A Novel Longwall Mining Layout Approach for Extraction of Deep Coal Deposits

Abstract

As more easily mined deposits are depleted, the reserves are becoming more limited and less favorable. Deposits of coal or trona that are being longwall mined are deep and are getting deeper. Coal bursts and bumps frequently occur within development entries in longwall mining of deep mines due to high stresses. This paper presents a novel patented longwall mining layout "Longwall Mining with Split-level Gate roads (LMSG)" that has the potential to mitigate several problems related to deep mining (Patent No. ZL98100544.6). LMSG locates gate roads on either end of a longwall panel at different vertical heights within a coal seam or in a geologically split seam, so that the two adjacent panels can be partially offset horizontally. It is novel in that it incorporates unit operations of different mining methods into the system. By employing multiple slice longwall mining method locally at the face ends, and adjacent panels overlapping end to end, pillar-less longwall mining can be achieved to mine deep deposits. A conventional rectangular gate road pillar is therefore transformed into a small triangular pillar and the gate road of the subsequent panel can be located along or under the gob of the previously mined panel where the stresses are lower. Several mines in China and Russia are currently using the technology with reduced incidence of ground control problems. Through theoretical analysis, and physical and numerical modeling approaches, it is demonstrated that LMSG significantly improves stress environment for development entries, with associated reduction in coal bursts and ground control problems.

Monitoring the Geometry of Powered Roof Supports—Determination of Measurement Accuracy

“…Based on the results of the performed model testing as well as the analyses and in situ observation for the analyzed case in coal seam, the authors presented the following conclusions: the results of the numerical calculations confirmed that the longwall panel stability depends not just on the powered support capacity, but also on the correct geometrical parameters of the powered support. The relationship between rocks and powered supports was also presented in [14][15][16].…”

The sustainable development of coal mines by new cutting roof technology

“…The finite-element software was applied to simulate the bolt and anchor cable support. The beam element could not only conveniently define the anchorage lengths of the bolt and anchor cable, the cohesive strength and stiffness of the resin roll, but also could bear the tensile and shear effects of surrounding rocks [31]. Therefore, the beam element was used in the simulation.…”

Numerical analysis of inter-panel pillars in the bump prone conditionals of the Alardinskaya mine

“…The efficiency of underground mining of coal seams depends on the correct choice of the applied mining technology. The main method of coal mining at present is the development by longwalls [1][2][3], the work of which is to conduct mine workings along the contour of large rectangular blocks of coal (longwall panels). The overlying rocks lose their support during coal extraction, and some of these rocks fall down.…”