IMPROVING BLAST EFFICIENCY AND REDUCING BOULDER GENERATION IN LIMESTONE MINES

摘要

Optimisation of blast design is the key factor for the success of open pit mining. Uniform fragmentation is requir9dtotreducing the overall cost of mining. Also the product size demanded by the customer is of utmost importance. Tha aim of this study is to minimise the boulder formation, which is prevalent in limestone mining. Secondary blasting, conducted for breaking boulders, is excessively high leading to increase in mining cost and high air overpressure. At the same time, the excavator preformance too has come down due to handling of boulders, This paper reports the investigations 6ar'ied out in one of the limestone mines located in Central India. Important issues discussed are pattern of drilling, sequence of blasting using V-cut, extended V-cut and priming of hole. The role of hole initiation using EXEL/RAYDET and air decking are also highlighted for future application. A detalied cost analysis of both the existing and modified practice was done to establish an optimum blast design.