Study on Fully-Mechanized Caving Technique Parameters in Contiguous Seams and Lower Thick Seam by Simultaneous Mining

In order to improve the top coal recovery rate of contiguous seams and lower thick seam by simultaneous mining, based on analyzing geological conditio n of Quandian Coal Mine, the paper used PFC simulation software to analyse the parameters of top coal caving, and determined the drawing interval was 0.6 m, and u sed uplink coal caving technique. The coal caving effect was measured, and observations results showed that average caving time of every support was 84 s, the size 0 f the broken top coal was under 10 cm, the size of the broken immediate roof was under 30 cm. After top coal caving, 10. 3% of the caving mouth didnDt find gangue, a nd 86. 9% of the caving mouth controlled the proportion of gangue under 60%, average recovery rate of the working face was 80. 41%, and the highest mining rate was 84.3%.