著者

高 秀君 大久保 誠介 福井 勝則 金田 博彰

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.122, no.1, pp.26-34, 2006 (Released:2007-02-24)

参考文献数

20

被引用文献数

1 1

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For flood prevention, power generation and conveyance, the world's largest Three Gorges Dam was begun to construct in 1993. However, the problem of landslide around the Three Gorges reservoir has not been solved completely so far. Although a lot of geological investigations have been carried out in the field, the role of rock mechanical characteristics in the failure of rock slope has not been cleared thoroughly.In order to study the geological setting and the mechanical characteristic of the landslide area around the Three Gorges reservoir, field investigation and laboratory work including microscope observation, X-ray powder diffraction analysis and uniaxial compressive tests have been carried out. Rock specimens such as two muddy sandstones, a red mudstone, a limestone and a sandstone were collected and examined.The main mineral composition of examined rock specimens except for limestone is quartz. Under the air-dried condition, sandstone is the strongest and weathered muddy sandstone is the weakest. It is interesting to note that calcium contents (carbonate observed) in unweathered muddy sandstone are significantly decreased in weathered one. The decrease in strength for the weathered rock may arise from the dissolution of calcium. For all sample rocks, uniaxial compressive strength shows remarkable decrease under the water-saturated condition. It may be attributed to high content of clay minerals.Complete stress-strain curves were obtained. For all sample rocks, stress increased almost linearly with strain up to the peak strength and then dropped rapidly indicating brittle feature. Weakening under water-saturated condition and high degree of brittleness indicate that very careful and sophisticated measure is necessary to prevent landslide in the area.

著者

正路 徹也 小林 祥一 孟 憲国 金田 博彰

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.112, no.10, pp.683-687, 1996-09-25 (Released:2011-01-27)

参考文献数

2

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The availability of GPS (Global Positioning System) has been examined in three areas. The first is a fixed point on the roof of a building of the University of Tokyo. The second area is around the Hishikari gold mine, southwestern Japan. The area was selected because topographic maps (1/25, 000) are published. The topography consists of gentle hills. The third area is Yunnan Province, southwestern China, where foreigners are prohibited to use topographic maps. The surveyed area is mostly mountainous. Measured values at the fixed point are scattered within 100m from the true position. The average point is located 30m south from the true position. In the Hishikari area, each GPS value is compared with the coordinates given by a topographic map. The deviation between the GPS value and the coordinates is within 300m. The reason why the deviation is larger than the error at the fixed point is that the coordinates given by a map includes error. In Yunnan, the accuracy was checked by the reproducibility. At many sites, satellites were not found because of steep slopes and high trees. A relatively wide space was located, however, within 300m from each site. When 4 satellites were found in wide areas, values were scattered in a circle with a diameter of 200m. When 4 satellites were found in narrow areas, the diameter was 500m. When only 3 satellites were found, the diameter was 1, 000m. These values are larger than the error of the pacing (less than 10 m for 100m distance). The result suggests that the GPS can provide location data with the accuracy enough to geoscience discussions in regional scales.

著者

正路 徹也 佐々木 望 金田 博彰 武内 寿久禰

出版者

一般社団法人 資源・素材学会

雑誌

日本鉱業会誌 (ISSN:03694194)

巻号頁・発行日

vol.96, no.1103, pp.1-6, 1980-01-25 (Released:2011-07-13)

参考文献数

19

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The high grade of cobalt characterizes the deposit of the Shimokawa copper mine which is one of the most famous bedded cupriferous pyrite deposits of Japan. Unfortunately, however, the cobalt has not been recovered, because the concentration of cobalt is difficult. In order to show the distribution of cobalt in the ore, the microscopic observation and the electron microprobe analysis have been carried out. The main ore minerals are pyrite, chalcopyrite, monoclinic pyrrhotite, sphalerite, cobalt pentlandite, and cobaltian mackinawite in the descending order of abundance. Among them, pyrite is the most important carrier of cobalt, and cobalt pentlandite is subordinate. The cobalt of the copper concentrate depends upon the small mingled grains (less than 20μm) of cobalt pentlandite which is closely associated with chalcopyrite. On the other hand, the pyrite concentrate owes its cobalt amount to cobalt-rich pyrite. On the basis of the texture of ore and the crystal form of pyrite, the mode of occurrence of pyrite is divided into seven types as shown in Figs. 1 (a)-(g). The R-type pyrite having a rounded form is the richest in cobalt among them, and contains a average cobalt concentration of 0.8 wt.%.These natures of ore suggest that the cobalt of the coppem concentmate may be recovered as a by-pmoduct of the copper smelting, and that the cobalt of the pyrite concentrate may be recovered as a cobalt concentrate consisting of R-type pyrite.

著者

金田 博彰 正路 徹也 高木 秀雄 小林 祥一 加藤 泰浩

出版者

東京大学

雑誌

基盤研究(B)

巻号頁・発行日

2000

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中国の地質区は、ほぼ東西の境界線で北より、シベリアプレート(Siberia Plate)、タリム〜北中国プレート(Tarim-North China Plate)、中央オロジェニックベルト(Central Orogenic Belt)、南中国プレート(South China Plate)、チベット〜雲南プレート(Tibet-Yunnan Plate)、インドプレート(Indian Plate)に分けることができる。現在、日本を始め世界の先進国においては新たな資源の発見・開発はほとんど無いといってよい。特に、日本は資源品国の代表である。これに対して、開発途上国の代表である中国は、今でも全土から数多くの新たな鉱物鉱床の発見がみられる。中国において、1993年以降発見、開発が進められてきた鉱床および鉱化地帯は70箇所におよぶ。これらの鉱床のほとんどは、本研究での調査地域の中国中部〜南部域に分布する。すなわち、上述の中央オロジェニックベルト、南中国プレート、チベット〜雲南プレートに分布する。各鉱床が産出する主要鉱種は、銅、鉛、亜鉛、金、銀、錫、タングステンなどである。また、数は少ないもののマンガン、鉄、ウランなどもある。鉱床によっては、希土類元素、ニッケル、モリブデン、金・銀、アンチモンなどの副産物を随伴する。銅鉱床規模を、Super large (Cu総埋蔵量:100万t以上)、Large(100万t〜50万t)、Medium(50万t〜5万t)、Small(5万t以下)に4区分すると、Super LargeとLarge規模のほとんどの鉱床は本研究の調査地域に分布する。予測される銅(Cu)埋蔵量は、Super Large=100万t以上、Large=281万t以上、Medium=55万t以上、Small=1.2万t以上と見積もられる。また、鉛・亜鉛鉱床は6地域と銅に比べ少なく、全てSouth China Plateに分布する。6鉱床中5つがLarge規模(Pb+Zn=100万t〜500万t)である。予測される資源量は、166万t以上である。金銀鉱床は、ここ10年間で30箇所発見・開発されている。ほとんどの鉱床は、South China PlateとCentral Orogenic Beltから発見されている。これらから予測される埋蔵量は、金=305t以上、銀=6300t以上と見積もられる。錫・タングステンは中国を代表する資源である。これらはSouth China Plateより新たに4鉱床発見された。予想埋蔵は、90万tと見積もられる。以上、近年中国で新たに発見・開発されている鉱物鉱床は、そのほとんどが本研究調査・研究地域に分布する。