Soil and water conservation in mining area based o

Authors: Ailong Wang Liqiang Ma Zhongwei Wang Dongsheng Zhang Ke Li Yao Zhang Xingjun Yi

Publish Date: 2016/04/25

Volume: 75, Issue: 9, Pages: 779-

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Abstract

It has always been a crucial issue in the mining industry that the surface subsidence induced by underground coal mining can lead to the severe deterioration or loss of soil and water resources in mining area Backfilling has become one of the most frequently used mining method to solve this puzzle as it can effectively control the movement of overlying strata and therefore soil and water resources will not be destroyed by mining activities A new type of highwater swelling material HWSM was developed to address the key issues of current backfilling materials used in collieries such as the high cost inadequate strength and low expansion rate Based on the principle that the strength of backfilling body satisfies the requirement a critical ratio of water to solid material a mixture of fly ash which was used as an aggregate lime anhydrite cement and additive ingredients was determined which varied from 081 to 091 Meanwhile the mass ratio of fly ash anhydrite lime cement and additives was determined to be 2460851181 Laboratory tests showed that strength of samples that met the required setting time for practical use could reach 539–552 MPa after 63 days The expansion rate after 3 h varied between 99 and 108  and the bleeding rate ranged from 03 to 033  Industrial application has been conducted in Wangtaipu colliery and results showed that the proposed HWSM had an outstanding mechanical performance with good expansion rates and fluidity These properties indicate that the developed material is suitable for use as a good backfilling material in mining so as to effectively reduce the ground surface subsidence and to conserve the soil and waterThis work was supported by the National Key Basic Research Program of China 973 Program 2015CB251600 the Fundamental Research Funds for the Central Universities 2014YC01 and the Priority Academic Program Development of Jiangsu Higher Education Institutions PAPD

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