Preliminary Investigation of Trace Elements Concentration in Dust from Tin Processing Mills in Jos - Bukuru Area, Northcentral Nigeria

Abstract

The Jos – Bukuru Biotite Granite is the largest of the biotite granite belonging to the Younger Granite province of Nigeria. The rock hosts the tin and columbite mineral which on weathering released them forming the alluvial deposits mostly along stream channels. These minerals were extensively mined in the early 19^th century and remained active until late 1970s. Mining and processing of these minerals is still ongoing but on smaller scales around the Jos – Bukuru area. The aim of this work was to determine the concentration of trace element in dust generated during milling and processing of Tin and associated minerals. Fifteen dust samples were collected during the air floating and after floatation operations in nine different processing sites by placing filter papers at designated locations. Dust samples were analysed by Inductively Coupled Plasma Optical Emission Spectrometry. Generally, in all the processing mills Pb, Zn, Th, U are quite high. Pb ranges from 204.5 – 1177, Zn, 67.0 – 1,272, Th > 200 in all samples, U, 186.5 – 1623, As, 0.3 – 233.7 ppm respectively. Anthropogenic factor and index of geo-accumulation calculated for some of the trace elements indicate that the contamination level of trace elements ranges from uncontaminated (Ni), Uncontaminated to moderately contaminated (V, Co, Fe, Cr, Ti), contaminated to highly contaminated (Cu Se, Pb, U, Th, Zn, As and Mo). The use of mask to cover the nose and other protective clothing for other parts of the body during floating operations is not practiced, hence inhalation of this dust by workers posses a great risk to health.

Keywords: Younger Granites, Columbite, Tin, Dust, Anthropogenic, Geo-accumulation, contaminated