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[en] Pitchblende veins are sparsely distributed in an 8 x 1 km zone of northeast-trending, steeply dipping Aphebian sedimentary rocks deposited on Archean granitic basement and affected by complex faulting. They occur in brecciated dolomite of the Union Island Group on the east shore of Union Island, and along fractures subsidiary to a nearly vertical, northeast-trending fault between phyllites of this group and arkosic quartzite of the younger Sosan Group, which is exposed for a distance of 4 km on Opener Island to the east. The veins are close to the unconformity between the host rocks and the younger, gently dipping clastic redbeds of the Late Aphebian Et-Then Group, which most probably covered the mineralized zone at one time. A supergene origin for the veins is proposed on the basis of geological setting, mineralogy, presence of Ag, Se and V, isotopic dates on pitchblende, and lack of evidence for alternative magmatic or metamorphic hydrothermal sources
[en] Sediment and panned heavy mineral survey were conducted in the province of Pangasinan in Luzon Island for a cumulative period of 1 1/2 months in 1983. A total of 40 stream sediments and 125 panned heavy mineral concentrates were obtained along active rivers and streams draining into the Lingayen Gulf and Luzon Sea. The minus 80 mesh sediment fractions and non-magnetic portions of the heavy minerals were analyzed for total uranium using delayed neutron activation analysis techniques. Results indicated that uranium values ranged from 0.1 ppm to 1.4 ppm and 0.1 ppm to 23.2 ppm for the stream sediments and heavy minerals respectively. The uranium values obtained in the stream sediments were considered to be within the range of the average uranium concentrations in northwestern Luzon. However, uranium values in the heavy minerals, in general, were higher than the values obtained in northwestern Luzon. One uranium anomally area was found in San Carlos. (author)
[en] The uranium potential of the Tertiary rocks of late Eocene and younger ages in the Texas coastal plain are evaluated. This evaluation of uranium potential in east Texas is based entirely on the literature. There are three uranium areas in south Texas named for the counties of their principal occurrence: Karnes, Live Oak, and Duval. The potential resources of the various parts of the south Texas coastal plain are discussed from the standpoint of the factors affecting deposition of epigenetic uranium deposits. Potential resource figures are 100,000 tons of probable resources, 128,000 tons of possible resources, and 31,000 tons of speculative resources
[en] Present article is devoted to perspectives of development of coal deposits in Tajikistan. The description some of them, including Fan-Yagnob Coal Deposit, Shurab Coal Deposit, Ziddi Coal Deposit is given.
[en] Present article is devoted to achievements, problems of implementation of new technologies and issues of investments in coal development in Tajikistan. The perspective of coal industry on 2013-2020 years, which includes: the integrated development of coal deposits, private financing or partnership of government and private capital, modernization of technical and production base of coal producers was proposed.
[en] The energy requirements of the future will be met increasingly from nuclear sources at least for the next few decades. This means the discovery of substantial new reserves and resources of uranium which, in the past, have been found mainly on the basis of geological knowledge. New concepts to enhance those built up over a century are urgently required to guide future exploration. These can best be established by interchange between fundamental and applied geologists and by the build-up reliable quantitative data relating to uranium distribution. An international meeting was held at the Royal Society in December 1977, contributions to which have been produced in this book. It is hoped that the initiative taken will stimulate further dialogue on a world-wide basis
[en] Conditions for the criticality of natural reactors are investigated from a general point of view; a parametric study is presented, which expresses the possibility of chain reactions as functions of five parameters: the age of the deposit, the ore's uranium content, the volume of high-grade ore, the neutron capture of the vein of ore and the amount of water associated with the uranium. It is demonstrated that although criticality could theoretically be attained for ages that are not in excess of 1000 to 1200 MA, conditions would have to be exceptionally favorable for it since the deposits are clearly much younger than those at Oklo. The study offers a much better appreciation of the probability for discovery of other natural fissionable reactors
[en] Most of the main genetic types of uranium deposits occur in Canada. They contain a significant portion of the world's uranium resources. However, there are other economically important types of uranium deposits that to date have not been discovered in this country. As there is no fundamental reason why they could not be present, geologists working in Canada need to be aware of their characteristics so that they are not overlooked in future exploration programs. (author)
[en] The world's largest uranium deposits, and some with the highest uranium grades, are of the unconformity type. Included in this category are the Nabarlek, Ranger and Jabiluka deposits of the Northern Territory, Australia, and the Cluff Lake and Key Lake deposits of northern Saskatchewan, Canada. The uranium occurs mainly as pitchblende or uraninite in structures such as breccia zones, faults and ruptured folds near the unconformable contact of lower Proterozoic metasediments and overlying fluvial sandstone. Many of the ore-bearing rocks are between 1300 m.y. and 1800 m.y. old. Some deposits contain metals other than uranium, such as gold and nickel. (author)