Rib/Snook Competency in Mechanised Depillaring of the Conventionally Developed Coal Seams
Authors
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CSIR-CIMFR (Council of Scientific and Industrial Research – Central Institute of Mining and Fuel Research), Barwa Road, Dhanbad, 826 015, Jharkhand ,IN
Arun Kumar Singh -
CSIR-CIMFR (Council of Scientific and Industrial Research – Central Institute of Mining and Fuel Research), Barwa Road, Dhanbad, 826 015, Jharkhand ,INSahendra Ram
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CSIR-CIMFR (Council of Scientific and Industrial Research – Central Institute of Mining and Fuel Research), Barwa Road, Dhanbad, 826 015, Jharkhand ,INRajendra Singh
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CSIR-CIMFR (Council of Scientific and Industrial Research – Central Institute of Mining and Fuel Research), Barwa Road, Dhanbad, 826 015, Jharkhand ,INAshok Kumar
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The stability of a natural support like pillar, fender, rib/snook is fundamental for the success of a bord and pillar mining. In fact, the stability of these supports becomes more important at the time of depillaring than the development. An application of mechanised depillaring, utilising continuous miner (CM), provides faster rate of extraction and, therefore, the roof is not supported during the slicing operation. However, the slicing of an existing square or rectangular type pillar provides irregular shaped rib/snook. Available conventional approaches are difficult to be applied for the design of such a rib/snook. Even the scope of application of a foreign design approach for the rib/snook design is limited, mainly, due to the uniqueness of rock mass and site conditions of Indian coalfields. Considering these facts, a systematic study on numerical models in laboratory is undertaken to understand the required competency of a rib/snook at different stages of a mechanised depillaring operation. Giving a brief background of different important field trials of the mechanised depillaring in Indian coalfields, this paper describes the modelling approach and presents results of these models to show the effectiveness of different sizes of ribs/snooks at different stages of the depillaring. Considering the scope of strata dynamics at the goaf edges, some practical considerations for rib/snook design are also discussed on the basis of different field experiences.
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