The targets lie near the intersection of faults. Illite clay has been identified as the alteration mineral in the archived core from hole GS-3 and the archived core contains some uranium values which, importantly, occur with a suite of chemical.
The unconformity-related deposits in the Athabasca basin typically straddle old thrust faults that were active during basin formation. Bore hole GS-3 intersected a thrust fault that corresponds with an east-trending regional fault that is evident in magnetic data.
Many deposits in the Athabasca basin are located near the intersection of older thrust faults with cross-cutting structures. Magnetic data show the older thrust fault that was cut in bore hole GS-3 intersects a younger northeast-trending fault about two kilometres east of the bore hole collar.
Sandstones and conglomerates in hole GS-3 contain illite clay alteration. Illite typically occurs in the outer parts of alteration systems associated with Athabasca-type deposits.
Chemical elements that are typically concentrated in or near uranium deposits in the Athabasca basin have been identified in core from bore hole GS-3.
At 148-156 metres depth below surface, uranium values of six and 19 parts per million (ppm) were detected with anomalous levels of chromium and zinc within a halo of elevated bismuth, vanadium, zirconium and titanium. These elevated values occur directly beneath a silicified zone.
Comparable zones of enriched chemical elements beneath silicified layers in the Athabasca basin are ascribed to metal-bearing fluids pooling against impermeable silica-sealed barriers during hydrothermal activity that may have been related to the formation of adjacent uranium deposits.
Similarly, rocks with more than 10ppm uranium seldom extend more than a few hundred metres from deposits such as Cigar Lake in the Athabasca basin.
The unconformity at the base of the Roraima is located at a depth of 301 metres in bore hole GS-3. Another zone with elevated metal content – lead, zinc, cobalt, bismuth, vanadium, titanium, zirconium and, straddles the unconformity (290-311 metres).
U3O8 interpretation is that the illite-dominated alteration in hole GS-3 and its anomalously high pathfinder chemistry represent the outer part of a hydrothermal system similar to those that enclose unconformity-related deposits in the Athabasca.
The company said that by analogy with the Athabasca, the target areas for unconformity-related uranium are likely to be near the intersection of faults such as the east- and northeast- trending faults that lie within the weakly magnetic zone east of hole GS-3. This focuses exploration on two specific target areas that cover one to 2sqkm each within the broader weakly magnetic zone.
