Stress-state monitoring of coal pillars during room and pillar extraction

Waclawik, Petr; Ptáček, Jiří; Koníček, Petr; Kukutsch, Radovan; Nemcik, Jan

doi:10.1016/j.jsm.2016.06.002

Cited by 30 publications

(12 citation statements)

References 5 publications

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“…In addition, due to the influences of mining disturbance caused by the lower seam extraction, and mining activities in overlying strata and lateral roof strata tend, the stopping roadways and coal pillars would seriously deform, resulting in a series of adverse consequences. This can lead to strong ground pressure behavior of working faces, rib‐spalling of coal walls, and even rockbursts …”

Section: Introductionmentioning

confidence: 99%

Experimental study on the overburden movement and stress evolution in multi‐seam mining with residual pillars

Tian

Yang

Sun

et al. 2019

Energy Science & Engineering

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When faced with multi‐seam mining, some coal pillars are left to support the overlying strata when mining the lower seam, where stress concentration usually occurs. When the working face in the lower seam advances to the area influenced by these coal pillars, high ground pressure behavior occurs. Furthermore, the instability of coal pillars under the participation of the roof may induce rock burst, which threaten the safe production of coal mine. To study the roof strata movement and coal pillar instability in multi‐seam mining, a coal mine in Datong was taken as an example. Firstly, the bursting liability of coal and rock stratum was tested. The test results show that the 7#, 8#, and 11# coal seams in the mining area all have strong bursting liability. And the roof was dominated by siltstone and firestone, which also have strong bursting liability. Then, based on the geological conditions of the coal mine, we investigated roof movement and instability of the coal pillar during multi‐seam mining through physical simulation. The simulation results indicate that multi‐seam mining aggravates the roof damage, which leads to the increase in the fracture range of overlying strata, and that the failure height increases from 46 to 121 m. In addition, the detailed distribution of stress on residual coal pillars and its influence on the lower working face were studied through numerical simulation. The results show that, when the working face 8707 of the 8# coal seam advances to a horizontal distance of 20 m from the coal pillar, it enters the influence zone. As the working face advances beneath the coal pillar, the stress reached to 24 MPa. Moreover, when the working face passes by the coal pillar, the coal pillar is cutoff, thus affecting the working face.

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Section: Introductionmentioning

confidence: 99%

Experimental study on the overburden movement and stress evolution in multi‐seam mining with residual pillars

Tian

Yang

Sun

et al. 2019

Energy Science & Engineering

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“…Bieniawski analyzed the dimension effect of coal pillar strength, and proposed that coal‐rock masses have a critical dimension in which the coal pillar strength will not become decreased with increases in dimension when the coal pillar dimensions are larger than the critical dimension. To determine the pillar stability, Waclawik et al measured the vertical stress in two adjacent coal pillars which were diamond shaped and located within a row of pillars that formed the panel. The results of the stress‐state and pillar displacement monitoring allowed the pillar loading and yielding characteristics to be described.…”

Section: Introductionmentioning

confidence: 99%

“…At present, the short‐wall mining techniques still use the coal pillar method for roof control. Therefore, the main focus has been on the self‐strength and long‐term stability of coal pillars . However, there have been few studies conducted regarding the use of short‐wall continuous mining and full‐caving methods.…”

Section: Introductionmentioning

confidence: 99%

A study of the dynamic movement rule of overlying strata combinations using a short‐wall continuous mining and full‐caving method

Wen

Cheng

Chen

et al. 2019

Energy Science & Engineering

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At present in China, short-wall working face coal-mining methods are among the main methods used for the high-efficiency recoveries of boundary coal pillars and residual pillars. In traditional short-wall mining methods, overlying roofs are supported by coal pillars. However, issues such as the excessive number of coal pillars, low coal recovery efficiency, large areas of hanging roof arches, etc, have been encountered. In view of the aforementioned issues of the current short-wall mining technology, this study took the short-wall mining of the Yujialiang Mine in the Shendong mining area as the project background. The study then proposed a judgment method for the key stratum on the working face of the mine using a short-wall continuous mining and full-caving method. The proposed method was based on the theory of elastic plates and was verified using the theoretical analysis results of similar material simulation experiments. FLAC 3D software was adopted to analyze the stress and displacement evolution processes of the overlying rock strata during the advancement of the working face using a short-wall continuous mining and full-caving method. The results showed that the short-wall continuous mining and full-caving method not only had the ability to improve the recovery rate, but was also able to realize the effective control of the roof areas, thereby avoiding any large areas of hanging arches. The short-wall continuous mining and full-caving method is potentially of important significance for the improvement of coal recovery rates, as well as for the safe and highly efficient mining of boundary coal pillars and residual pillars in mines under special conditions. K E Y W O R D Scaving span, composite key stratum, numerical simulation, short-wall continuous mining and full caving, similar material simulation experiment | 2985 WEN Et al.

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“…At present, when designing underground operations, calculations for operational losses, and consequently, the deposit utilization factor [2], are separately performed. Also, calculations of rock bolt support loads [3][4][5][6] are separately carried out. In underground mining systems, the relationship between room and pillar geometry is known as a deposit utilization factor.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Room and Pillar Method Geometry on the Deposit Utilization Rate and Rock Bolt Load

Skrzypkowski

2019

Energies

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In this article, a model of ore deposit in form of a lense carried out in the MineScape program, is presented. The lense had a thickness of 30 m, length along the strike 200 m, and the depth buried was for 80 m to 110 m below the surface. In the first layer, counting from the lowest level, a room and pillar method with variable geometry was designed. The width and length dimensions for rooms and pillars were: 4 m, 5 m and 6 m, respectively. For the selected part of the deposit, three variants of the system with variable geometry of rooms and pillars were designed, for which the deposit utilization coefficient was determined. The next stage of the research was to determine the influence of the geometry of the pillars and rooms on the range of the rock destruction zone around room excavations. For this purpose, numerical calculations using the three-dimensional Examine 3D program, based on the boundary element method, were made. The results of numerical tests were used to calculate the load of the rock bolt support, which is currently used in the zinc and lead underground mine "Olkusz-Pomorzany" in Poland. Currently in the mine, the bolt spacing is 1 m × 1 m, and the technology for fixing the bolt rod is based on resin cartridges that completely fill the bolt hole. In order to spread the spacing of the rock bolt support and to apply segmental fixing of the bolt rod, in the laboratory tests, rock bolt supports with increased strength were tested. Based on the results obtained, it was found that the rock bolt can be installed segmentally, using a cement grout, and its spacing can be increased to 2 m.

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Stress-state monitoring of coal pillars during room and pillar extraction

Cited by 30 publications

References 5 publications

Experimental study on the overburden movement and stress evolution in multi‐seam mining with residual pillars

Experimental study on the overburden movement and stress evolution in multi‐seam mining with residual pillars

A study of the dynamic movement rule of overlying strata combinations using a short‐wall continuous mining and full‐caving method

The Influence of Room and Pillar Method Geometry on the Deposit Utilization Rate and Rock Bolt Load

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