著者

伊藤 和男 高階 和郎 杉山 輝芳

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.35, no.190, pp.119-132, 1985-04-30 (Released:2009-06-12)

参考文献数

17

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Recent exploration efforts in the Akenobe Mine has lead the discovery of Chiemon Vein Swarm in the South-western deeper levels of the mine. This vein swarm, consisting of more than forty blind veins, develops mainly below -10 level except No. 5 vein and is formed in the tension fractures of basic lava, basic tuff and slate of the upper Permian Maizuru Group.No. 4 vein, the champion of the swarm, trends NW-SE and dips steeply to the north having strike and dip extension of over 470 m and 200 m, respectively. Most of the other veins, with lesser extension, follow almost similar NW-SE direction, and distribute around this champion vein as branch or parallel veins. Vein fractures are much more developed in basic lava of brittle nature, whereas they are less developed in basic tuff or slate of relatively ductile nature.The occurrences of principal veins show multiple mineralization which are summarized into Cu-Zn, Sn-W and barren quartz from early to later stages.Among these three stages, the distribution of Sn-W stage is limited in No. 4 Vein and Veins of its closest proximity.Current ore reserve calculation from this vein swarm totalled about 1.6 million tons of minable ore, averaging 1.42% of copper, 5.75% of zinc and 0.34% of tin, and still this figure has a very good possibility of remarkable increase as the exploration goes on.In addition, the discovery of this vein swarm proposed us a several new concepts on our exploraiton philosophy which would be extensively applied in the other area of the mine to disclose another blind vein swarms.