Reserve Estimation of Barite Deposits Using Geological and Geophysical Investigations in Cross River State South Eastern Nigeria

Barite deposits occur mostly as concealed mineralization dominantly in shales and sandstones of Cretaceous age in Cross River State. Vertical Electrical Sounding (VES) and Horizontal Resistivity Profiling (HRP) have been carried out in areas with less mining activities. Also, field geological mapping in which the lengths and the widths of barite veins were measured has been undertaken.The geophysical data collected within 22 communities was done in 52 locations and the results indicate that the barite occurs in veins located at 10 – 12.2m depth and could be up to 40m in open mine pits. The lateral extent of the veins range from 4m to 65m from the from the horizontal resistivity profiling results, and could be traced from the field mapping to about 950m . The general direction of the barite mineralization is NE-SW . The result of the reserve estimate indicate that the Agoi village of Oban Massif has 1,981,177.0 metric tons of reserves, these are greater than the reserve found at mamfe embayment villages of Ekukunela and Nkarasi with reserve deposits of about 865, 684 metric tons. These reserves are also greater than those found in parts of the lower Benue trough villages of Osina and Okpoma (Ogoja) with reserve deposits of about 774, 345 metric tons. An estimated reserve of over nine (9) million metric tons of barite have been calculated and documented for Cross River Stat for the first time. This has unarguably put Cross River State as having the largest reserve of barite in Nigeria. KEY WORDS: Barite, VES, HRP, Reserve, geophysical