• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.23-31
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• 2006

Vegetation structure of Samchang, Bongmyeong, Kabjeong, Danbong coal mine and control site was investigated to provide basic information on vegetation rehabilitation of abandoned coal mine lands in Mungyeong. Gyeongbuk Province. The middle and lower layer consisted of 3 and 10 species for Samchang, 2 and 5 species for Bongmyeong, 7 and 11 species for Kabjeong, 9 and 12 species for Danbong coal mine, and 15 and 17 species appeared for control site, respectively. Importance value of Lespedeza cyrtobotrya in lower layer was the highest for in Samchang, and that of Rubus crataegifolius in other coal mine lands wast he highest. Importance value in herbaceous layer was the highest for Arundinella hirta in Samchang, for Corchoropsis tomentosa in Bongmyeong, for Miscanthus sinensis in Kabjeong, for Carex lanceolata and Artemisia princeps var. orientalis in Danbong coal mines, and Calamagrostis arundinacea in control site was the highest, respectively. Species diversity of middle and lower layer for four coal mine lands ranged from 0.201 to 0.666 and 0.612 to 0.895, respectively. Evenness of lower layer ranged from 0.683 to 0.875 for four coal mine lands, and it was 0.990 for control site.

• Journal of Environmental Science International
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• v.26 no.11
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• pp.1267-1274
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• 2017

A Controlled Low-Strength Materials (CLSM) is suitable for mine backfilling because it does not require compaction owing to it high fluidity and can be installed quickly. Therefore, a CLSM utilizing $CO_2$-solidified Circulating Fluidzed Bed Combustion (CFBC) coal ash was developed and it's properties were investigated, since. $CO_2$-solidification of CFBC coal ash can inhibit exudation of heavy metals. The chemical composition and specific surface area of Pulverized coal Combustion fly ash and CFBC fly ash were analyzed. The water ratio, compressive strength and length change ratio of CLSM were confirmed. The water ratios differed with the specific surface area of the CLSM. It was confirmed that the porosity of CLSM affected its compressive strength and length change ratio.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.75-81
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• 2018

At present research on mining backfill materials is being carried out to prevent ground subsidence and breaking by underground cavern of exhausted mines. However, backfill materials can cause secondary environmental issues such as ground pollution. To solve these issues, liner and cover materials are constructed before backfill materials constructed, to inhibit toxic substances form moving to the surroundings. Liner and cover materials, however, should have an accelerating performance after construction and when the accelerating performance is degraded, the work efficiency can be lowered, and the construction cost can be increased, by many rebound content. Therefore, this study develops mining liner and cover materials, and evaluates their accelerating performance and physical properties of liner and cover materials by types and content of accelerating agent. In case of aluminate accelerating agent, it is mixed with more than 5% of liner and cover materials(binder/ratio); thus an accelerating performance satisfying Korean Industrial Standards(KS) occurs, and in case of alkali-free accelerating agent, when it is mixed with more than 7%(binder/ratio), accelerating performance satisfying KS occurs. The more the accelerating agent capacity increases, the more compressive strength decreases. In addition, it is confirmed that compressive strength of aluminate accelerating agent is more degraded than compressive strength of the alkali-free accelerating agent. It is also confirmed that drying shrinkage stability of the alkali-free accelerating agent is better than the drying shrinkage stability of the aluminate accelerating agent.