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61.
Makoto Haruna Takahiro Hanamuro Kaoru Uyeda Hirokazu Fujimaki Hiroshi Ohmoto 《Resource Geology》2003,53(2):75-88
Abstract. The petrography, chemical, fluid inclusion and isotope analyses (O, Rb-Sr) were conducted for the shale samples of the Mount McRae Shale collected from the Tom Price, Newman, and Paraburdoo mines in the Hamersley Basin, Western Australia. The Mount McRae Shale at these mines occurs as a footwall unit of the secondary, hematite-rich iron ores derived from the Brockman Iron Formation, one of the largest banded iron formations (BIFs) in the world. Unusually low contents of Na, Ca, and Sr in the shales suggest that these elements were leached away from the shale after deposition. The δ18 O (SMOW) values fall in the range of + 15.0 to +17.9 per mil and show the positive correlation with calculated quartz/sericite ratios of the shale samples. This suggests that the oxygen isotopic compositions of shale samples were homogenized and equilibrated by postdepositional event. The pyrite nodules hosted by shales are often rimmed by thin layers of silica of varying crystallinity. Fluid inclusions in quartz crystals rimming a pyrite nodule show homogenization temperatures ranging from 100 to 240C for 47 inclusions and salinities ranging from 0.4 to 12.3 wt% NaCl equivalent for 18 inclusions. These fluid inclusion data give direct evidence for the hydrothermal activity and are comparable to those of the vein quartz collected from the BIF-derived secondary iron ores (Taylor et al, 2001). The Rb-Sr age for the Mount McRae Shale is 1,952 ± 289 Ma and at least 200 million years younger than the depositional age of the Brockman Iron Formation of ∼ 2.5 Ga in age. All the data obtained in this study are consistent with the suggestion that high temperature hydrothermal fluids were responsible for both the secondary iron ore formation and the alteration of the Mount McRae Shale. 相似文献
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65.
Javier Castro-Larragoitia Utz Kramar Harald Puchelt 《Journal of Geochemical Exploration》1997,58(1):81-91
The Ag---Pb---Zn---Cu---Au mining district of Santa María de La Paz has been extensively exploited for approximately 200 years. Consequences of these activities are several deposits of tailings with high As and heavy metal concentrations, which are completely unstable. The climate is semiarid and as the dumps have no protective cover, material from the dumps is dispersed by strong winds. It is also washed out during seasonally heavy rainfalls. By these processes approximately 100 km2 of surrounding have been contaminated by dump material. The As and heavy metal content of the soils was determined as well as their level in crops (Zea Maize) from agricultural lands in the vicinity of the dumps. In the direction of prevailing winds concentrations up to 1000 ppm Zn, 400 ppm Pb, 16 ppm Cd, 550 ppm Cu and 300 As have been detected in top soils. Using fuzzy cluster analysis the different contamination sources could be identified. Grains of corn from contaminated sites showed no critical concentrations, but leaves which are also used tor fodder, have As-concentrations up to 20 ppm. 相似文献
66.
痕量铁和锰的化学发光检测 总被引:5,自引:1,他引:5
评述了国内外有关铁、锰的化学发光分析进展。从发光体系、操作方式、最佳条件、干扰离子、检测限等各个方面对化学发光法测定铁、锰及其它们与其它组分同时测定中的应用进行分类评述。 相似文献
67.
榴辉岩中铁铝榴石的测定方法研究 总被引:3,自引:1,他引:3
对国内主要矿区铁铝石榴子石纯矿物中铁的价态规律进行了研究。证明其所含Fe均以Fe^2+为主,其质量分数在83-94,并将Fe^2+这特征性成分用于某地榴辉岩中铁铝榴石的间接测定,获得结果与焙烧磁化-磁选法一致且精度好,较磁化法简便,快速。 相似文献
68.
本文剖析了柿竹园钨锡钼铋矿床地勘阶段地质观察粗浅,勘探投入超前,探明储量积压、B+C级储量比例偏大等不合理的勘查工作及其原因。在此基础上,探讨矿区合理的勘探程度,储量比例及由此带来的经济效益。 相似文献
69.
Summary This paper explores an approach to estimation of the viscoelastic parameters of weak floor strata using plate-loading tests. Mathematical equations are derived to describe deformation-time history for the standard Burgers model under three-dimensional stress-strain conditions, which are verified with a finite element model. A number of time-dependent in-mine plate-loading tests were conducted and the values of the viscoelastic parameters were estimated based on the derived equation. It is shown that large discrepancies between the parameter values estimated from the plate-loading tests and those acquired from the in-mine convergence data are the results of neglecting adjacent pillar interaction. Finite element modelling was conducted to investigate the effects of adjacent pillar interactions upon the pillar settlement. Based on the finite element analyses, a correction curve was developed to adjust the viscoelastic parameter values to take into account the interaction between adjacent pillars. With the correction, the parameter values estimated from the plate-loading tests compared favourably with those acquired from the in-mine convergence results. 相似文献
70.
Acid mine drainage (AMD) occurs when sulfide minerals are exposed to an oxidizing environment. Most of the methods for preventing
AMD are either short-term or high cost solutions. Coating with iron phosphate is a new technology for the abatement of AMD.
It involves treating the sulfide with a coating solution composed of H2O2, KH2PO4, and sodium acetate as a buffer agent. The H2O2 oxidizes the sulfide surface and produces Fe3+ so that iron phosphate precipitates as a coating on the sulfide surface. Experiments performed under laboratory conditions
prove that an iron phosphate coating can be established on pyrrhotite surfaces with optimal concentrations of the coating
solution in the range of: 0.2M/0.01M H2O2, 0.2M KH2PO4, and 0.2M sodium acetate NaAc, depending on the experimental scale. Iron phosphate coating may be a long-term solution to
the problem of AMD. The method would be easy to implement; the reagent cost, however, is not low enough, although it is lower
than the conventional treatment with lime.
Received: 30 March 1995 · Accepted: 6 September 1995 相似文献