J.,Beijing Normal University |
And 3 more authors.
Chemistry and Ecology | Year: 2016
This study investigates the partitioning of metals in surface sediments from the Dan River drainage basin, the source of drinking water for the South to North Water Transfer Project, China, to determine their bioavailability and associated levels of risk. Sediment samples were collected from 99 sites along the Dan River, and the concentration of each element fraction was determined using sequential extraction and inductively coupled plasma-mass spectrometry. The residual fraction was the major phase for most metals sampled. Among the non-residual fractions, greater proportions of Zn, Mn and Cd were transported in in the available phase, whereas Ba, Sb, Pb and As were mainly found in the reducible phase. The oxidisable phase was important for the transport of Ni, Co, Cr and Cu in sediments. This analysis of sediments from the Dan River basin indicates a very high risk of pollution from Cd, Co, Mn, Sb and Zn. Combined with the sediments with extremely high concentrations, the Dan, Laoguan and Yinhua rivers, which have been affected by ore-mining activities, pose a very high risk to the surrounding areas and should be the subject of future studies. © 2016 Taylor & Francis
Guo L.,Chinese Institute of Crustal Dynamics |
Guo L.,Peking University |
Liu Y.,Peking University |
Liu Y.,Wuhan University |
And 5 more authors.
Lithos | Year: 2013
The Gangdese belt, Tibet, records the opening and closure of the Neo-Tethyan ocean and the resultant collision between the Indian and Eurasian plates. Mesozoic magmatic rocks generated through subduction of the Tethyan oceanic slab constitute the main component of the Gangdese belt, and play a crucial role in understanding the formation and evolution of the Neo-Tethyan tectonic realm. U-Pb and Lu-Hf isotopic data for tonalite and granodiorite from the Xietongmen-Nymo segment of the Gangdese belt indicate a significant pulse of Jurassic magmatism from 184Ma to 168Ma. The magmatic rocks belong to metaluminous medium-K calc-alkaline series, characterized by regular variation in major element compositions with SiO2 of 61.35%-73.59%, low to moderate MgO (0.31%-2.59%) with Mg# of 37-45. These magmatic rocks are also characterized by LREE enrichment with concave upward trend in MREE on the chondrite-normalized REE patterns, and also LILE enrichment and depletion in Nb, Ta and Ti in the primitive mantle normalized spidergrams. These rocks have high zircon εHf(t) values of +10.94 to +15.91 and young two-stage depleted mantle model ages (TDM2) of 192Ma to 670Ma. The low MgO contents and relatively depleted Hf isotope compositions suggest that the granitoid rocks were derived from the partial melting of the juvenile basaltic lower crust with minor mantle materials injected. In combination with the published data, it is suggested that northward subduction of the Neo-Tethyan slab beneath the Lhasa terrane began by the Late-Triassic, which formed a major belt of arc-related magmatism. © 2013 Elsevier B.V.
Zhang Y.,China University of Geosciences |
Gu X.,China University of Geosciences |
Bai X.,No.8 Gold Geological Party of CAPF |
Liu R.,China University of Geosciences |
And 3 more authors.
Earth Science Frontiers | Year: 2013
The Zhesang gold deposit hosted in the Upper Permian sedimentary clastic rocks of the Wujiaping Formation is a typical Carlin-type gold deposit in Southeast Yunnan metallogenic belt. Bed-like and lenticular ore bodies are restricted to fractured zone. The studies of sulfur isotopes indicate that the δ34S values of hydrothermal sulfides (pyrite and arsenopyrite) range from 8.3‰ to 11.3‰, which is generally similar to that of diagenetic pyrite and Permian marine sulfates, suggesting the sulfur was mainly derived from strata. Sulfur dynamic fractionation was mainly controlled by organic thermochemical sulfate reduction (TSR). The research of lead isotope shows that 206Pb/204Pb values have a relatively wide variation range, while 207Pb/204Pb and 208Pb/204Pb values have little change. The calculated model ages of lead have a great varying range (-62 Ma to 389 Ma), and even contain negative age, showing that there was an addition of radiogenic lead to common lead. The lead of ore and ore-bearing strata was mainly provided by upper crust, with a little mixed source of magma. In brief, both sulfur and lead isotopic data show an inheritance between ore and ore-bearing strata, that is, ore-forming materials mainly came from strata.
Jia Y.,CAS Institute of Process Engineering |
Sun H.,CAS Institute of Process Engineering |
Chen D.,Wanbao Mining Ltd |
Gao H.,Wanbao Mining Ltd |
Ruan R.,CAS Institute of Process Engineering
Hydrometallurgy | Year: 2016
Microbial communities and activities in multi-lift bioleaching heap of copper sulfide ore were investigated at Monywa copper mine, Myanmar. The high-throughput sequencing method revealed a microbial community dominated by archaeal Ferroplasma (about 70%), rather than more commonly reported genera of Acidithiobacillus and Leptospirillum (together about 25% in Monywa heap). Multi-lift stacking operation without heap aeration resulted in low oxygen concentrations in the heaps (leachate oxygen concentration of 0.35 mg L− 1 to 0.68 mg L− 1). Therefore, low oxygen concentrations, high organic matter concentrations and moderate temperature in the heaps favored the growth of versatile Ferroplasma which can both undergo autotrophic and heterotrophic growth. Total cell number in the irrigation solution and leachate was in the range of 4.86–8.80 × 106 mL− 1, and the detected microbes in ore residues and leaching solutions were mainly those with iron-oxidizing ability. Their iron-oxidizing rate showed highest at the temperature of 35 °C, while in heaps may be limited by the low oxygen supply. Monywa bioleaching system with the above mentioned microbial community and activity formed a leaching solution of low redox potential, resulting in appropriate pyrite oxidation during chalcocite dissolution, thus helped maintain relatively stable acid and iron concentration in the cycling leaching solution. This study explained the formation of the microbial community and activity in Monywa heap leaching, linking to its heap physical and chemical conditions, and suggested that the role of Ferroplasma in bioleaching system may have been overlooked previously, especially in oxygen-limited bioleaching heaps. © 2016 Elsevier B.V.
Liu C.,University of Science and Technology Beijing |
Han B.,University of Science and Technology Beijing |
Sun W.,University of Science and Technology Beijing |
Wu J.,University of Science and Technology Beijing |
And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2015
Cemented backfilling technology has been increasingly used in the exploitation of mineral resources under the low temperature condition, but it has also brought about a series of difficult issues, such as the problem of poor strength of backfilling materials, the collapse and the failing. The effects of the curing temperature, the cement content and the slurry concentration on the strength of backfilling materials were thus studied experimentally to tackle the problems faced in a gold mine at cold region. The rational proportions of mixed material contents and the curing temperature of paste of cement-rock debris mixture were determined to meet the requirement of gravitational transportation. The experimental results revealed that the cemented rock debris was better than the iron ore tailings as the backfilling material and its slurry concentration reached to 75%. The low temperature was found to hinder the hydration. The higher the curing temperature was, the higher the uniaxial compressive strength (UCS). The increasing of curing temperature improved the strength of backfilling material. The curing temperature influenced more on the early strength but little on the later strength of backfilling material. The heated water for rock debris mixing and cementation was therefore proposed and applied successfully in an industrial experiment. ©, 2015, Academia Sinica. All right reserved.
Gao Y.-D.,General Research Institute for Nonferrous Metals, China |
Gao Y.-D.,State Key Laboratory of Rare Metals Separation and Comprehensive Utilization |
Zhong C.-G.,General Research Institute for Nonferrous Metals, China |
Zhong C.-G.,Wanbao Mining Ltd |
And 6 more authors.
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2016
The activation mechanism of Pb2+ in flotation of wolframite with benzohydroxamic acid as collector was studied through flotation test, adsorptive capacity, IR spectroscopy, XPS study and flotation chemistry calculation. The results show that Pb2+ can increase the floatability of wolframite and the optimum pH region is 6-10, the floatation recovery rate reaches maximum when pH=9; the adsorption test shows Pb2+ can promote the adsorption of benzohydroxamic acid onto the surface of wolframite, and the adsorption isotherm obeys Freundlich equation quite well; tthe result of XPS study shows the main activity of species is Mn2+, and the floatation chemistry reveals the majority of Mn2+ exists as surface manganese hydroxide; two oxygen atoms from hydroxamate anion chelate manganese hydroxide on the surface of wolframite and form five-chain complex. © 2016, Science Press. All right reserved.