TORONTO (miningweekly.com) – Canadian project developer Seabridge Gold has lifted the compliant inferred resource at its Deep Kerr deposit to above one-billion tonnes, and it was now estimated to contain more than 11.3-million ounces of gold and 11.8-billion pounds of copper.

The explorer on Tuesday published an updated mineral resource estimate for the deposit, which was only a part of the company’s flagship KSM project, in Northwestern British Columbia, adding 3.2-million ounces of gold and 2.1-billion pounds of copper to the 2014 resource estimate, with ores grading 0.35 g/t gold and 0.53% copper in the inferred category.

“The size of Deep Kerr continues to grow with no diminishment of grade. Furthermore, we have not yet found the limits of the immense mineralising system that created Deep Kerr.

"In the three years since its discovery, Deep Kerr has taken its place among the world’s largest gold/copper deposits. The shape of the deposit continues to support cost-effective block-cave underground mining methods and the updated resource estimate has been carefully constrained by this mining method,” stated chairperson and president Rudi Fronk.

Seabridge advised that the geological model for the Kerr deposit, which included Deep Kerr, was a north-south trending, steep westerly dipping, tabular intrusive complex with a horizontal extent of 2 400 m and a vertical extent of at least 2 200 m. The complex included higher-grade east and west limbs that might coalesce near surface.

The west limb was up to 500 m thick and the east limb up to 300 m thick. Last year’s drilling focused on the west limb and successfully confirmed continuity of mineralisation, as predicted by modelling and extending the west limb dip projection over 400 m along a strike length of almost 500 m.

These holes established the western limits of the system as a north-south trending normal fault that placed unaltered fine-grained sedimentary rocks against the mineralised intrusive complex. East of this fault, the mineral system comprised several intrusive bodies, placed into an early-Jurassic sedimentary sequence, with all these rocks containing varying copper and gold grades that merited further exploration.

Further, the Deep Kerr deposit was treated as a potential block cave (bulk underground) mining target. The lateral and vertical continuity of the zone provided a geometric configuration that was likely to be amenable to these mining methods. Seabridge had retained underground mining expert Golder Associates, to undertake bulk underground mining studies for Deep Kerr.