Macphersons targets Nimbus East tailings

THE DRILL SERGEANT: MacPhersons Reward Gold has completed preliminary sampling of the Nimbus East Pit tailings storage facility (TSF) at its 100 per cent-owned Nimbus project, located near Kalgoorlie in Western Australia.


View of Nimbus Silver Mine, current mill processing site and East
Pit showing first two composited test sites labelled as “C” and “P”
representing the central and perimeter sites respectively (red
triangles). Source: Company announcement


According to the company’s ASX announcement the sampling has provided it with better results than were expected.
The results have encouraged MacPhersons to drill out the East Pit TSF on a 10 metre by 10 metre grid pattern to allow the company to complete a processing feasibility study during the first quarter of 2012.

Drilling of the TSF is being carried out using two rigs.

An auger rig is drilling the TSF section that is less than 20m thick, while diamond drilling is being conducted through the deeper central TSF zone, with diamond holes casing off and commencing a grade control drill out of the pit floor.
“The first pit floor diamond hole has been completed through 23 metres of tailings and then continued to intersect several stockwork and massive sulphide zones down to a depth of approximately 140m (approximately 120m beneath the pit floor),” Macphersons reward Gold said in its announcement.

Preliminary results from the first two composited bulk samples included:

–    Assay results of all samples ranged from 19 grams per tonne to 211 grams per tonne silver;

–    The central zone composited metallurgical head grade ranged from 147g/t to 164g/t silver;

–    The perimeter zone composited metallurgical head grade ranged from 112g/t to 127g/t silver;

–    Leach testwork on composite samples grading 113g/t to 140g/t silver had recoveries of between 88 per cent and 91 per cent; and

–    Surveying of the East Pit TSF gave a calculated tonnage of between 125,000 tonnes to 135,000 tonnes of material.

“No testwork has been commenced on the larger Nimbus TSF#1, which has an estimated 190,000 to 200,000 tonnes of tailings material at an historical grade estimate of between 20 grams per tonne to 100 grams per tonne silver,” the company said.

“The Directors believe that the Nimbus East Pit tailings represent a near-term silver production opportunity.

“The East Pit TSF testwork and a JORC mineral resource statement will be completed in Q1 2012.”