The Experts below are selected from a list of 22917 Experts worldwide ranked by ideXlab platform
David L. Leach - One of the best experts on this subject based on the ideXlab platform.
-
Reactive flow models of the Anarraaq Zn–Pb–Ag deposit, Red Dog district, Alaska
Mineralium Deposita, 2008Co-Authors: Christian Schardt, Grant Garven, Karen D. Kelley, David L. LeachAbstract:The Red Dog Ore deposit district in the Brooks Range of northern Alaska is host to several high-grade, shale-hosted Zn + Pb deposits. Due to the complex history and deformation of these Ore deposits, the geological and hydrological conditions at the time of formation are poorly understood. Using geological observations and fluid inclusion data as constraints, numerical heat and fluid flow simulations of the Anarraaq Ore deposit environment and coupled reactive flow simulations of a section of the Ore Body were conducted to gain mOre insight into the conditions of Ore Body formation. Results suggest that the Ore Body and associated base metal zonation may have formed by the mixing of oxidized, saline, metal-bearing hydrothermal fluids (
Anastassia Y Borisova - One of the best experts on this subject based on the ideXlab platform.
-
multi scale development of a stratiform chromite Ore Body at the base of the dunitic mantle crust transition zone maqsad diapir oman ophiolite the role of repeated melt and fluid influxes
Lithos, 2019Co-Authors: Mathieu Rospabe, Georges Ceuleneer, Nicolas Granier, Shoji Arai, Anastassia Y BorisovaAbstract:Abstract A stratiform chromite Ore Body crops out in the lower part of the dunitic mantle-crust transition zone (DTZ) that developed at the top of a mantle diapir in the Maqsad area in the Oman ophiolite. It is made of layers ranging in thickness from a few mm to a maximum of 3 m, and in modal composition from massive to antinodular and disseminated Ore. The Ore Body is about 50 m thick and its lateral extent does not exceed several hundred meters. The layering dips gently to the southeast, parallel to that of the overlying gabbroic cumulates. The chromite composition is typical of a MORB kindred - moderate XCr (100 × Cr/(Cr + Al) atomic ratio), ranging from 48 to 60, and relatively high TiO2 content, ranging from about 0.3 to 0.5 wt% -, a characteristic shared by most lithologies issued from the igneous activity of the Maqsad diapir. The silicate matrix is essentially made of slightly serpentinized olivine with minor clinopyroxene and rare pargasitic amphibole, orthopyroxene and garnet. This strongly contrasts with the nature of the mineral inclusions mostly made of the assemblage amphibole-orthopyroxene-mica, enclosed in the chromite grains and represented in abundance all along the Ore Body whatever the Ore grade. The inclusions demonstrate the involvement of a silica- and water-rich melt and/or fluid, in addition to MORB, in the early stages of chromite crystallization. The chemical composition of chromite, silicate matrix, together with the one of silicate inclusions display well-defined evolutions vertically along the stratiform chromitite. At the scale of the Ore Body, the compositional trends are independent of the Ore concentration but the major kinks in these trends are well-correlated with levels of magmatic breccias. This shows that abrupt chemical changes can be attributed to sudden melt ± fluids injection events followed mainly by melt-fluid-rock interaction and in a lesser extent by quieter evolution by fractional crystallization. At the thin section scale, second order chemical variations, essentially in the Mg# (100 × Mg/(Mg + Fe2+) atomic ratio) of chromite and Fo of olivine, are clearly attributable to re-equilibration between these two solid phases, possibly in the presence of an interstitial melt/fluid.
Lokeswara R Patnaik - One of the best experts on this subject based on the ideXlab platform.
-
assessment of 222 rn emanation from Ore Body and backfill tailings in low grade underground uranium mine
Environmental Science and Pollution Research, 2014Co-Authors: Devi Prasad Mishra, Patitapaban Sahu, Durga Charan Panigrahi, V N Jha, Lokeswara R PatnaikAbstract:This paper presents a comparative study of 222Rn emanation from the Ore and backfill tailings in an underground uranium mine located at Jaduguda, India. The effects of surface area, porosity, 226Ra and moisture contents on 222Rn emanation rate were examined. The study revealed that the bulk porosity of backfill tailings is mOre than two orders of magnitude than that of the Ore. The geometric mean radon emanation rates from the Ore Body and backfill tailings were found to be 10.01 × 10−3 and 1.03 Bq m−2 s−1, respectively. Significant positive linear correlations between 222Rn emanation rate and the 226Ra content of Ore and tailings were observed. For normalised 226Ra content, the 222Rn emanation rate from tailings was found to be 283 times higher than the Ore due to higher bulk porosity and surface area. The relative radon emanation from the tailings with moisture fraction of 0.14 was found to be 2.4 times higher than the oven-dried tailings. The study suggested that the mill tailings used as a backfill material significantly contributes to radon emanation as compared to the Ore Body itself and the 226Ra content and bulk porosity are the dominant factors for radon emanation into the mine atmosphere.
Christian Schardt - One of the best experts on this subject based on the ideXlab platform.
-
Reactive flow models of the Anarraaq Zn–Pb–Ag deposit, Red Dog district, Alaska
Mineralium Deposita, 2008Co-Authors: Christian Schardt, Grant Garven, Karen D. Kelley, David L. LeachAbstract:The Red Dog Ore deposit district in the Brooks Range of northern Alaska is host to several high-grade, shale-hosted Zn + Pb deposits. Due to the complex history and deformation of these Ore deposits, the geological and hydrological conditions at the time of formation are poorly understood. Using geological observations and fluid inclusion data as constraints, numerical heat and fluid flow simulations of the Anarraaq Ore deposit environment and coupled reactive flow simulations of a section of the Ore Body were conducted to gain mOre insight into the conditions of Ore Body formation. Results suggest that the Ore Body and associated base metal zonation may have formed by the mixing of oxidized, saline, metal-bearing hydrothermal fluids (
Chao Tang - One of the best experts on this subject based on the ideXlab platform.
-
spatial evolution of zn fe pb isotopes of sphalerite within a single Ore Body a case study from the dongshengmiao Ore deposit inner mongolia china
Mineralium Deposita, 2018Co-Authors: Zhaofu Gao, Xiangkun Zhu, Jian Sun, Zhaohua Luo, Chuang Bao, Chao TangAbstract:Analyses of sphalerite minerals from the characteristic brecciated Zn–Pb Ores of the main Ore Body in the giant Dongshengmiao deposit have revealed variations in δ66Zn from 0.17 to 0.40‰ and in δ56Fe from −1.78 to −0.35‰. Further, the investigated pyrrhotite samples have iron that is isotopically similar to that of associated sphalerite minerals. The most distinctive pattern revealed by the zinc and iron isotope data is the lateral trend of increasing δ66Zn and δ56Fe values from southwest to northeast within the main Ore Body. The lead isotopic homogeneity of Ore sulfides from the main Ore Body suggests that there is only one significant source for metal, thus precluding the mixing of multiple metal sources as the key factor controlling spatial variations of zinc and iron isotopes. The most likely control on spatial variations is Rayleigh fractionation during hydrothermal fluid flow, with lighter Zn and Fe isotopes preferentially incorporated into the earliest sulfides to precipitate from fluids. Precipitations of sphalerite and pyrrhotite have played vital roles in the Zn and Fe isotopic variations, respectively, of the Ore-forming system. Accordingly, the larger isotopic variability for Fe than Zn within the same hydrothermal system perhaps resulted from a larger proportion of precipitation for pyrrhotite than for sphalerite. The lateral trend pattern revealed by the zinc and iron isotope data is consistent with the occurrence of a cystic-shaped breccia zone, which is characterized by marked elevation in Cu. The results further confirm that Zn and Fe isotopes can be used as a vectoring tool for mineral prospecting.