Northern Uranium Limited (Northern Uranium) has discovered significant uranium intersection in an early stage of diamond drilling program on its 100%-owned Gardiner-Tanami project in Western Australia. The drilling follows two years of geophysical surveys and ground geological reconnaissance covering 6,000km2 of tenements targeting the high grade unconformity-related uranium deposit type.
French nuclear group Areva NC is the operator of the project through its wholly owned Australian subsidiary Afmeco Mining and Exploration Pty Ltd (Afmex).
Three holes have been completed, with the second hole successfully validating Afmex’s exploration strategy by intersecting a narrow zone of uranium mineralisation at a depth of 146.8m below surface. The mineralisation is closely associated with an oxidised fracture zone located below a graphitic conductor.
Downhole gamma logging returned values up to 120ppm eU3O8 from a 10cm thick brecciated zone. A portable hand-held XRF recorded up to 550ppm uranium and 400ppm copper in spot measurements on fractured rock coatings, confirming the occurrence of uranium. In the vicinity of the anomalous fracture zone the host rock displays an apparent bleaching, with evidences of drusy quartz along fractures. In the first instance the mineralisation is interpreted to be related to hydrothermal circulation, lately remobilised by weathering processes.
Kevin Schultz, executive chairman of Northern Uranium, said the results were a promising start to the maiden drilling program on the company’s flagship Gardiner-Tanami project. “These observations are highly significant and confirm the validity of the exploration approach implemented by Afmex, and the geophysical work completed to date,” Schultz said. “The current drilling is early stage and broadly spaced, so Afmex deserves credit for making a uranium hit in only the second hole. These early indications will be followed up but the priority depends on the results of the remaining holes of this program.”
Distinctive basement rocks, such as graphitic metapelites, are considered as the reducing components implied in unconformity-type deposit formation and being conductors they can be targeted with geophysics. Uranium deposits form by the mixing of oxidised and reduced basement fluids within fault structures and zones of fracturing and brecciation in the vicinity of the unconformity,
“To encounter these conditions in only the second hole drilled is very encouraging,” Schultz said.
Northern Uranium recently completed a $2.2 million share rights issue, with the funds primarily being used for ongoing drilling and exploration activity at the Gardiner-Tanimi project.
For logistical reasons the first two holes were drilled in the Lewis Creek North area which features surface uranium radiometric anomalies and VTEM (Versatile Time-Domain Electromagnetic) conductors on favourable structures at or near the Gardiner Sandstone unconformity. Both holes at Lewis Creek intersected numerous graphitic conductors within the Killi Killi beds, with the second hole (GT02) intersecting anomalous uranium in a breccia zone below a graphitic conductor.
Ground radiometric surveys and detailed geological mapping have now been completed in the area around GT01 and GT02 outlining new anomalies to be followed up.
On completion of the two Lewis Creek North drill holes, the diamond drill rig was moved to Oracle-Soma area, which is in the vicinity of “The Don” prospect, a 1980s primary uraniumgold discovery. Oracle-Soma is the Company’s highest priority target area, As was the case at Lewis Creek, logistics dictated a lower priority diamond drill hole was drilled first, in search of water as well as testing a conductive geophysical target. The hole, GT03, has been completed but failed to intersect any significant graphitic metapelite.
Hole GT04, the nearest of all of the holes in the current program to The Don prospect, has now commenced. This hole is collared on top of the Gardiner Sandstone. Drilling will test the unconformity as well as a deeper VTEM conductor.
Additional drill holes are proposed in the Oracle-Soma area in the current program and further results will be reported as they become available. More holes have also been planned for the Lewis Creek North area but the late start to the program may mean a delay due to seasonal conditions.