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Article 1 - Volume 35/2 - 2025

Paper title:

Application of Geostatistics to Mineral Resource Modeling and Estimation: Case Study of Gofolo Hill Iron Ore Deposit, Western Liberia

Author(s):

Leo KLAH-WILSON1, Aaron K. WASWA1, Daniel W. ICHANG'I1

1 Department of Earth and Climate Sciences, University of Nairobi; Nairobi, Kenya

Pages:

1 - 21

Publishing date:

19 June 2025

Abstract:

Geostatistical methods are essential in accurate mineral resource estimation, as they account for spatial correlations and uncertainties. This study evaluates the mineral resource of the Gofolo Hill deposit in Western Liberia using the ordinary kriging method, and in addition, applies two traditional estimation methods, the inverse distance weighting method and the nearest neighbor polygon method, for comparative analysis. The study uses 39 reverse circulation drill holes with 200m x 60m grid spacing. The ordinary kriging method estimated a resource of 17.169 million tonnes with an average grade of 35.90%. In comparison, the inverse distance weighting method estimated 16.975 million tonnes at an average grade of 35.53%, while the nearest neighbor polygon method estimated 14.757 million tonnes at an average grade of 38.55%. The results show that the ordinary kriging method provides the most accurate estimates, followed by the inverse distance weighting method, with the nearest neighbor polygon method showing the least precision. The findings emphasize the importance of a geostatistical approach in resource estimation and support their application in mineral evaluation.

Keywords:

Iron ore, Gofolo Hill, Resource estimation, Ordinary Kriging, Inverse Distance Weighting, Nearest neighbor polygon