UTILISATION OF GEOMECI-lANICAL PROPERTIES OF ROCK FOR EFFICIENT FRAGMENTATION (A CASE STUDY OF NATIONAL IRON ORE MINING COMPANY, ITAKPE. KOGI STATE)

Abstract

Rock blasting is by nature a highly destructive process demanding careful control. Rock, which is under blasted, can add significant problems and costs to a mining operation. Poorly managed drilling and blasting operations often result in fragments that required secondary handling for effective mining. They generate boulders that create both environmental and communition problems. Careful studies were made of drilling and blasting operations at Itakpe taking into cognizance the properties of the ore and the host rocks as well as the explosives used. Steps were taken to identify those parameters that have the most significant influence on blasting results, and proposals made. The proposed methods improve fragmentation for the processing plant and render the environment tolerably safe. Laboratory experiments and tests were conducted and the results shows that approximately 80% of the blasted ore sized between 1000mm and 800mm. Attention was paid to the fragment size that occurred during blasting. Drilling and blasting techniques of the company were studied, the problems identified and proposals made on how to achieve production efficiency. The optimization process of, -drilling and blasting establish the influence of materials related properties in the overall design processes for safe mining. These were investigated under the prevailing conditions at the mine. A suitable method to calculate new diameter, burden and spacing utilizing the existing bench height was proposed. From the laboratory experiments, it was established that drill ability and blast-abiltiy classification of rock mass has not only revealed the characteristics of the ore, it has also been able to predict the quality of blasting results. The result also established that the geomechanical characteristics of the ore exercise more influence on the result of rock blasting than the explosive ones.