Geostatistical methods for estimating iron, silica and aluminium within iron ore deposits:- a case study of the Mount Tokadeh Study Area, Yekepa, Yarmein District, Nimba County, Republic of Liberia

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Mining history in Liberia is often plagued with difficulties of uncertainty of commercial quality and quantity of mineral existence in a particular region. Previous studies conducted at Mount Tokadeh, study area which lies between latitude 7 o 15’N and 7 o 45’N and longitude 8 o 15’W and 8 o 45’W was distributed in three ore zones; the Oxide Ore, Transitional Ore and Primary Ore. It was also proven that there is some considerable amount of silica and alumina in this ore deposit bu t the extent of these impurities within this ore deposit were unknown. The main aim of this research was to investigate the use of information gain from kriging interpolation techniques (Ordinary Kriging, Indicator Kriging and Universal Kriging) to estimate iron ore resources and categorize selective mining unit as High Grade Ore (HGO) or Direct Shipping Ore (DSO). Field data were processed in excel template and exported into shapefile format inputted into ArcGIS/Arcmap 10.2.1 for interpolation using t hree main kriging interpolators. Four classes of creative colors were used to delineate the relative quality of mineral distribution within mining site. The final output maps (Prediction map, Probability map and Error of Prediction map) were obtained. Voxler was used to model borehole data in 3D format and was overlayed on the output kriged map for validation. The results showed that Indicator Kriging which uses threshold was the best interpolation method that categorizes the various mining units. Integrated method using Kriging in GIS was introduced and implemented in this work to determine the prospect of using this approach in mapping the spatial division of iron, silica and aluminum content and tonnage of iron ore.
The thesis submitted to The Department of Geomatic Engineering, College of Engineering in partial fulfilment of the requirement for the degree of Master of Science, 2016