Altona Mining smells the Roseby
THE DRILL SERGEANT: Perth-based copper exploration play Altona Mining has upgraded the resource at its 100% owned Roseby project in Queensland.
The global resource estimate for the project has increased to:
– 177 million tonnes at 0.6% copper and 0.06g/t gold for 1.1 million tonnes of copper and 296,000 ounces of gold.
Altona said the new estimate represents a 20% increase in contained copper metal and is a result of a new estimation of resources at the Little Eva copper-gold deposit.
The revised Little Eva resource is:
– 74.7 million tonnes at 0.52% copper and 0.1g/t gold for 388,000 tonnes of copper and 205,000 ounces of gold above a cut-off grade of 0.2% copper.
Just over half of this estimate is in the Measured and Indicated categories.
The company said it expects to receive further resource upgrades at Little Eva, as only 11 of 53 holes drilled in the current drill program have been included in this estimation.
Little Eva has now established itself to be the largest deposit at Roseby having been drilled to depths of 200 metres – 250 metres.
According to Altona it is steeply dipping, 1.3 kilometres long and ranges from 20m to 360m wide.
The deposit is not fully defined along the western edge and remains open to the southeast.
Altona has yet to commence any drilling or re-estimation at the other Roseby deposits, which it said currently contain over 100 million tonnes at approximately 0.60% copper and 0.05g/t gold.
“Little Eva is a typical IOCG (iron-oxide copper-gold) deposit,” Altona Mining said in its release to the Australian Securities Exchange.
“It is a large and simple copper-gold deposit which has excellent metallurgical recoveries of copper (95%) and gold (94%) to concentrate.
“Prior studies indicate that processing will be via an industry standard flotation plant to produce a copper-gold sulphide concentrate. A 15-30 metre thick cap of oxide copper mineralisation (goethite, malachite, etc) overlies primary mineralisation (feldspar-quartzhematite- carbonate-chalcopyrite).”
Altona said the resource has come about through a range of new information the company acquired since a prior estimate, which was updated in 2005.
This information included metallurgical and geotechnical diamond drill holes, some of which had not been assayed.
It also contained the first 11 RC drill holes of a current drill program, as well as a new geological model utilising a geologically relevant cut-off grade and improved estimation techniques.
“The difference in the estimate is largely due to the extension of prior resource boundaries and the application of lower cut-off grades, commensurate with increased commodity prices since the last estimate,” Altona said.