Rockmass Classifications and Probability Distribution Functions of Intact Rock Properties of an Open Pit Mine, Ebonyi State, Nigeria

This paper present the results of rock mass classification of Eyigbashales hosted lead zinc open pit mine and probability distribution functions of intact rock properties from laboratory experiment. The studylocation is within Ikwo and Abakaliki Local Government Areas of Ebonyi State between latitude 6°09’ and 6° 14N and longitude 8°05’E and 8° 10’E longitude The objectives are to map (scanline method) the discontinuities (joints, faults, folds) cut across the eastern part of the mine, classify the rock mass and performed montecarlos simulation on the intact rock properties from laboratory experiment to produce probability distribution functions of these properties. Rock mass rating (RMR), Rock quality designation (RQD), and Q system are the rock classifications system used in the assessment of the rock mass quality. RMR, Q and RQD confirmed that the rock quality is Fair. There are variations in the properties of the intact rocks, where only a single (deterministic) value cannot sufficient represent these properties. Consequently, the used of probabilistic distribution method is suggested and applied to quantify the uncertainty and variability of these properties. The results can served as input parameters for the determination of the rock mass properties and in numerical modeling operations.