Discovery Metals Limited said final results from its Zeta underground infill drilling has endorsed the potential of a future underground mining for its project situated in the north-west part of Botswana.
The Managing Director of the Botswana Stock Exchange (BSE) quoted outfit, Brad Sampson, praised the results as they contain large mineralisation.
“The final assay results from the infill drilling programme confirm the results of all previous drilling, and demonstrate that the Zeta deposit contains a thick zone of mineralisation (over 10 metres), with a high grade core (+2% Cu ),” he said.
The results reported are from the last 18 holes of the infill drilling programme, which will form part of the Zeta underground mining Definitive Feasibility Study (DFS).
These 18 holes complete the infill drilling programme at Zeta, and all assay results will now be incorporated into an updated Mineral Resource estimate of the deposit, which is due for completion in second quarter of 2011.
In total, 54 holes were drilled in this programme. Eleven of the holes were extended into the footwall stratigraphy by at least 40 metres to gather geotechnical information for the preparation of an underground mine design plan.
Zeta is a part of the 100 percent owned Boseto copper project, which is currently being constructed and is scheduled to commence production in early 2012. Planned at the mine are 36,000 tonnes of copper and 1 million ounces of silver per annum over a minimum 15 year mine life.
A review of results indicates that the average drilled thickness of the Zeta deposit beneath the planned open pit is more than 10 metres, at an average grade of 1.3 percent copper and 26.2 g/t silver.
“The results endorse the potential of a future underground mine at Zeta ? which in
turn bodes well for our goal to increase production at Boseto beyond the currently planned 36,000 tpa Cu,” added Sampson.
The three best intercepts reported in the results were drilled beneath the area of the planned open pit, over 600 m of strike, where the best mineralised zone is developed.
The remainder was drilled at the southwest end of the deposit, where we now believe economic potential has been closed off.
All holes were aimed to intersect mineralisation between approximately 200 and 300 metres below surface (to the 675m RL). Excluding those holes at the southwest end of the deposit, the drilling programme has demonstrated that the Zeta deposit has an average drilled thickness of more than 10 metres (┬▒6m true thickness) and an average grade of about 1.3 percent copper, over approximately 1.8 kilometres of strike, to a depth of approximately 300 metres below surface.
A scoping study into underground mining at Zeta (reported in March 2010) indicated that large scale underground mining (up to 1.5 million tonnes per annum of ore production) was possible from an Indicated and Inferred Mineral Resource of 25 million tonnes at a grade of 1.4 percent copper and 23.1g/t silver.
This Mineral Resource was contained along approximately 6 kilometres of strike and to approximately 400 metres below surface.
The study determined that an optimised underground mine base case would produce 9.5 million tonnes at 1.4 percent copper and 19.2 g/t silver over an eight year mine life, with mining occurring over approximately a 2 kilometre strike length.