Skeena Resources Limited (TSX.V: SKE, OTCQX: SKREF) (“Skeena” or the “Company”) is pleased to announce additional Au-Ag drill results for three drill holes from the ongoing Phase I surface drilling program at the Eskay Creek Project (“Eskay Creek”) located in the Golden Triangle of British Columbia. The multifaceted Phase I program is being performed in the historically drill defined 21A, 21C and 22 Zones. A cross section and tabled data are presented at the end of this release and on the Company’s website.
Eskay Creek Phase I Drilling Highlights
Gold Equivalent (AuEq) was calculated with the formula: Au (g/t) + [Ag (g/t) / 75]. Reported core lengths represent 80-100% of true widths and are supported by well-defined mineralization geometries derived from historical drilling. Length weighted AuEq composites were constrained by geological considerations as well as a calculated 1.0 g/t AuEq assay grade cutoff assuming reasonable prospects for economic extraction via open pit mining methods. Grade capping of individual assays has not been applied to the Au and Ag assays informing the length weighted AuEq composites. Processing recoveries have not been applied to the AuEq calculation and are disclosed at 100% due to a lack of supporting information. Samples below detection limit were nulled to a value of zero.
Phase I Drilling Discussion
The Phase I drilling program on the 21A, 21C and 22 Zones is designed to infill and improve definition in areas with low drill density to a drill spacing sufficient to allow for future economic analyses, and to collect fresh material for an upcoming metallurgical characterization and testing program. As no historical drill core remains for any zones at Eskay Creek, new material must be collected for this purpose. Overall, the metallurgical drilling program is designed to gather unbiased, representative material that is spatially distributed throughout the various zones that will ultimately be used to optimize future economic analyses.
The 21A Zone represents a significant portion of the pit constrained resources hosted at Eskay Creek, containing Indicated Resources of 207,000 oz AuEq grading 5.9 g/t AuEq and Inferred Resources of 418,000 oz AuEq grading 4.6 g/t AuEq.
Designed to infill an area of Inferred Resources, three drillholes were collared on section 10020N, all of which intersected continuous intervals of exhalative mudstone and footwall rhyolite hosted mineralization. Most notably, drillhole SK-18-009 intersected 9.49 g/t Au, 111 g/t Ag (10.97 g/t AuEq) over 42.65 metres including a subinterval within the mudstone averaging 17.35 g/t Au, 147 g/t Ag, (19.31 g/t AuEq) over 19.65 metres. Situated immediately downdip, Phase I drillholes SK-18-010 and SK-18-011 intersected 5.93 g/t Au, 166 g/t Ag (8.14 g/t AuEq) over 36.25 metres and 7.95 g/t Au, 140 g/t Ag (9.82 g/t AuEq) over 33.60 metres respectively. The 21A Zone continues to demonstrate excellent geological and grade continuity and will be further infill drilled during the continuing Phase I program to 20 metre drill spacings to upgrade Inferred Resources to the Indicated category. The 21A Zone is currently drill defined over a large area measuring 420 m along strike and 180 m down dip with true widths ranging from 1 to 80 m in thickness.
21A and 21B Zones – Analogous Mineralization Styles
The 21B Zone is geologically and geochemically equivalent to the 21A Zone and accounted for the bulk of mineralization historically mined at Eskay Creek. The 21B Zone occurs as a tabular, stratiform, fault bounded body characterized by well-bedded, reworked sulfides and sulfosalts interbedded with unmineralized, carbonaceous argillite (mudstone). In addition to the extremely high precious metal grades, Eskay Creek as a whole, particularly the 21A and 21B Zones, is distinguished from conventional VMS deposits by the association with elements of the epithermal suite (Sb-Hg±As). Elevated concentrations of Sb-Hg-As in the 21A and 21B Zones are not evenly distributed throughout the zones but rather occur as isolated clusters due to later stage localized, hydrothermal overprinting.
Although the bulk of the mined material was hosted in the contact mudstone, significant unmined mineralization exists in proximal feeder structures in the footwall rhyolites (21C and Pumphouse Zones). These zones differ geochemically from the 21A and 21B Zones in that they contain low levels of Sb-Hg-As as compared to those hosted in the contact mudstone.
21B Zone Historical Reconciliation
Underground mining at Eskay Creek was performed using the drift and fill mining method with run of mine material either milled at site to generate a concentrate or as direct shipping ore (“DSO”), to smelters. Due to the elevated concentrations of Sb-Hg-As in the 21B Zone, smelter penalties were often prevented via blending with slightly less deleterious material hence diluting the penalty elements while maintaining a profitable head grade.
Based upon historical internal technical reports from the Eskay Creek Mine, the parameters for determining reserves in 2006 were based upon a gold price of US$475.00 per ounce, a silver price of US$8.50 per ounce and a copper price of US$1.50 per pound. The determination of whether material was milled on site versus shipped directly to an offsite smelter was based on mercury concentrations less than 200 ppm and antimony concentrations less than 1% for onsite milling and greater than 200 ppm mercury and greater than 1% antimony for smelter DSO. The same 2006 mill performance report indicates metallurgical recoveries from onsite milling of the 21B Zone at 84% for gold and 96% for silver.
Despite the substantial precious metal grades and base metal credits of the 21A Zone, in the opinion of the Company, the 21A Zone was historically uneconomic due to prevailing low commodity prices combined with smelter penalties and the necessary high cut-off grade used. As well, antimony was treated as a penalty element, but now has the potential to offer significant by-product credits.
About Eskay Creek
In December 2017, Skeena secured an option to acquire 100% interest in the Eskay Creek property. Discovered in the Golden Triangle in 1988, the former Eskay Creek mine produced approximately 3.3 million ounces of gold and 160 million ounces of silver at average grades of 45 g/t gold and 2,224 g/t silver and was once the world’s highest-grade gold mine and fifth-largest silver mine by volume.
A precious and base metal-rich volcanogenic massive sulphide (VMS) deposit, Eskay-style mineralization has been the focus of considerable exploration activity in the Golden Triangle dating back to 1932. Exploration programs in 1988 led to the discovery of the 21A and 21B zones, followed by underground development of the 21B zone starting in 1990 with the official opening of the Eskay Creek mine in 1994. Over the 14-year life of the mine, approximately 2.2 million tonnes of ore were mined with cut-off grades ranging from 12 to 15 g/t AuEq for mill ore and 30 g/t AuEq for direct shipping smelter ore.
Eskay is endowed with excellent infrastructure including all-weather road access and proximity to the new 287-kilovolt Northwest Transmission Line. The Property consists of 8 mineral leases, 2 surface leases and several unpatented mining claims totaling 6,151 hectares.
Eskay is in the traditional territory of the Tahltan Nation. Skeena has a positive working relationship with the Tahltan Central Government (“TCG”) and has signed Exploration and Communication Agreements with the TCG that cover the Company’s other projects in Tahltan territory (see new releases dated September 25, 2017 and January 24, 2017).
Skeena Resources Limited is a junior Canadian mining exploration company focused on developing prospective precious and base metal properties in the Golden Triangle of northwest British Columbia, Canada. The Company’s primary activities are the exploration and development of the past-producing Snip mine and the recently optioned Eskay Creek mine, both acquired from Barrick. In addition, the Company has completed a Preliminary Economic Assessment on the GJ copper-gold porphyry project.