| Budget Amount *help |
¥36,660,000 (Direct Cost: ¥28,200,000、Indirect Cost: ¥8,460,000)
Fiscal Year 2017: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
Fiscal Year 2016: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2015: ¥10,140,000 (Direct Cost: ¥7,800,000、Indirect Cost: ¥2,340,000)
Fiscal Year 2014: ¥14,170,000 (Direct Cost: ¥10,900,000、Indirect Cost: ¥3,270,000)
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| Outline of Final Research Achievements |
We observed around 300 thousand of AE (Acoustic Emission) events by a high-resolution monitoring network close to the active front of a tabular mining stope being advanced northward at 1 km depth in the Cooke 4 Gold Mine in South Africa. The application of the double-difference relative location algorithm resolved seemingly continuous, dense cloud of AEs that extend about 20 m ahead of the stope front into several discrete, steeply dipping tabular clusters a few meters thick and 10-30 m in dip extent, separated by quiet intervals a few meters thick. The tabular clusters had a strike parallel to the stope face and a dip of around 65°, resembling commonly observed large shear fractures along the plane of maximum shear. These observations suggest that discrete tabular clusters of AEs represent macroscopically localized damage structures that formed in the highly stressed intact rock ahead of the stope face and may culminate in dynamic shear events.
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