Experience in the Adoption of Room &amp; Pillar Mining Method in the Company OKD, a.s., Czech Republic

Hudeček, Vlastimil; Šancer, Jindřich; Zubíček, Václav; Golasowski, Jiří

doi:10.1134/s1062739117011908

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…They are meant to ensure the stability of the post-excavation area (the field or its part). For new fields of exploitations, in which the room and pillar method will be used, monitoring systems of the rock bolt support are designed to optimize the bolting technological parameters [20]. Room and pillar mining methods are dedicated to horizontally or slightly inclined orebodies.…”

Section: Room and Pillar Methods In Hard Rock Miningmentioning

confidence: 99%

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

et al. 2019

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This paper presents the results of laboratory tensile testing of segmentally-installed glue-in roof bolting. We studied roof bolting of the type Olkusz-16A (Boltech Sp. z o.o., ZGH Bolesław S.A., Bukowno, Poland), additionally equipped with a steel rod coil, which was mounted in steel cylinders filled with a concrete mixture using multi-part resin cartridges with a diameter of 0.024 m and length of 0.045 m. The mounting depths were 0.1 m and 0.2 m, respectively. Our main purpose was to determine the effect of the bolt hole diameter, which assumed the values 0.028 m, 0.032 m, 0.035 m, and 0.037 m, respectively, on the load-bearing capacity of the roof bolting in relation to the mounting depth. We found that the mounting depth of 0.2 m was sufficient for the roof bolting to exhibit its full load and displacement properties for all four diameters of the bolt hole. To determine whether the roof bolting was capable of transferring the load in situ, we presented the results of the predicted load on the roof bolting applied in a room and pillar mining method in an underground mine of zinc and lead ore deposits. Our objective was to determine the influence of the room and pillar mining method geometry on the range of the fault zone of rocks around pits. We designed the deposit excavation model using the Examine3D numerical modeling software, which is based on the boundary element method. We created three-dimensional models for three variants of working space opening widths: featuring two, three, and four rows of rooms. The geometry of rooms and pillars corresponded to the mine conditions; the width, height, and length parameters were all 5 m. We determined the strength, strain, and structural parameters of the rock mass on the basis of laboratory studies of the drill core and rock forms collected from the room longwall. We used the strength factor to specify the maximum range of the fault zone of rocks around pits. In the last stage of research, we compared the load value obtained based on numerical testing with the maximum load obtained in the tensile strength tests of the roof bolting and determined the safety factor of the segmentally-installed roof bolting.

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Section: Room and Pillar Methods In Hard Rock Miningmentioning

confidence: 99%

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

et al. 2019

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“…With the growth of global energy demand, coal, as an important source of energy, has seen an increase in both consumption and production [1,2]. However, due to the increasing scarcity of coal resources, coal mines around the world are facing mining difficulties, and mining has caused varying degrees of environmental damage [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Study on the Mechanism of Surrounding Rock Deformation and Its Control for Roof Cutting Retained Gob-Side Entry in Close-Distance Coal Seams Co-Mining

Yang,

Xu,

Wang

2023

Energies

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Sustainable development in coal mining requires a continuous and efficient method of coal extraction. Research shows that gob-side entries retained through roof cutting retained gob-side (RCGE) are vital for improving mining efficiency, enhancing coal recovery rates, and enabling continuous production. However, the mechanism of surrounding rock deformation during close-distance co-mining of coal seams with this technique is not yet clear. For the Jiaokou coal mine in China, due to an unreasonable stagger distance between upper and lower working faces, the gob-side entries retained at the 9102 tailgate and 10102 headgate experience severe rock pressure, leading to significant prop damage and a sharp reduction in the cross-section of the entry. This greatly hampers the reuse of these entries. To investigate this issue, we established a model to study the stress distribution of surrounding rocks at different stagger distances (20 m, 40 m, 60 m, 80 m, and 120 m) through numerical simulation and optimized the support parameters for the retained entries. Our research found that when the subsidence of the roof in the upper coal seam exceeds 0.74 m but is less than 1.33 m, there is sliding instability in the mining body. When the subsidence exceeds 1.33 m, the mining body will rotate and deform, causing significant mining pressure within the retained entry. A stagger distance of 40 m between the upper and lower working faces can reduce pressure on the face during the mining of the lower coal seam. Extensive field measurements of rock pressure revealed that the damage rate of the single column in the gob-side entries of the upper and lower coal seams does not exceed 5% and 1%, respectively. In summary, this study provides a practical method to reduce damage to entries during the mining process, thereby increasing the continuous production capability of the coal mine. This is critical for the sustainable development of coal mining.

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“…In this method, the overlying rock mass support is ensured by rib pillars within the project-specified period of time. This is achieved through the optimization of the room-and-pillar dimensions (width of rooms and pillars, mining height) in compliance with the effective standards and procedure [5][6][7], or based on specific research [8][9][10][11]. On the other hand, it is quite often the design parameters fail to ensure the target life of the load-bearing elements in the structure of a room-and-pillar mine.…”

Section: Introductionmentioning

confidence: 99%

Operational control of rib pillar stability

Baryah¹,

Evseev²,

Lomakin³

et al. 2020

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In room-and-pillar mineral mining, rib pillars should support overlying rock mass for the specified time limit of production. Therefore, one of the mining safety components is monitoring of the behavior of rib pillars in the course of time. For the conditions of the room-andpillar method of mining, the authors propose a monitoring procedure for rib pillar deformation based on operational measurements of horizontal convergence in stopes. The theoretical and experimental research proves that transverse deformation of rib pillars is an informative parameter suitable for generalized assessment of pillar failure. The obtained ranges of critical transverse deformation rates (50–100 mm/m/yr) in rib pillars can tentatively be used as an indicator of the critical stability of load-bearing structures in room-and-pillar mining. In-situ determination of the integral transverse deformation rates in rib pillars is based on the ratio of the measured horizontal convergence in stopes to the width of pillars. Implementation of the proposed approach in the Upper Kama potash salt mines has proved its applicability to identification of rock mass areas where intense deformation is expected. The comparison of the monitoring data of the transverse deformation rates and their critical values determined makes it possible to predict service life of rib pillars, which is very important in terms of safety of mining operations. This study was supported by the Russian Science Foundation, Grant No. 19-77-30008.

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Experience in the Adoption of Room & Pillar Mining Method in the Company OKD, a.s., Czech Republic

Cited by 4 publications

References 3 publications

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

Study on the Mechanism of Surrounding Rock Deformation and Its Control for Roof Cutting Retained Gob-Side Entry in Close-Distance Coal Seams Co-Mining

Operational control of rib pillar stability

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