Prasad, Mohan (1995) Post-Pillar Behaviour at Deep Levels in a Copper Mine. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstract , 32 (6). pp. 585-593. ISSN 0148-9062

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Mosaboni mine is one of the copper mines in the Singhbhum Thrust Belt in Bihar, India. The post-pillar stoping method has been employed to exploit a shallow dipping wider orebody at deeper levels (950m) in the mine. In this method, slender pillars are left at regular intervals in stopes to support the immediate stope back. The main rock mechanics aspect of the method is that post-pillars (PPs) should yield under the fill and be in a post -failure condition, most of the superincumbent load being transferred to the abutments. Numerical simulation of post-pillars (4 x 4m square) with clear room of 9 x 13m between them is simulated using FLAC software. The model analysis showed that the PPs were in a post-failure state since their formation. However, if they are provided with confinement by applying support to them and are prevented from unraveling, they will be able to support the stope back. It is further observed in the numerical modelling that once the yielding portion of the pillar was buried under the fill, it becomes stabilized. In actual mining practice there are PPs larger in size and closely spaced. Fractures appear on their sides followed by spalling of fractured rock. The lateral deformation in one of the pillars was monitored to study its stability. It was found that the lateral deformations induced by stresses were controlled by foliation and joint planes. A 2 x 2m core of the pillar was stable and movement was restricted to a 1.5m zone from the periphery of the pillar.

Item Type: Article
Subjects: Bord and Pillar Mining
Depositing User: Dr. Satyendra Kumar Singh
Date Deposited: 22 Jan 2012 10:21
Last Modified: 22 Jan 2012 10:21

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