Partners prove up copper potential at Pyramid project

VANCOUVER — It took less than three years and only 30 holes for Full Metal Minerals (FMM-V) and Antofagasta (ANTO-L) to define a resource at their Pyramid project in Alaska that contains more than 1.3 billion lb. copper, as well as notable molybdenum and gold.

Antofagasta signed on as a joint-venture partner at Pyramid in late 2010, and has since spent more than $6 million exploring the site. The effort has since produced two results: Antofagasta has earned a 51% stake in the project and defined an initial inferred resource.

Pyramid is home to an inferred resource of 173 million tonnes grading 0.35% copper, 0.02% moly and 0.088 gram gold per tonne. The project partners describe the deposit at Pyramid as a sediment-hosted quartz-diorite porphyry.

The deposit at Pyramid bears classic porphyry characteristics, with a leached cap covering a supergene enrichment blanket that overlies a body of hypogene mineralization. Copper leached from the oxide cap has been redeposited in the supergene layer, resulting in a 93.7-million-tonne supergene resource that grades 0.4% copper, 0.019% moly and 0.092 gram gold.

Mineralization in the supergene blanket is dominated by chalcocite and local covellite. The blanket’s depth varies: in some places it extends almost to surface while in others it’s covered by 90 metres of leach cap. Its thickness also varies, but it often extends to 250 metres.

The underlying hypogene resource totals 79.1 million tonnes grading 0.26% copper, 0.02% moly and 0.083 gram gold. However, the body remains open for expansion at depth in most areas, as most of the holes drilled at Pyramid to date were only 250 metres long.

The 370 sq. km Pyramid property sits near the southern coast of the Alaska Peninsula, approximately 8 km from tidewater. Full Metal has an exploration agreement and a lease on the lands and mineral rights with Aleut, an Alaska native regional corporation. The company secured surface rights for the property from Shurnagin and TDX, two Alaska native village corporations.

Antofagasta recently fulfilled the first requirement of its Pyramid earn-in agreement, after spending $6 million exploring the property. With a 51% stake confirmed, the major now has the option to earn another 14% by funding a preliminary economic assessment bearing a minimum cost of $4 million. If it does that, Antofagasta could boost its ownership to 80% by advancing the project to feasibility.

The Chilean copper major has conducted a drill program at Pyramid each year for the last three years. In 2010 and 2011 the partners kept their drill pattern constrained to an area measuring 900 by 1,100 metres. In 2012 they ventured beyond that zone to search out more areas of near-surface supergene copper enrichment.

The partners also completed ground magnetic and mapping surveys at the property last year, which identified multiple hydrothermal centres within an oval-shaped zone of phyllic and potassic alteration. The zone measures 2.3 by 1.4 km.

Copper mineralization was discovered at Pyramid in 1974 when Aleut Corp. partnered with two exploration firms to drill 19 shallow holes. Those holes, which Antofagasta and Full Metal used in their recent resource calculation, outlined a 125-million-ton (113-million-tonne) zone of near-surface copper and moly mineralization.

Full Metal’s share price remained unchanged at 3.5¢ on news of the Pyramid resource estimate. The company has a 52-week trading range of 2.5¢ to 18¢ and has 59.3 million shares outstanding. Antofagasta, one of the world’s largest copper producers, saw its share price lose 10 pence on the news to close at £9.31.