Designing controlled blasting in the vicinity of sensitive structures in an iron mine in India: A case study

Abstract

This paper presents a case study at an Indian iron ore mine where controlled blast patterns were meticulously planned after conducting a few trial blasts for conducting blasts near numerous sensitive structures. A new screening plant for the mine had to be constructed on a hilly terrain in the vicinity of many sensitive structures such as residential huts, gas stations, gas storage facilities, structures of the existing screening plant, mine water reservoirs, etc. The test blasts were conducted at selected locations of the hilly terrain with varying geometric parameters in order to understand the results of the interaction between rock and explosives in the area. The effects of blasting, i.e., ground vibration, air overpressure, rock flight, etc., were evaluated and measured. Based on the results the results of test blasting and vibration data analyses from various iron ore mines in India with similar topographic conditions, three blasting zones were distinguished: critical, semi-critical and non-critical have been defined considering the nearness and sensitiveness of different structures. For each zone, the blasting parameters were developed, i.e., load, spacing, number of holes, blast charge per delay, type of explosive, etc. Using the developed controlled blasting patterns, development work near sensitive structures progresses safely. The developed controlled blasting patterns and methods can be used as AIDS for similar work in the absence of adequate scientific evaluation results.