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US Red Hills Deposit mineral resource estimate completed

23 February 2012

Tosco Mining-Feb 23

Tosca Mining has announced that Mine Development Associates (MDA) has completed a NI 43-101 compliant mineral resource estimate for the Red Hills Deposit, located in Presidio County, Texas, the US.

The MDA report said the mineralisation of interest at Red Hills occurs within a porphyry molybdenum deposit and near surface copper enrichment zone that spans an area about 4,000ft by 3,000ft.

With a depth-extent of over 2,000ft, the porphyry molybdenum mineralisation is not well-defined past a depth of 1,000ft. Both copper and molybdenum mineralisation are open to the south under post-mineralisation cover.

Nevada-based Tosca Mining CEO Sadek El-Alfy said: "The results from the 2011 diamond drill campaign confirmed that Red Hills is a large porphyry deposit with commercially attractive grades of both molybdenum and copper. Metallurgical studies have shown that recoveries of this molybdenum/copper resource are encouraging and straightforward.

"In 2012 we will continue to develop Red Hills by investigating the economic feasibility of molybdenum/copper extraction and recovery on a large scale; this study will be incorporated in a preliminary economic assessment (PEA) currently being prepared by M3 Engineering in Tucson, Arizona.

"The company is planning a drill program to upgrade the resources and to drill test the potential southern extension of the deposit"

The Red Hills Deposit mineral resource estimate is based on a database of 121 drill holes totaling 60,131ft, which includes 53,947ft of diamond drilling.

By using Gemcom Surpac mining software, the modelling of the Red Hills Resources was performed under which lithology, oxidation, and copper-molybdenum mineral domains models were created.

The Red Hills resource was constrained to a bottom elevation of 2,800ft, approximately 1,200ft below the general surface, and is fully diluted to 20ft by 20ft by 20ft blocks.

MDA has reported the resources at a cut-off grade (0.025% MoEq) because of the requirement that the resource exists 'in such form and quantity and of such a grade or quality that it has reasonable prospects for economic extraction'.

A significant tonnage of molybdenum-only material in the resource has been reported, with the copper resource fully contained within the near-surface copper blanket.

Multi-element analyses of Tosca's drill samples also show elevated rhenium levels associated with molybdenite mineralisation.

A froth flotation study was conducted by METCON on seven composite core samples from Tosca's 2011 drilling at Red Hills, using assay rejects.

Image: The mineralisation of interest at Red Hills occurs within a porphyry molybdenum deposit to a depth-extent of over 2,000ft.Photo: Tosca Mining.