Optimum Support Design for Openings Considering Intact Rockmass in Production Level of Maddhapara, Granite Mine, Maddhapara, Dinajpur, Bangladesh

Abstract

Maddhapara Granite mine is the only Hardrock underground mine, which is contributing to infrastructure development of Bangladesh. It was established in 1995 by the North Korean contractor (NAMNAM).Over the past few years it was observed that in some of the vital area of the pit bottom, appears to be vulnerable, where needs to be taken special consideration to make sure the safe working environment for the miners and equipment machinery as well. The authors of this research have taken an attempt to identify and overcome such problem by a research program. In this research, our outcome has been established that the, optimum support have to be determined by using Rock Support Interaction Analysis for rock mass in production level. During design stage, it was considered that the total rock mass is intact (based on initial geological survey data), means there are no wedges along the opening. However a little amount of geological abnormality anticipated in the production level during construction phase. Due respect to that, our research recommended that, there has to be a little amount of support is needed for any kinds of openings in first category of rock, in second category it has to be considered by shotcreting of different thickness of lining in roof and the sidewall. In third category of rock, support system has to be considered by rock bolting and latter shotcrete the roof and side wall. Finally 2.3, 4.6 and 10.73 m openings in third category of rock there needs to be 0.0095m 0.015m and 0.026m fiber reinforced shotcrete and 3m bolt length and blot spacing with 1.5, 1, 0.95m respectively in roof and inside wall 0.006m, 0.015 and 0.045m shotcrete lining have to be considered for safe mining work.