Abstract
Rib spalling disaster at the coal mining faces severely restricted the safe and efficient output of coal resources. In order to solve this problem, based on the analysis of the current status of rib spalling in the three-soft coal seam 1508 Working Face of Heyang Coal Mine, a mechanical model of sliding-type rib spalling was established and the main influencing factors that affect rib spalling are given. The mechanism of grouting technology to prevent and control rib spalling has been theoretically analyzed. A similarity simulation experiment is used to analyze the change law of roof stress under the condition of three-soft coal seam mining. The optimal grouting pressure is determined by a numerical simulation experiment. And, silicate-modified polymer grouting reinforcement materials (SMPGMs) are used in field experiments. After twice grouting operations in the 1508 Working Face, the coal wall was changed from the original soft and extremely easy rib spalling to a straight coal wall and the amount of rib spalling has been reduced by 57.45% and 48.43, respectively. And, the mining height has increased by 0.16 m and 0.23 m, respectively. The experimental results show that the rib spalling disaster of the three-soft coal seam has been effectively controlled.
Highlights
Rib spalling disaster at the coal mining faces severely restricted the safe and efficient output of coal resources
Yin [16] established a cusp catastrophe model and an arc sliding instability model for a fully mechanized caving face with large mining height and proposed a “Solid-liquid Synchronization” fault detection method to control rib spalling with the core of reducing the failure ratio of the support. e compression rod mechanics model of the large mining height rib spalling in the three-soft coal seam was established, the influence of different factors was analyzed, and advanced grouting to strengthen the coal wall with large mining height was proposed [17,18,19]
Kang and Feng [23] summarized the common materials for downhole grouting at present: cement-based, chemical, and cement and chemical composite grouting materials, and pointed out that chemical grouting materials have the characteristics such as fast curing, high strength, and good permeability, which can timely deal with coal accidents such as rib spalling and roof fall quickly and effectively. e polymer grouting reinforcement material for mines was a rapidly developing new application technology in the coal minefield, which can timely and efficiently deal with geological disasters encountered in underground mining and production [24]
Summary
Due to the development of cracks, joints, and beddings in the roof and coal walls, it is easy to rib spalling and roof fall, which brings great hidden dangers to the production of fully mechanized mining face.
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