Porter Idaho

The 100% owned Porter Idaho high-grade silver asset consists of 46 Crown-granted mineral claims covering the past-producing, underground Prosperity – Porter Idaho – Silverado property located beside the town of Stewart in the Golden Triangle of northwest British Columbia in the Skeena Mining Division. Skeena acquired the asset in September 2016 by acquiring Mount Rainey Silver Inc. by way of a plan of arrangement.

The Porter Idaho project has two known silver-bearing vein systems approximately 2,000 metres apart on opposite sides of Mt. Rainey with a surface portion of the intervening terrain masked by the icefield capping Mt. Rainey. All veins have the same strike, are intimately associated as splays off the well-delineated Silverado Fault and remain open at depth. As the icefield has been rapidly receding during the most recent few decades, it has exposed surface mineralization that may further indicate the apparent structural continuity between the two vein systems.

Porter Idaho contains an historical Indicated Resource of 394,700 tonnes grading 868 g/t silver, 3.37% lead and 1.41% zinc (435,000 tons @ 25.2 oz/ton silver or a contained 11 million ounces silver) and an Inferred Resource of 88,900 tonnes grading 595 g/t silver (97,900 tons @ 17.3 oz/ton silver or a contained 1.7 million ounces silver).

Table 1: Porter Idaho Project Historical Resource Estimate*

@ 170 g/t Ag cut-off

Average Grades

Contained Metal



Ag (g/t)

Pb (%)

Zn (%)


Million Oz


Million lbs


Million lbs

















Since the initial discovery of silver mineralization on Mount Rainey in the early 1900s, various portions of the property have been investigated by more than 6,000 metres of underground workings, including nine adits, several internal shafts and raises, as well as numerous exploration drifts. The majority of the exploration and development work to date, including surface and underground drill programs in the 1980s, was directed at the Prosperity – Porter Idaho silver-bearing, shear zone-hosted epithermal vein structures. Limited production of direct shipping high-grade material, mainly from the Prosperity vein, between 1929 and 1931 amounted to 27,123 tonnes with recovered grades of 2,542 g/t silver (73.8 oz/ton), 0.96 g/t gold, and 4.08% lead (yielding approximately 2.2 million ounces silver).

*Estimates of mineral resources are dated March 10, 2008 and were prepared by independent consulting geologist N.C. Carter, Ph.D., P. Eng. for Raimount Energy Inc. and re-stated for Mount Rainey Silver Inc. on May 15, 2012. The foregoing estimates made use of an extensive database detailing results of both underground sampling programs as well as surface and underground diamond drilling and were prepared pursuant to CIM Standards on Mineral Resources and Reserves. Nevertheless, the reader is cautioned that a Qualified Person on behalf of Skeena has not done sufficient work to verify either the underlying sampling data or the calculation methodology to consider this to be a current resource and as a result, Skeena is treating this mineral resource as an Historical Estimate, as defined in National Instrument 43-101. Skeena has not yet determined what work needs to be completed in order to upgrade or verify the Historical Estimate. 

The scientific and technical information has been reviewed and approved by Skeena’s VP of Exploration, Paul Geddes, P.Geol., a Qualified Person as defined by National Instrument 43-101.