• Tunnel and Underground Space
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• v.23 no.3
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• pp.180-191
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• 2013

The purpose of this research was to find an optimal quarrying for marble by analyzing the applicability and the work efficiency of a chain saw machine newly introduced in the underground Baekwoon mine. From the test results of the physical properties of Baekwoon marble, which affects the efficiency of rock cutting, it was found to have similar physical characteristics as the ones which are now being produced in the other areas in Korea. And especially it shows isotropic property, which can be thought to be advantageous as a dimensional stone. To check the long-term quality of the marble as a stone material, several tests such as corrosion resistance test and abrasion test were carried out. It was found to be vulnerable to acid rain with decrease of weight and seismic wave velocity after applying artificial rain at pH 5.6 for 50 times. The percentage of wear from abrasion test was 22.67%. The working time and cutting speed of the chain saw machine were recorded and analyzed during the test-run at the quarry. The overall work cycle was assorted into 9 unit operations and the operating time per each unit was drawn. The operating times for the two cutting patterns, which could be possibly applicable to the work site, were compared. The results indicated that the pattern B, that the cutting sequence was set to minimize the movement of the machine, showed 6% less working hours than the pattern A, which first cuts the outer boundary. With cutting pattern analysis, the ore body in the Baekwoon mine was 3 dimensionally modeled and a quarrying plan considering the existing conditions of the marble was suggested.

• Journal of Forest and Environmental Science
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• v.24 no.1
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• pp.47-51
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• 2008

The first pruning works of planted trees on forest area carry out when tree height reached at 6 meters. And the second works carry out when it grow to 12~13 meters of tree height. Pruning works are necessary for producing straight log without knar by tool or machine. Generally, the mechanized pruning works Self-propelled pruning machine, chain pruning saw and other tools are used in mechanized pruning works. However, manual pruning saw which is usually using pruning tool was for this study. To investigate the pruning works efficiency, Pinus densiflora, Pinus koraiensis and Pinus rigida which were distributed in Kangwon-Do was surveyed. Height of surveyed the trees were 10~16 meters and its pruning works range were 6.2~6.7 meters of tree height. As results, pruning works efficiency of Pinus densiflora, Pinus koraiensis and Pinus rigida were 3.14 min/tree, 5.06 min/tree and 4.44 min/tree, respectively. Also, possible pruning works of man-day for Pinus densiflora, Pinus koraiensis and Pinus rigida was 104, 64, and 81 trees, respectively.