Discovery, depth of occurence and thickness estimation of Pb-Zn-Fe(S) mineralisation in Nigeria: a case study of Ndikpa, Ebonyi State SE, Nigeria

Abstract

The lead-zinc-Iron (sulphides) mineralization within Ndikpa has been studied. The study is in response to the demands of Aubel Mining Plc. Nigeria, to undertake a geophysical investigation of the mining lease (ML17436, P.R. No. 8/96) located at Ndikpa for the possible Pb–Zn–Fe (s) mineralization. The area is located between latitude 6039N and longitude 80 310E and falls within the southern part of the Benue trough of Nigeria. The trough is a sediment filled graben which is an aborted arm of a triple rift system associated with continental drift. Geologically, Ndikpa falls within the lower Cretaceous sequence of south Eastern Nigeria, corresponding to the Albian age. The formation consists predominantly of shale and silt stones, a sequence with an estimated thickness of about 1500 meters and deposited unconformably on the subsiding basement and was deformed during the Cenomanian time. The self potential (Sp) and resistivity methods were employed to find out the areas of lead-zinc-iron (sulphides) mineralization, thickness, and depth of occurrence. The instruments employed include scintrex resistivity and Sp unit (RSP 6), Digital Adler Stratameter and Sp Geometer. Traverses were run in the E-W direction covering the lease boundaries. A total of 23 Sp traverses were covered at 30 meters traverse interval. VES traverses were run at locations of interest based on favourable Sp responses. The results of the survey indicate that the Pb-Zn-Fe(s) mineralization is associated with the anticlinal axis and are discontinuous in a N-S direction. The thickness of the ore veins measures 19.0meters and confined within the shales at an average shallow depth of about 21.08meters.

Global Journal of Pure and Applied Sciences Vol. 11(4) 2005: 535-541