Exploration trenches for uranium resource evaluation

Abstract

The Jordanian Uranium Mining Company (JUMCO) needed to determine the most appropriate method for sampling and assaying the surficial uranium deposits of central Jordan. This type of mineralisation presents a number of challenges including; i. occurrence of best mineralisation within 5 m of surface, ii. observed secular isotopic disequilibrium, iii. erratic distribution of uranium mineralisation, iv. problems with drill sample recovery close to surface, v. difficulty in reliably logging geology in percussion drill chip samples. Previous exploration drilling programs that relied on gamma logging were shown to be unreliable because of secular disequilibrium close to surface. The percussion chip samples used for chemical assaying were shown to be unreliable because of poor sample recoveries and the possible loss of fine-grained uranium mineralisation. In an effort to maximise sample recovery, avoid disequilibrium problems and assess the short-scale continuity of mineralisation, trenching was chosen as the preferred exploration method to evaluate the upper part of the surficial uranium deposits of central Jordan.