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Henan’an, China

Peng F.-H.,Changsha Institute of Mining Research | Li S.-L.,Xiamen University | Cheng J.-Y.,China Molybdenum Co. | Jia B.-S.,China Molybdenum Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering

By using the digital multi-channel microseismic monitoring system, the characteristics of blast stress wave propagation in deep complex and mined-out area and upper fractured rock mass are tested. The wave velocity is acquired by the curve fitting method, which uses the P wave triggering time and propagation distance. The results show that the wave velocities in deep complex and mined-out rock mass and upper coagula rock mass are obviously different. Fitted the curve by using the stress wave amplitude and propagation distance, it is found that the stress wave amplitude decreases in the form of power when the propagation distance increases. By using the signal spectrum analysis and filtering, the attenuation coefficient and frequency are in cubic polynomial relations, and the attenuation of the high-frequency wave is more obvious. The average quality factors in deep complex and mined-out area and upper fractured rock mass, are calculated and they are 4.055 and 2.478, far less than those of the original rock mass, indicating that the mined-out area and fracture have great influence on the stress wave propagation. Source

Xiang J.-F.,Chinese Academy of Geological Sciences | Xiang J.-F.,Nanjing University | Mao J.-W.,Chinese Academy of Geological Sciences | Pei R.-F.,Chinese Academy of Geological Sciences | And 4 more authors.
Geology in China

Nannihu-Sandaozhuang molybdenum deposit is the largest porphyry-skarn type deposit in eastern Qinling region. This paper reports new LA-ICP-MS zircon U-Pb age data of granitoids (including granitic veins) and ICP-MS molybdenite Re-Os isotopic age data of the samples from the mining area. The obtained formation ages of granitoids are 145.2 ± 1.5 - 146.7 ± 1.2Ma, and the model ages of 5 molybdenite samples from stockwork in the Nannihu mining area and 5 molybdenite samples from disseminated skarn in the Sandaozhuang mining area are 143.4 ± 2.0 - 146.5 ± 2.3Ma with isochron age of 146.0 ± 1.1Ma. These new geochronological data show explicitly that the granitoids and ores were formed simultaneously, suggesting their genetic relationship. Furthermore, these new data have confirmed the existence of magma-thermal event at about 158Ma revealed by previous dating work, and also for the first time revealed that the eastern Qinling area once underwent another magma-thermal event at about 175Ma. The published weighted average age data are of distinct deviation from the real intrusive age of the Nannihu magmatic body, which results from 1) nonhomogeneous origin of zircons in magmatic rock and 2) unrepresentative dating of zircon group. Source

Xiang J.-F.,Chinese Academy of Geological Sciences | Pei R.-F.,Chinese Academy of Geological Sciences | Ye H.-S.,Chinese Academy of Geological Sciences | Wang C.-Y.,China Molybdenum Co. | Tian Z.-H.,Luanchuan Longyu Molybdenum Co.
Geology in China

The hydrothermal ore-forming process of the Nannihu-Sandaozhuang Mo (W) deposit can be divided into four stages, i.e., from early to late, (1) skam and hornfels stage, (2) quartz - K-feldspar and retrograde stage, (3) quartz-sulfides stage and (4) quartz-carbonate stage. Based on studies of carbon, hydrogen and oxygen isotopes of different stages, the authors hold that the ore -forming fluid was derived mainly from the magmatic system and subordinately from the carbonate strata with minor organic matter. The atmospheric water probably made very little contribution to the ore -forming process. From early to late stage, the ore -forming process probably experienced immiscibility between melt and volatile-rich hydrothermal fluid, water-rock reaction, and phase separation of CO2 rich gas from ore fluid caused by sudden decompression. Source

Guan W.,Central South University | Zhang G.,Central South University | Xiao L.,Central South University | Zhang Q.,Central South University | And 2 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals

The solvent extraction separation of molybdenum (Mo) and tungsten (W) was carried out from ammonium molybdate solution containing Mo/WO3 of 10%~15% (mass ratio) and WO3 110~150 g·L-1 using a mixture of tri-alkyl phosphine oxide (TRPO) and tributyl phosphate (TBP) as extractant and hydrogen peroxide (H2O2) as complex agent. The molybdenum was selectively stripped from loaded organic phase with ammonium bicarbonate (NH4HCO3) solution. The industrial test was carried out based on the study of extraction-stripping experiment. The relationship among equilibrium pH, extraction stages and the extraction rate of molybdenum and tungsten was defined by kremser equation. The improved measurements including methods of the process of 2-section countercurrent extraction with acid regulation in one of the middle stage and the process of 2-section stripping were proposed. The stability of the new technology was investigated by a long time-running test under the optimized conditions and the economic cost of the technology was analyzed. The result indicated that the concentration of WO3 was 126~151 g·L-1, the concentration of Mo was 0.0019~0.0120 g·L-1, and the Mo/WO3 (mass ratio) was less than 0.9×10-4 in the raffinate under the optimized conditions that the organic phase composition (volume fraction) was 3%TRPO+70%TBP+27% sulfonated kerosene, the flow rate of organic phase was 100 L·h-1, and the concentration of WO3 was 110~150 g·L-1 and the Mo/WO3 (mass ratio) was 10%~15% in the feed solution. The industrial test was successfully and continuously running for about 21 months. The quality of raffinate and stripping liquor were stable, the cycling property of organic phase was good and the running status of the system was stable in the industrial test. The impurity Mo content in the raffinate could fully meet the requirements for producing ammonium paratungstate (APT) of the 0 grade national standards of China. The new technology provided obvious advantages including deep Mo removing, high recovery of W and high added value of Mo product, low cost, clean and environmental friendliness in processing tungstate solution containing high Mo. © 2015, Editorial Office of Chinese Journal of Rare Metals. All right reserved. Source

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