• Economic and Environmental Geology
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• v.28 no.3
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• pp.287-303
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• 1995

Tungsten ore deposits in China show clearly their relationship between granitoids and orebodies. All kinds of different tungsten ore deposits, having the largest ore reserves in the world, occur in China. Major tungsten deposits in 1950'years were locally confined in three provinces such as Jiangxi, Hunan and Guangdong. However, the major tungsten ore deposits are replaced by new tungsten deposits such as Sandahozhuang, Xingluokeng, Shizhuan and Daminghsan deposit which may be larger than the previous major deposits. Tungsten ore deposits of China exhibit obviously the granitoid was the ore-bringer to form tungsten ore deposits. The wolframite-bearing quarz veins in China indicate that tungsten mineralization took place by crystallization of wolframite preferentially unless $Ca^{{+}{+}}$ was introduced from outside into the magma-origin-fluid, since it is understood that the scheelite in the Sangdong ore deposit was preferentially precipitated, because of chemical affinity, from the tungsten fluid in which Fe and Ca ions were as sufficient as to form magnetite, wolframite and scheelite. Tungsten deposits in the world are divided into two systems; W-Mo-Sn system and W-Mo system. Most of tungsten deposits in China dated to about 196-116 Ma belong to the W-Mo-Sn system, while late Cretaceous tungsten deposits such as the Sangdong deposit in Korea belongs to the W-Mo system. The genetic order of tin-tungsten-molybdenum mineralization observed in the Moping tungsten mine in China and the Sangdong in Korea may be attributed to volatile pressures in the same magma chamber. It is assumed from ages of tungsten mineralizations that ore elements such as tin, tungsten and molybdenum might be generated periodically by nuclear fission and fusion in a part of the mantle and the element generated was introduced into the magma chamber. The periodical generation of elements had determined association, depletion and enrichment of tin and molybdenum in tungsten mineralization and it results in little association of cassiterite in tungsten deposit of late Cretaceous ages. Different mechanism of emplacement of the ore-bearing magma has brought various genetic types of tungsten deposits as shown in China and the world.

• Economic and Environmental Geology
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• v.11 no.4
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• pp.143-167
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• 1978

The Sangdong tungsten (mostly scheelite) mine is located on the southern limb of a major syncline, the Hambaeg syncline, in a thick sequence of lower Paleozoic sedimentary rocks in the mideastern part of south Korea. Productive scheelite mineralization in Sangdong area is confined to one single formation, the Myobong Slate. Four major ore beds, which have an lateral extension over than 1 km and were not heavily subjected to spatial disturbance, are developed in the Myobong Formation. The original materials of the ore-comprising horizones were probably of either calcareous or silceous sediments. The four ore beds, especially in the case of Main ore bed, display both lateral and vertical zoning. Association quartz-mica-scheelite is predominant in the central, while association hornblende-quartz-diopside-scheelite, diopside-garnet and wollastonite-garnet are developed in this order towards the periphery of the ore beds. Petrologically, two phases of thermometamorphism are recognized. The first phase is represented by the association wollastonite-garnet and diopside-garnet, while the second phase by the association hornblende-quartz-diopside-scheelite and quartz-mica-scheelite. The associations of the second phase do constitute prodctive ore. The high background value of tungsten in the area surrounding the Sangdong mine reveals that the area can be considered a geochemical zone enriched in tungsten. Studies on the trace element patterns were carried out to draw useful criteria for the purpose of future geochemical exploration in the area. The increasing trend of the ratio Rb $({\times}1000)/K_2O$ of the Myobong Slate towards the known mineralization area proved to be indicative for the presence of tungsten mineralization.

• Economic and Environmental Geology
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• v.12 no.4
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• pp.181-195
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• 1979

The Nambu orebodies of the Okbang tungsten mine are hosted in the Precambrian amphibolite and Weonnam formation. These orebodies can be classified into two types; The scheelite-bearing ore vein occurring in the amphibolite (the Nambu 1, 2 adits) and tungsten-bearing quartz vein along the contact between the amphibolite and the Weonnam formation (the Young-ho, -1, -2, -3 levels). The scheelite-bearing ore vein in the amphilbolite is discontinuous, narrow, and highly irregular in geometry, occurring only within the amphibolite with which of the vein is graduational. Based on these feature of the mode of occurrence, the origin of this ore type might be attributed to a potential segregation of tungsten ore fluid in situ from hornblenditic basic magma of the host rock. Tungsten-bearing quartz vein, however, is considered to have deposited along the N30-60E trending fractures as a later hypothermal vein after the hornblendite was emplaced. The principal ore mineral is scheelite with minor amount of wolframite, and the gangue minerals are quartz, and small amounts of fluorite, pyrrhotite, chalcopyrite and calcite. Fluid inclusion study of minerals from the Nambu orebody reveals that the fluids in fluorite of the scheelite-bearning ore vein attained a temperature range of $208{\sim}256^{\circ}C$ and those in quartz from the tungsten-bearing quartz vein a temperature range of $220{\sim}357^{\circ}C$. The real formation temperatures can be somewhat higher than filling temperatures, if pressure correction is made. Chemical analysis of 8 amphibolitc samples on major and some trace elements indicate that the amphibolite is igneous origin. On a Niggli diagram (al-alk)versus c, the analytical values are plotted on an igneous field, and on a Niggli diagram mg versus c they follow a karroo igneous trend line. According to the Ba, Cr, and Ni versus Niggli mg plots suggested by Leake (1964), Okbang amphibolite fall outside a pelitic field and compare favorably with his plots form ortho-amphibolites. Analitical values of $MoO_3$ of 8 samples of scheelite minerals from the Nambu orebody indicate that the tungsten-bearing quartz vein (type n) of Nambu orebody shows a range from 1. 69% to 4.38% which is higher than 0.94%~3.25% $MoO_3$ for the scheelite-bearing ore vein (type I). This fact indicates that the type II was deposited in a lower $fO_2/higher$ $fO_2$ environment and under lower temperature than the type I. Analysis of major components $WO_3$, MnO, and FeO of 6 samples of wolframite from the type II veins revealed that they contain 73.35~76.2% $WO_3$, 7.94~11.63% MnO, and 10.53~14.82% FeO. MnO/FeO ratios of wolframite shows the range of 0.85~1.17 which suggests a slightly higher temperature type of deposits than other major tungsten deposits in the country.

• Economic and Environmental Geology
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• v.18 no.4
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• pp.331-342
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• 1985

The Dongbo tungsten-molybdenum deposits are fissure-filling veins emplaced in granites of late Cretaceous age. Integrated field, mineralogic and fluid inclusion studies were undertaken to illuminate the characters and origin of the ore deposits. Mineral paragenesis is complicated by repeated fracturing, but four distinct depositional stages can be recognized; (I) tungsten-molybdenum minerals-quartz-chlorite stage, (II) iron-oxide and sulfides-quartz stage, (III) iron -oxide-base metal sulfides-sulfosalts-quartz-carbonates stage, (IV) barren rhodochrosite-zeolite stage. Fluid inclusion studies were carried out for stage I quartz and stage III quartz, sphalerite and calcite. Fluid inclusion studies reveals highly systematic trends of homogenization temperature and salinity throughout the mineralization. Ore fluids during stage I were complex, NaCl rich brine and salinity reached values as high as 34.4 weight percent equivalent NaCl, but the later ore fluids were more dilute and reached to 9.7 weight percent equivalent NaCl during stage III. Intermittent boiling of ore fluid during stage I is indicated by the fluid inclusions in stage I quartz. Depositional temperatures and pressures during stage I range from $520^{\circ}C$ to $265^{\circ}C$and from 600 to 400 bars. Homogenization temperatures of the stage III quartz, sphalerite and calcite range from $305^{\circ}C$ to $190^{\circ}C$. Fluid inclusion data from the Dongbo mine are nearly similar to those from other hydrothermal tungsten deposits in the Kyeongsang basin. Depositional temperature and salinity of ore fluids during precipitation of tungsten-molybdenum minerals in Dongbo mine were much higher, but $CO_2$ contents were much lower than those from hydrothermal tungsten-molybdenum deposits of late Cretaceous plutonic association in central parts of Korean peninsula.

• Economic and Environmental Geology
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• v.18 no.1
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• pp.11-22
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• 1985

The Daehwa and Donsan tungsten-molybdenum deposits are composed of numerous fissure-filling veins developed in Precambrian gneiss and Cretaceous granite and quartz porphyry. K-Ar age of biotite in granite and that of muscovite in ore veins are $105{\pm}5\;Ma$ and 88.2~88.6 Ma respectively. Occurrence of ore deposits shows that relevant igneous rock is possibly quartz porphyry rather than above mentioned granite in temporal view point. Vein structure and mineralogy suggest that ore veins were formed by continuous vein filling, not by repeated mineralization. Three distinct depositional stages with decreasing age can be devided on the basis of mineral paragenesis and fluid inclusion studies: Stage I, deposition of oxides and silicates; stage II, deposition of base-metal sulfides and sulfosalts with carbonates; stage III, deposition of barren calcite and fluorite. Tungsten, molybdenum and tin mineralization occurred in stage I.

• Economic and Environmental Geology
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• v.13 no.2
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• pp.117-127
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• 1980

Molybdenum as by-products of Sangdong tungsten mine occurrs in the form of molybdenite in quartz vein. The molybdenum contents of scheelite in Sangdong ore bodies ranges from trace to 8%, therefore the scheelites show variable fluorescence colores under ultra-violet lamp (short wave). The fluorescence color are in order high content of molybdenum, yellow, white and blue. The yellow fluorescing scheelite is dominant in upper ore vein, otherwise the blue fluorescent variety is dominant in lower ore vein. The fluorescence color of scheelite in the main ore vein show zonal distribution becoming progressively more blue outerwards, contrary more yellow innerwards, and even in single scheelite crystal, simillar zonal pattern is observed, too. Molybdenite occurrs as flakes or elongated blades at the margins of the quartz vein only molybdenite bearing quartz veins but also other sulfides mineral bearing quartz veins have mainly blue flourescing scheelites. We suggest that the molybdenum contents of the early stage ore solution are progressively decreased by a subsequent crystallization of the yellow fluorescing scheelites.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.97-102
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• 1986

Concepts on mineral association, mineral paragenesis, and mineralization stage relating to macrostructures of vein filling in ore veins are briefly discussed. As an example of plutonic ore vein, macrostructures of vein filling of plutonic tungsten-tin-copper vein at the Ohtani mine, Kyoto Prefecture, Japan, one of representatives of plutonic tungsten-tin vein related genetically to acidic magmatism of late Cretaceous in the Inner zone of Southwest Japan, are examined. Based on macrostructures of vein filling, three major mineralization stages, are distinguished by major tectonic breaks. Sequence of mineralization, characteristic features of each mineralization stage, and variations of filling temperature and salinity ranges of fluid inclusions in minerals from stage I to stage III are summarized.

• Economic and Environmental Geology
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• v.2 no.1
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• pp.1-12
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• 1969

In the Sangdong Mine area, Taebaegsan series (Pre-Cambrian) and Chosun System (Cambro-ordovician) are widely distributed. The Chosun System consists of Yangdug Series (Jangsan Quartzite and Myobong Slate) and The Great Limestone Series (Pungchon Limestone, Shesong Shale, Hwajeol Formation and Dongjeom Quartzite). The mineralized zone containing the main ore body of the Sangdong Mine was developed in the Myobong Slate formation. The result of the field and microscopic study on the mineral paragenesis and it's wall rock alteration in the tungsten ore deposit shows the following features. The orogenic movements of the Post-Chosun System in the Hambaeg Geosyncline are closely related to the tungsten ore deposition in the area, the ore minerals are composed mainly of scheelite, powelite molybdenite and sulfide minerals, and gangue minerals are hornblende, diopside, garnet, quartz, phlogopite, tremolite, biotite, muscovite, fluorite, etc., main ore body was enriched by scheelite bearing quartz vein filling into interstices of formerly mineralized zones, and the minor faults, faults of N $60^{\circ}-70^{\circ}W$, $45^{\circ}-60^{\circ}NE$ and joints, which were formed at the end of the mineralization and the slate. Country rock of the ore body was altered into the following several zones from the outside to the inside; lowgrade recrystalline aureole, silicified sericite zone, and diopside-hornblende zone. Under the microscopic observation of 195 samples taken from throughout ore body can be classified into 10 different groups by their mineral paragenesis as shown in table 2. The garnet-diopside group is primary skarn and it shows gradational change to the groups of later stage by the successive processes of metasomatism. From the stage of quartz-bearing group, the dissemination of scheelite is seen. The crystallization of scheelite in the bed started with the quartz deposition and continued to the last stage when quartz vein intruded into the main ore body. In the field and the under ground investigation a durable limestone bed in thickeness about 20 meters and their remnants in ore body are observed and under microscope calcite remnants are recognized. Hence it is posturated that the ore material moved up through the faults, shear zones or feather cracks and was assimilated with the interbeded limestone, after that the body was affected by the successive differentiated ore solution by gradational increasing in $SiO_2$, $K_2O$ and $H_2O$. Evidently this ore deposit shows the features resulted from pyrometasomatic processes.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.325-330
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• 2001

Shizhuyuan W-Mo-Bi-Ca $F_2$polymetallic ore is classified to the refractory one due to its complex property, fine dissemination and close association of minerals. Through several years of researches, in line with GY new mineral processing technology developed by Guangzhou Research Institute of Nonferrous Metals, in sulfide flotation circuit, an iso-flotability flowsheet is used to replace original overall bulk flotation flowsheet, and in tungsten flotation circuit, a new chelating type-GY reagent and a special pulp-conditioning system and a new technology of wolframite slime flotation are used to replace the traditional "Caustic Soda Method"$_{［1］}$, the metallurgical performance is greatly improved. Besides, GY New Method has created a favorable condition for comprehensive recovery of fluoride from tungsten flotation tailings. Notable economic benefit has been achieved.d.

• Economic and Environmental Geology
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• v.19 no.1
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• pp.57-66
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• 1986

The ore deposit of the Ohtani mine is one of representatives of plutonic tungsten-tin veins related genetically to acidic magmatism of Late Cretaceous in the Inner zone of Southwest Japan. Based on macrostructures of vein filling, three major mineralization stages are distinguished by major tectonic breaks. The constituents of ore minerals are scheelite, cassiterite, chalcopyrite, pyrrhotite, sphalerite, with small amounts of cubanite, stannite, galena, native bismuth, bismuthinite, arsenopyrite and pyrite. The relationship between the polymorphic variations of pyrrhotite and the kinds of the associated characteristic of ore mineral, in relation with hypogene mineralization, has been demonstrated. Pyrrhotite of stage I is predominantly of the hexagonal phase (Hpo>Mpo). Pyrrhotite of stage II is mainly of the monoclinic phase ($Hpo{\ll}Mpo$). Pyrrhotite of stage III is a single monoclinic phase ($Hpo{\ll}Mpo$). The compositions of the hexagonal pyrrhotite decrease in Fe content ranging from 47.44 atom % Fe in stage I to 46.88 atom % Fe in stage III.