Earth Sciences Pakistan (ESP)

This research compares ordinary kriging (OK) and inverse distance weighting (IDW) techniques in the estimation of volume, tonnage, average grade, and ounces of gold within the alluvial gold deposit located in the northern part of the Kibi-Winneba gold belt, Ghana, to ascertain the technique that yields results that align more closely with actual production values. The deposit contains fine nuggets of gold in gravel profiles covered by sharply contrasted overburden materials. Overburden and gravel layers from 219 hand-dug pits were logged, while the gravel portions were sampled and assayed by washing to determine the gold grade of each pit. Implicit modelling of the deposit using wireframes was carried out in Datamine Studio RM software. The block model and resource estimates were compared and accurately reflected the input sample grade. At a cutoff grade of 0.4 g/m3, the resource has 12.453 million cubic metres of auriferous gravel at an average grade of 0.51 g/m3. This is expected to produce about 204238 ounces of gold after mining and extraction. Different block models and resource estimates using the inverse distance weighting (IDW) approach were used to compare the OK estimate. The IDW2 correlated well with the OK model. Hence, a resource estimate was generated using the IDW2 and the difference in the expected ounces of gold was calculated to be 2.02% lower than that of the OK estimate.