Design of Stable Parallelepiped Coal Pillars Considering Geotechnical Uncertainties
IR@CIMFR: CSIR-Central Institute of Mining and Fuel Research, Dhanbad
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| Title |
Design of Stable Parallelepiped Coal Pillars Considering Geotechnical Uncertainties
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| Creator |
Kumar, Ranjan
Mandal, Prabhat Kumar Ghosh, Nilabjendu Das, Arka Jyoti Banerjee, Gautam |
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| Subject |
Longwall Mining
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| Description |
The stability of underground parallelepiped coal pillars formed during trunk road development in inclined coal seams is very important for safe access to the mine workings. These protective coal pillars developed around the trunk roads have the longest life span in coal mines. Although these pillars are designed with high safety factors, their failures continue to occur especially in inclined coal mines. The acute corners of parallelepiped coal pillars are highly stressed and prone to failure. These failures may be attributed to the deterministic safety factor which does not consider field geotechnical uncertainties in their design parameters. This research work identified the geotechnical uncertainties in pillar designs and incorporated them in designing stable pillars in inclined coal seams. A probabilistic approach based on limit state function has been proposed for designing stable parallelepiped coal pillars and validated in an inclined coal mine. In this study, the working stresses of the inclined coal pillars are varied for evaluating their influence on pillar reliability using the three cases of the limit state functions namely, empirical, numerical average, and numerical maximum. The pillar reliabilities were estimated by Monte Carlo Simulation. The results indicate that the empirical and numerical average cases yielded stable pillars, whereas the numerical maximum case provided an unstable design. The correlation between safety factor and reliability has been established which can predict the reliability for a given safety factor of pillars with a similar range of design inputs. Further, the threshold values of pillar sizes, acute corner angles, and seam gradients for the reliable pillar design have been determined by sensitivity analysis. These findings can help in designing stable parallelopiped pillars, especially in inclined coal seams to reduce pillar failures and enhance mine safety.
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| Publisher |
Springer
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| Date |
2023-09
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| Type |
Article
PeerReviewed |
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| Identifier |
Kumar, Ranjan and Mandal, Prabhat Kumar and Ghosh, Nilabjendu and Das, Arka Jyoti and Banerjee, Gautam (2023) Design of Stable Parallelepiped Coal Pillars Considering Geotechnical Uncertainties. Rock Mechanics and Rock Engineering , 56 (9). pp. 6591-6602. ISSN 0723-2632
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| Relation |
http://cimfr.csircentral.net/2652/
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