Overview of Solid Backfilling Technology Based on Coal-Waste Underground Separation in China

Abstract

China is the world’s largest coal producer country. However, large-scale coal mining has led to severe environmental pollution issues such as surface subsidence and gangue piling up. The gangue discharging amount has ranked the first in the world and coal mine enterprises are facing enormous discharging reduction pressure. This paper summarizes the research progress of the solid backfilling mining technology and then illustrates the realistic demands and significance of implementing underground coal-waste separation. It also focuses on the technical principles, systems and key equipment of the common underground coal-waste separation methods, such as the selective crushing method, the dense medium shallow groove method, the vibro-assisted jigging method and full-size water separation method and ray identification method. In addition, the selection steps of underground coal-waste separation method, the design process of large section separation chamber and the design principle of separation and backfilling system are proposed, finally, the mining-separating-backfilling + X for coal mining is put forward. By combining the technology of mining-separating-backfilling with other technologies, such as gob-side entry retaining with non-pillar mining, gas extraction, solid waste treatment, water protection mining, mining under buildings, railways and water bodies, the integrated mining methods, mining-separating-backfilling + setting pillars, gas drainage, treatment, protection and prevention methods are formed. It also introduced the ‘mining-separating-backfilling + gas extraction’ technology’s whole idea, system arrangement, separation equipment and practical engineering application effects based on the specific engineering case of pingmei no. 12 coal mine. The results indicate that the integration of underground coal-waste separation and solid backfilling technology could achieve gangue discharging reduction, underground washing and surface subsidence control. It is effective at realizing green mining.

Determination of the Ultimate Underground Mining Depth considering the Effect of Granular Rock and the Range of Surface Caving

“…e ultimate underground mining depth of the southeast mining area in the Gongchangling Iron Mine was determined at the 110 m level based on numerical simulation and theoretical calculations. To control the expansion of the existing collapse pit and avoid new surface subsidence caused by underground mining, it was necessary to continuously fill the collapse pit with waste rock according to the intensity of underground mining activities [48][49][50].…”

Understanding the Opportunities, Barriers, and Enablers for the Commercialization and Transfer of Technologies for Mine Waste Valorization: A Case Study of Coal Processing Wastes in South Africa

“…Mining and primary ore processing operations produce large volumes of waste. These are normally disposed of in surface waste deposits such as tailings dams and heaps or backfilled into disused workings leading to the risk of environmental pollution [15][16][17][18][19][20][21]. Of particular concern in the case of wastes generated from sulfide-bearing hard rock ores and coal is the formation of acid rock drainage on exposure to air and water [22][23][24].…”

Gob‐Side Entry Retaining Technology with Advanced Empty Hole Butterfly‐Shaped Weakening in Three‐Soft Coal Seam in China

“…As a result, the gob roof is cut off along the edge of the backfill body which can effectively control the deformation and failure of the gob-side entry retaining roof. However, the amount of backfill engineering in this process is huge, requiring a large amount of manpower and material resources which increase the cost of gob-side entry retaining [8][9][10][11].…”