نتایج جستجو برای: ore deposits

تعداد نتایج: 37204  

2017
Theodore J. Bornhorst Ryan Mathur

The Keweenaw Peninsula native copper district of Michigan, USA is the largest concentration of native copper in the world. The copper isotopic composition of native copper was measured from stratabound and vein deposits, hosted by multiple rift-filling basalt-dominated stratigraphic horizons over 110 km of strike length. The δ65Cu of the native copper has an overall mean of +0.28‰ and a range o...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
R B Gordon M Bertram T E Graedel

The relative proportions of metal residing in ore in the lithosphere, in use in products providing services, and in waste deposits measure our progress from exclusive use of virgin ore toward full dependence on sustained use of recycled metal. In the U.S. at present, the copper contents of these three repositories are roughly equivalent, but metal in service continues to increase. Providing tod...

1999
Ioannis Konstantinou Kapageridis Bryan Denby G. Hunter

Ore grade estimation is a key aspect in the evaluation of a mineral deposit. In this paper an alternative approach to currently applied methods of ore grade estimation is presented. This alternative approach involves a modular neural network system integrated in a state of the art 3D resource modelling package. The need for a new method of ore grade estimation comes from the difficulties in app...

2010
Michael D. West Jonathan D.A. Clarke

The future exploration of Mars is likely to utilize resources that can be extracted in situ. An overview of the geology of Mars has been presented and several mechanisms that could result in the formation of ore deposits have been identified. These include deposits caused by hydrothermal fluids resulting from volcanic activity, large igneous province formation and impact craters. Surface enrich...

Journal: :Science 2009
Andrey Bekker Mark E Barley Marco L Fiorentini Olivier J Rouxel Douglas Rumble Stephen W Beresford

Some of Earth's largest iron-nickel (Fe-Ni) sulfide ore deposits formed during the Archean and early Proterozoic. Establishing the origin of the metals and sulfur in these deposits is critical for understanding their genesis. Here, we present multiple sulfur isotope data implying that the sulfur in Archean komatiite-hosted Fe-Ni sulfide deposits was previously processed through the atmosphere a...

Journal: :journal of tethys 0

pb-zn deposits in the kurdistan region, northern iraq, have occurred mainly as a stratabound and open-space filling ore bodies. they are hosted by dolostone and dolomitic-limestone of platform carbonates. the ore deposits at the studied dure and lefan areas are respectively hosted by kurra chine (upper triassic) and bekhme (upper cretaceous) formations. pyrite, sphalerite and galena are the maj...

Journal: :زمین شناسی اقتصادی 0
رضوان مهوری رضا شمسی پور دهکردی هاشم باقری موسی نقره ئیان محمد علی مکی زاده

kalchoye copper-gold deposit is located about 110 kilometers east of esfahan province and within the eocene volcano sedimentary rocks. sandy tuff and andesite lava are important members of this complex.the form of mineralization in area is vein and veinlet and quartz as the main gangue phase. the main ore minerals are chalcopyrite, chalcocite, galena and weathered minerals such as goethite, iro...

2015
Frank J. Calixto

Attenuation images are obtained from 6287 t-star spectral measurements of P-wave microseismic events in a mine setting. The resulting three-dimensional quality factor (Q) model reveals that most of the study region is characterized by low Q values or high attenuation (Q<25), probably caused by cavities and fractures due to mining activities. Q values between 25 and 50 show a high spatial correl...

Journal: :Journal of the Mineralogical Society of Japan 1963

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