MAPPING AND CHARACTERIZATION OF SOLID IRON ORE MINING WASTES IN KISHUSHE AREA, TAITA TAVETA COUNTY, KENYA

Abstract

Solid mine waste management is a continuous and systematic assessment of the potential hazards, disposal, and proper utilization of waste produced in a mining company during the mining and mineral processing stages. In the mining industry, solid mine waste is generated at every stage of operation and must be disposed of properly. There is a need to understand the solid mine waste composition in depth and know the extents they cover at a mine. Solid mine wastes can affect the environment through their intrinsic properties. Therefore, proper assessment of these solid wastes is essential in waste management. This study was done at Samruddha Resources Limited Iron Ore Mines in Taita Taveta County, Kenya. The main objective of this research was to map and determine the environmental pollutants in the solid mine waste produced during iron ore mining and processing. This was achieved by utilizing geochemistry, mineralogy, Geographical Information Systems (GIS), and Remote Sensing techniques. Geochemistry and mineralogy of the solid mine wastes were determined by X-ray Fluorescence (XRF), X-ray Diffraction (XRD), and Petrographic Analysis. The extent and the volumes of the solid mine waste were mapped using GIS and Remote Sensing techniques utilizing the surface volume differencing method and Maximum Likelihood Classification (MLC) at an accuracy of 74%. XRD studies revealed Magnetite 𝐹𝐹𝐹𝐹3 𝑂𝑂4 and Hematite 𝐹𝐹𝐹𝐹2 𝑂𝑂3 were highest at 29% and 21%, respectively, with subordinate amounts of Quarts and Calcite in stockpile samples. Quartz concentration was high (43%) in waste dump samples and Berlinite (33%) and Quartz (31%) in high concentrations in the overburden samples. XRF studies indicated high amounts of iron in the stockpile (80%) and waste dump (36%). Silica was in excess of (41%). Potentially toxic elements such as Zinc, Lead, Chromium, Titanium, iii Manganese, and Copper were in considerable amounts in all the samples. Petrography analysis results indicated the major minerals in the solid mine wastes to be magnetite, hematite, and quartz with traces of mica, feldspar, and biotite and intrusions of pyro garnets and olivine. The minerals are characterized by a lamellar structure with grains boundaries between individuals being mutual. It was observed that the solid mine wastes covered an estimated total area of 591,100 𝑀𝑀 2with a volume of 523,237.11 𝑀𝑀 3 . This research pointed out pollutants in the solid mine wastes and the unregulated dumping of solid mine wastes. Therefore, proper solid mine waste management can be improved by improving mining and processing methods to mitigate waste and subsequently exploit the value of these wastes