Infill drilling at Eagle Mountain’s Oracle Ridge mine project in Arizona has uncovered a significant prize – a previously unrecognised, thick zone of copper.

A single hole might be a fluke, but all five infill holes completed to date have intersected this zone within the existing JORC resource.

This includes a highlight 18.4m at 3.12% copper, 27.83 grams per tonne (g/t) silver and 0.51g/t gold from 53m, located within a thicker 110.1m interval grading 1.06% copper, 9.64g/t silver and 0.16g/t gold.

This intercept is consistent with results from the other four holes.

The zones include both higher and lower grade material that gives Eagle Mountain (ASX:EM2) optionality for future mining, while the results also provide sufficient confidence to allow for high certainty ‘measured’ resources to be defined in the next resource update.

The highlight hole mentioned above also ends in mineralisation, with the last 0.9m returning 3.63% copper, 65.7g/t silver and 0.53g/t gold before piercing through into the historical mine.

Assays are pending for a further 18 holes.

Chief executive officer Tim Mason said the results came as a surprise to the company as many of these zones were not previously assayed by previous owners, who had typically focused their efforts on higher grade mineralisation based on visual identification.

“From a mining perspective, thick zones of mineralisation provide potential for bulk mining scenarios or using ore sorting technology to separate barren rocks from copper bearing ores to reduce processing costs,” he said.

“The intercept of 18m at 3.12% copper and 0.51g/t gold, within a much larger mineralised zone, is one of the best intercepts at Oracle Ridge.

“In addition, the overall gold grades in the reported infill holes are, on average, better than those in surrounding historical holes.

“We are excited by these results, because if the presence of these thick zones is extensive it could materially improve the contained copper in resource and provide optionality for future mining methods and production rates.”

eagle mountain
Plan view of recent drilling results at Oracle Ridge. Pic: Supplied

Oracle Ridge and upcoming activity

Oracle Ridge is in an established copper district, with 18km of pre-existing underground workings close to its existing resources.

It was last mined in the 1990s and acquired by Eagle Mountain in November 2019.

Drilling outside the existing JORC resource of 12.2 million tonnes grading 1.51 per cent copper, 16g/t silver and 0.19g/t gold — which is hosted in four stacked lodes and extends more than 2km from north to south and is open in all directions — has already returned notable results.

Additionally, drilling at the ‘Western Talon’ area had intersected four high-grade lodes earlier this month, leading Mason to say that it is a potential game-changer, an attitude that has undoubtedly being reinforced by the thick mineralised zone intersected in infill drilling.

These results indicate that lower grade mineralisation (relative to the high-grade zones) is present in zones that were considered barren by previous operators.

Not only could this previously unknown resource increase overall resources at Oracle Ridge, but it could also prompt a shift from the currently envisaged underground mining method towards a less selective, bulk mining scenario.

Eagle Mountain is currently planning to drill more resource upgrade holes to assess potential for thicker zones of mineralisation.

It is also preparing to carry out metallurgical testwork to assess recoveries from the thick mineralised zones.




This article was developed in collaboration with Eagle Mountain, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.