Optimization of Fragmentation in benches for Dragline deployed in large opencast coal mines- A case study of Indian mine

摘要

The deployment of Dragline machines in opencast coal projects involves huge capital expenditure aswell as operating costs. The mine operators always endeavor to ensure smooth excavation of material bythe Dragline machines while meeting the major objectives of safety, minimal disturbance toenvironment and optimal operating costs. Optimization of fragmentation through well designed blasts isfundamental in meeting part of the objectives is good fragmentation of rock or mineral proposed to belifted by the Dragline machine. If the overburden lying over mineral is not properly fragmented, it mayresult in formation of ‘Toe' the removal of which is the most arduous task in opencast coal mines. Themine operators always endeavor to achieve best possible results in blasting to ensure smooth operationof the high cost Dragline Machine. However, despite continuous efforts by the blasting engineersinvolved in bench blasting for the machine, the formation of ‘Toe' is an ever nagging problem faced inlarge opencast coal projects eventually reducing the overall operational efficiency of mining.The case study is from ‘Nigahi' project one of the biggest Indian opencast coal mine located at Singraulicoalfields at Madhaya Pradesh state in India. Thorough technical investigations conducted by theauthors of this article revealed presence of certain controllable parameters in the design of drilling andblasting for the overburden material to be lifted by the Dragline machine. The technical services fromthe blasting engineers of one of the major suppliers of bulk explosives in India were utilized inidentifying the root cause, with the primary objective of eliminating the undesirable effects insubsequent blasts and ensure ‘Toe free' fragmentation and increased productivity of the Draglinemachines.