Study On The Non-Working Residual Coal Recovery Scheme Of The No.Ⅱ Open-Pit Mine In Thar Coalfield

In the process of the construction and development of near-horizontal composite coal seam open-pit coal mine,the problem of side-gang pressurized coal is widespread,but the research generally only focuses on the problem of surface or lower coal seam remining,and lacks a unified middle and lower coal seam recovery scheme.Taking the problem of backlog of residual coal under the non-working help of the No.II open-pit mine in Thar Coalfield as the starting point,this paper formulates the scheme of coordinated recovery of the lower and middle and high coal seams on the basis of ensuring the stability of the slope.Aiming at the problem of non-working residual coal recovery,the influencing factors of non-working help slope stability are first summarized,and the slope stability is analyzed and calculated to determine whether the non-working help residual coal can be remined in the whole disclosure way.Based on the needs of slope stability,the recovery scheme of the lower coal seam is formulated for cross-mining and internal mining and the middle coal seam is segmented,and the recovery method is optimized based on economic judgment.Combined with the determined collaborative mining plan,the earned value method is used to coordinate and control the construction progress and cost of the mining plan.The residual coal recovery scheme was applied to the actual site of the No.II open-pit mine in Thar Coalfield,and the lower coal seam was recovered by cross-mining internal drainage.The medium and high coal seams were recovered by using the coal column method between the recovery stages;Expand the internal discharge space while recycling more residual coal.Based on the schedule benchmark plan,the earned value method is used to coordinate and control the cost and progress of the mining plan,and combined with the actual construction progress trend on site,the indicators of the mining plan on the 50 th day of implementation are statistically analyzed,and the total construction period and construction cost are predicted.In the end,the entire residual coal recovery plan recovered 4,492,940 tons of additional coal,and at the same time expanded the capacity of the inner discharge space by 2,337,000 m~3.After the progress and cost coordination and control,the construction period of the original on-site construction plan was 28 days earlier,and the cost balance was 4.4925 million yuan.There are 43 figures,10 tables and 50 references in this paper.