• Channel sampling in highest level of Oracle Ridge returns up to 15.3m at 4.02% copper
  • Result is the strongest underground channel sampling result returned to date
  • Sampling results will be incorporated into resource upgrade on track for Q4 release


Underground channel sampling from the highest level of Eagle Mountain’s 16.5Mt Oracle Ridge project have returned the strongest result to date – 15.3m at 4.02% copper.

Oracle Ridge is a previously producing underground mine less than two hours’ drive from Tucson, Arizona, and just half an hour from the mining town of San Manuel, placing it in the perfect position to feed US demand for the red metal.

The US is looking to achieve 100% clean electricity by 2035 and large quantities of copper will be required to achieve this goal – a level of demand that is likely to challenge existing supplies given the paucity of new copper mines.

The project also benefits from some 18km of existing underground development and extensive local infrastructure.

Eagle Mountain Mining (ASX:EM2) is currently in the process of updating its resource estimate for Oracle Ridge, which currently stands at 16.5Mt grading 1.45% copper, 15.1 grams per tonne (g/t) silver and 0.19g/t gold, for contained resources of 240,000t of copper, 8Moz of silver and 102,000oz of gold.

To achieve this, the company is utilising both drilling (surface and underground) and channel sampling, whereby a channel is cut across the vein or orebody for the most representative samples possible:


Eagle Mountain Mining ASX EM2
Underground channel sampling using “herringbone” sampling pattern. Pic: Supplied (EM2).


Newest results from the highest level of the mine (6550) – including 15.3m at 4.02% copper, 18.71g/t silver and 0.14g/t gold — are the best so far, building on the “extensive and consistent upside” previously reported for the two lower levels (6500 and 6400).

Intercepts from 6550 are both wide and high-grade, with most channels hosting mineralisation across the entire channel length. Other new assay results received include:

  • 35.7m at 2.60% Cu, 14.86g/t Ag and 0.08g/t Au;
  • 19.2m at 3.32% Cu, 37.66g/t Ag and 0.31g/t Au;
  • 30.5m at 1.50% Cu, 18.44g/t Ag and 0.20g/t Au; and
  • 27.1m at 1.67% Cu, 19.88g/t Ag and 0.19g/t Au.

On average, channel samples have reported higher grades compared to nearby drill holes, the company says.

All up, the consistently high grades and widths seen from channel sampling to date cover an approximate area of 150m by 120m across three underground development levels.

Previous drilling has also identified broader, lower-grade ‘haloes’ surrounding these high-grade copper zones which could support bulk mining and processing methods if they prove to be extensive.


Better than ever

These latest channel sampling results provide a high degree of confidence that the coming resource upgrade, which is on track for release in the fourth quarter, will be significantly higher than the current resource.

“It is fantastic to see that Eagle Mountain’s third set of channel sampling results are the strongest to date in terms of average grade and width,” chief executive officer Tim Mason said.

“These great results support the updated resource model, with the sampling programs providing increases to the higher-grade portions of the resource.

“The new results and the positive surface and underground drilling completed since October 2022 will be incorporated in the upcoming resource update.”

Mason added that successful exploration to date has increased the company’s knowledge of the resource and has provided substantial optionality for future mining and processing scenarios at Oracle Ridge, which will allow for optimisation of its development and maximise value.


Forward plan

Eagle Mountain is now incorporating detailed underground geological mapping acquired during the sampling programs into a revised geological model.

This includes structural measurements, the extent of visual sulphide mineralisation, lithological contacts and alteration zones.

All drilling and channel sampling results – as well as the revised geological model – will be incorporated into the resource update.

The company is also continuing to progress technical evaluations, analysing the project’s strengths and optionality with mining and processing.

Extensive copper mineral speciation analyses are continuing to better understand and optimise future metallurgical test work.



This article was developed in collaboration with Eagle Mountain Mining, 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.