Mandal, Prabhat Kumar and Singh, Arun Kumar and Buragohain, J. and Singh, Rajendra (2002) A novel method of mining for underground winning of contiguous sections of a coal seam under fragile parting. Journal of Mines, Metals & Fuels, 50 (1&2). pp. 25-33. ISSN 0022-2755

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Extraction of clean coal from thick and contiguous seams/sections is a major problem for mining engineers. Coal mining industry of the country needs a suitable technology for extraction of the same in the presence of weak and laminated parting in between. An idea of underpinning was conceived to facilitate safe and optimal exploitation of coal from contiguous seams/sections, which involved conventional system of development of the sections of seam along floor with superimposed pillars. Underpinning consolidated parting stability through reinforcement and provided additional thickness to the critical parting as the roof coal band of the thick bottom section is stitched together with the parting. The technology was experimented at Zero seam of Chirimiri colliery underneath Bartunga hill of SECL Here, the Zero seam of over 12m thickness was found in two sections, 3.0m top and 6.0 m bottom with the 3.5m thick parting between the two sections. The 3.0 m thick and laminated parting, comprised alternate layers of shale, carbonaceous shale, coal and mudstone, found incompetent for safe and clean working of both the sections. Both top and bottom sections were developed along floor using roof bolts. The weak parting and the roof coal band of the bottom section was reinforced simultaneously by underpinning to strengthen the parting as well as to facilitate extraction of bottom section roof coal. Pillars were extracted by splitting and slicing. The slices of bottom section were supported by conventional props, roof bolting in addition to the reinforced roof coal band and parting by underpinning. The roof coal above bottom section was blasted down on retreat leaving fragile parting undisturbed, supported by underpinned cable bolts. Composition of the multi-layered parting by underpinning did not allow separation and collapse of clay/shale layers resulting clean coal blasted from the roof. The method proved its technological feasibility and success through experimental trial, which is detailed in this paper.

Item Type: Article
Subjects: Thick Seam Mining
Depositing User: Dr. Satyendra Kumar Singh
Date Deposited: 30 Nov 2011 07:10
Last Modified: 30 Nov 2011 07:10

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