نتایج جستجو برای: ore deposits
تعداد نتایج: 37204 فیلتر نتایج به سال:
We show evidence that the primary uranium minerals, uraninite and coffinite, from high-grade ore samples (U3O8N0.3%) in the Wuyiyi, Wuyier, and Wuyisan sandstone-hosted roll-front uranium deposits, Xinjiang, northwestern China were biogenically precipitated and psuedomorphically replace fungi and bacteria. Uranium (VI), which was the sole electron acceptor, was likely to have been enzymically r...
Surface geological and geochemical mapping have been key technical contributors to many gold discoveries over the past 25 years. However, in the last ten years there has been a growing emphasis on using geophysical techniques to compliment them in covered terrains. As the search for gold deposits under covered areas expands, there will be increasing emphasis on integrating the geoscientific dis...
In the Dusina area, which is built up of Lower Palaeozoic metasediments, Devonian carbonate complex and Upper Palaeozoic metarhyolites unconformably overlain by Upper Permian sediments, numerous ore occurrences have been investigated: (a) "stratabound" metamorphic hematite deposits in the pre-Devonian metasediments; (b) epigenetic veins and pipes of barite (& calcite) with accessory Hg-tetrahed...
The Eskay Creek gold-silver mine, located in northwest British Columbia, is the highest-grade precious-metal volcanogenic massive sulphide deposit in the world. The mining industry continues to spend more than $2 million each year on exploration for similar deposits in the area. The geologic setting at the minesite is well studied, but large tracts in north-central British Columbia require more...
In recent years the importance of quality has become increasingly apparent due to global competition. According to Banker et al. (1998), quality is the most important strategic issue of top management. It is primarily concerned with consumer’s view of value desired and value received. In general, the term quality addresses two aspects: quality of design and quality of conformance. In the minera...
Abstract— Based on Sm–Nd data, a crustal source of iron-ore fluid was substantiated and the probability age estimation for hydrothermal–metasomatic siderite Bakal Group, Southern Urals, shown first time. The εNd (Т) values (from –13.4 to –17.6) plot in field Riphean shale not Precambrian rift gabbro granite this region. obtained is 970 ± 40 Ma, which consistent with Pb–Pb from major ore phase (...
Mississippi Valley Type (MVT) 1 deposits represent the majority of carbonate-hosted Zn–Pb globally. They typically form in an extensional tectonic setting along passive margins. However, studies on Sichuan–Yunnan–Guizhou Triangle area (SYGT) reveal differences terms essential features typical MVT deposits. We discuss main these deposits, controlled by folds and faults, high-grade ores symbiotic...
The chemistry of pyrite represents a potentially promising new frontier for the research and exploration different types ore deposits [...]
Episodic seafloor spreading, ridge topography, and fault movement at ridges find (more extreme) analogs in the arc and back-arc setting where the volcanogenic massive sulfide (VMS) deposits that we mine today were formed. The factors affecting sulfide accumulation efficiency and the extent to which sulfides are concentrated spatially are the same in both settings, however. The processes occurri...
Ore-reserve estimations of deposits with low mineral concentrations, such as those of copper, gold and tin, are usually made on the assumption that the grades follow a lognormal distribution. Multiple mineralization or reworking of a deposit may have modified the simple distribution expected — producing an overall distribution of grades which can be adequately described by a mixture of lognorma...
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