Dressing Technology for the Silver Ore in “Iwami” Silver Mine Site, Japan

2002 ◽  
Vol 712 ◽  
Author(s):  
Ryu Murakami ◽  
Jun Takada ◽  
Toshiyuki Torigoe ◽  
Iwao Matsumoto ◽  
Yoshio Toya ◽  
...  
Keyword(s):  
Smelting Process ◽  
Heating Process ◽  
Low Grade ◽  
Archaeological Excavation ◽  
Modern Age ◽  
Foreign Countries ◽  
Silver Mine ◽  
Gold Silver ◽  
Range Of Variation ◽  
Ore Grade

ABSTRACTIn the early modern age Japan was a kingdom rich in metal resources. A lot of gold, silver and copper were produced and exported to foreign countries, nevertheless Japan maintained a national isolation policy. The Iwami silver mine located in Shimane prefecture was the representative silver mine that prospered most. It produced about 10 % of the world's silver output. It is now mostly abandoned and reduced to ruins. Only a famous picture scroll remains to indicate its real activities. Through archaeological excavation started in 1983, it is becoming clear that extensive remains of mining and smelting are preserved. From 1996 scientific investigation of the excavated remains has been conducted. During excavation, and confirmed by scientific research, we recognized that the artifacts deposited during both the mining of the silver ore and the smelting process could be classified into two artifactual types; objects and fragments produced in the dressing process that were not influenced by a heating process and objects influenced by a heating process and produced by smelting and refining. The low grade ore, waste and tailings (remains after gravity concentration) that were scrapped in the dressing process are included in the former type, and the furnace fragments for smelting and refining, tuyeres (blast pipes) and slag and other smelter remains are of the latter type. The waste and tailings scrapped in the dressing process have not previously been studied. This study aimed at systematically investigating the dressing technology and estimating the ore grade through the evaluation of the range of variation in the waste and tailings left as scrap in the dressing process. The analytical results revealed the actual activities practiced at the Iwami silver mine in the dressing process.

II.—Hidden Divergence in Laboratory Strains of Drosophila pseudo-obscura

1944 ◽  
Vol 62 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Rowena Lamy
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Genetic Constitution ◽  
Low Grade ◽  
Testis Size ◽  
Hybrid Female ◽  
Back Cross ◽  
Pure Race ◽  
Range Of Variation

The Race A/Race B hybrid females of D. pseudo-obscura have a high percentage of fertility, comparable with that of females of pure race. The number and viability of their offspring, however, are largely affected by the genetic constitution of the hybrid female as well as by that of the male to which she is mated in the backcross. Hence the performance of any given hybrid is determined in the first instance by the actual strains of the pure races which are used in making the P1 racial cross. Generally speaking the results are of the same order whenever the same strains are used. The progenies of hybrid females of different genetic constitution may differ in three main aspects: (1) The total number of offspring may be comparable with that usually obtained in a pure race cross; it may be reduced to any extent; in certain matings it is consistently at zero. (2) The sex ratio may be completely normal or male-deficient or female-deficient in any degree; completely uni-sexual progenies are sometimes obtained. (The above observations are mainly in agreement with reports of earlier writers; cf. Lancefield, 1929, Dobzhansky, 1936, Mampell, 1941, Sturtevant, 1937.) (3) “Viability characters,” i.e. those affecting general vigour and physical normality, may be of a high or a low grade; some progenies are comparable in this respect with the pure race, the only exception being that they show a much greater range of variation in body-size of both sexes, and in the testis size of males, abnormalities which are common to all back-cross progenies whatever the genetic constitution of the mother or father. Some progenies show in addition deformities of a peculiar type usually affecting the abdomen and occasionally the legs and wings.

Converting Low-Grade Heat Into Power Using a Supercritical Rankine Cycle With Zeotropic Mixture Working Fluid

2010 ◽  
Author(s):  
Huijuan Chen ◽  
D. Yogi Goswami ◽  
Muhammad M. Rahman ◽  
Elias K. Stefanakos
Keyword(s):  
Rankine Cycle ◽  
Phase Region ◽  
Working Fluid ◽  
Condensation Process ◽  
Heating Process ◽  
Low Grade ◽  
Two Phase ◽  
Working Fluids ◽  
Zeotropic Mixture ◽  
Low Grade Heat

A supercritical Rankine cycle using zeotropic mixture working fluids for the conversion of low-grade heat into power is proposed and analyzed in this paper. A supercritical Rankine cycle does not go through two-phase region during the heating process. By adopting zeotropic mixtures as the working fluids, the condensation process happens non-isothermally. Both of the features create a potential in reducing the irreversibility and improving the system efficiency. A comparative study between an organic Rankine cycle and the proposed supercritical Rankine cycle shows that the proposed cycle improves the cycle thermal efficiency, exergy efficiency of the heating and the condensation processes, and the system overall efficiency.

Separating the Anshan-Type Low-Grade Hematite Ore with Process of Gravity-Magnetic Method

2013 ◽  
Vol 303-306 ◽  
pp. 2541-2544 ◽  
Author(s):  
Qing Mei Jia ◽  
Feng Jiu Li ◽  
Ying Li
Keyword(s):  
Magnetic Separation ◽  
High Intensity ◽  
Magnetic Method ◽  
Low Grade ◽  
Hematite Ore ◽  
Ore Grade

According to the nature of the ore which containing hematite and magnetite,under the conditions,for example,ore grade is 24.07%,the first fineness of grinding -200 mesh is 50%，the second fineness of grinding -200 mesh is more than 95%, it is concluded that concentrating circuit consisting of first grind-Feebleness magnetic separation -high intensity magnetic separation，second grind-second-high intensity magnetic separation-shaking tables. Ultimately, A concentrate with a productivity of 19.35%，a grade of 65.89% TFe and the recovery of 52.32%was yielded.

The Optional Study of Refined Feldspar Processing from Kyanite Tailings

2013 ◽  
Vol 712-715 ◽  
pp. 764-768
Author(s):  
Su Juan Yuan ◽  
Zhi Yong Shen ◽  
Xiao Long Lu
Keyword(s):  
Low Grade ◽  
Purification Method ◽  
Ore Grade

The low-grade feldspar from kyanite tailings were studied through the magnetic - Anti-flotation purification method. The ore grade of iron was decraded from 0.98% to 0.09% and e the various factors in the test was studied.

Petrogenesis of amphibole – biotite – calcite – plagioclase alteration and laminated gold – silver quartz veins in four Archean shear zones of the Norseman district, Western Australia

1992 ◽  
Vol 29 (3) ◽  
pp. 388-417 ◽  
Author(s):  
Andreas G. Mueller
Keyword(s):  
Western Australia ◽  
Shear Zones ◽  
Wall Rock ◽  
Alteration Zone ◽  
Mining District ◽  
Low Grade ◽  
Fluid Temperature ◽  
Quartz Veins ◽  
The North ◽  
Gold Silver

The Norseman mining district in the Archean Yilgarn Block, Western Australia, has produced 140 t of gold and about 90 t of silver from 11.24 × 106 t of ore. The district is located within a metamorphic terrane of mafic and minor ultramafic greenstones, intruded by granite cupolas and swarms of porphyry dykes. The orebodies consist of laminated quartz veins, controlled by narrow (0.5–5 m) reverse shear zones that, in general, follow the contacts of metapyroxenite or porphyry dykes. Petrological studies of four shear zones, exposed on the Regent shaft 14 level, Ajax shaft 10 level, and in the stope above the North Royal shaft 5 level, show that the host rocks were metamorphosed to hornblende–plagioclase amphibolites and actinolite–chlorite rocks at temperatures of 500–550 °C prior to mineralization.At the localities studied, intense wall-rock replacement and low-grade (0.5 g/t) gold mineralization are confined to ductile or brittle–ductile shear structures. Alteration is similar in both ultramafic and mafic greenstones, and consists of an inner zone of biotite–quartz–calcite–plagioclase rock with minor actinolitic hornblende and quartz–calcite–actinolite veinlets, and an outer zone, locally developed, of chlorite–calcite–quartz rock. At an estimated pressure of 3 kbar (300 MPa), fluid temperatures during wall-rock alteration are constrained by the hydrothermal mineral assemblages to 480 ± 30 °C in two shear zones on the Regent shaft 14 level, and to 450 ± 20 °C in one shear zone in the North Royal shaft 5 level stope. The mole fraction of CO2 of the fluids is estimated at [Formula: see text], and the sulphur fugacity at 10−6 bar (10−1 kPa) (at 450 °C), based on the assemblage pyrrhotite + pyrite ± arsenopyrite. The development of an outer chloritic alteration zone at North Royal is related to the lower fluid temperature at this locality.High-grade (up to 75 g/t Au, 283 g/t Ag) veins formed within three of the shear zones studied at fluid temperatures of 400 °C and less, by the successive accretion of quartz laminae, separated by films of retrograde chlorite and sericite. The assemblage of ore minerals in the veins differs from that in the altered wall rocks, and includes disseminated galena, Pb–Bi–Ag tellurides, and native gold, which coprecipitated with the quartz. The orebodies at Norseman show affinities to Phanerozoic and Archean gold skarn deposits.

scholarly journals Genesis of langrial iron ore of hazara area, khyber pakhtunkhaw, parkistan

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Naghmah Haider ◽  
Sajjad Khan ◽  
Rehanul Haq Siddiqui ◽  
Shahid Iqbal ◽  
Nazar-Ul -Haq
Keyword(s):  
Iron Ore ◽  
High Energy ◽  
Low Grade ◽  
X Ray Diffraction ◽  
Humid Climate ◽  
X Ray ◽  
High Silica ◽  
Depositional Setting ◽  
Iron Bearing ◽  
Ore Grade

The Iron Ore of Hazara area has been studied at seven locations for detail mineralogical and genesis investigations. Thick bedded iron ore have been observed between Kawagarh Formation and Hangu Formation i.e Cretaceous-Paleocene boundary. At the base of Hangu Formation variable thickness of these lateritic beds spread throughout the Hazara and Kohat-Potwar plateau. This hematite ore exists in the form of unconformity. X-Ray Diffraction technique (XRD), X-ray Fluorescence Spectrometry (XRF), detailed petroghraphic study and Scanning Electron Microscope (SEM) techniques indicated that iron bearing minerals  are hematite,  chamosite and  quartz, albite, clinochlore, illite-montmorillonite, kaolinite, calcite, dolomite and ankerite are the impurities present in these beds. The X-ray Fluorescence (XRF) results show that the total Fe2O3 ranges from 39 to 56% and it has high silica and alumina ratio is less than one. Beneficiation requires for significant increase in ore grade. The petroghraphic study revealed the presence of ooids fragments as nuclei of other ooids with limited clastic supply which indicate high energy shallow marine depositional setting under warm and humid climate. The overall results show that Langrial Iron ore is a low-grade iron ore and can be upgraded up to 62% by applying modern mining techniques to fulfill steel requirements of the country.

scholarly journals Decreasing Metal Ore Grades—Is the Fear of Resource Depletion Justified?

Resources ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 88 ◽  
Author(s):  
Nadine Rötzer ◽  
Mario Schmidt
Keyword(s):  
Mineral Resources ◽  
Resource Depletion ◽  
Low Grade ◽  
Future Supply ◽  
Ore Grades ◽  
Resource Exhaustion ◽  
Increasing Demand ◽  
Technological Improvements ◽  
Over Time ◽  
Ore Grade

Metals are an essential part of modern living. Ensuring the future supply of metals is a key issue in politics, science, and economics because the available amount of mineral resources is limited. To measure the depletion of mineral resources, several indicators are used. Some of them are based on the ore grade, which has been decreasing over time and is thus taken as a sign of resource exhaustion. However, does this assumption hold true? This paper shows that the development of ore grades is mainly the result of the increasing demand and the outstanding technological improvements that made mining of low grade ores profitable. The usage of ore grades as an indicator may, therefore, lead to erroneous conclusions about the safeguard objects. These are not the metals themselves, but the environment that is impacted by their extraction.

Separate the Anshan-Type Low-Grade Hematite Ore With Process of Low-High Intensity Magnetic Separation and Reverse Flotation Method

2013 ◽  
Vol 690-693 ◽  
pp. 3517-3520
Author(s):  
Qing Mei Jia ◽  
Feng Jiu Li ◽  
Ying Li
Keyword(s):  
Magnetic Separation ◽  
High Intensity ◽  
Low Grade ◽  
Reverse Flotation ◽  
Flotation Method ◽  
Hematite Ore ◽  
Nature Ofthe ◽  
Ore Grade

According to the nature ofthe ore which containing hematite and magnetite,under the conditions,forexample,ore grade is 24.07%,the fitst fineness of grinding -200 mesh is 50%，thesecond fineness of grinding -200 mesh ismore than 93%, it is concluded that concentrating circuit consisting of firstgrind-Feebleness magnetic separation -high intensity magnetic separation，secondgrind-second-high intensity magnetic separation- reverse flotation .Ultimately, A concentrate with aproductivity of 18.90%，a grade of 65.21% TFe and the recovery of 51.29% was yielded.

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