North of 60 Mining News - The mining newspaper for Alaska and Canada's North

Aston Bay Holdings Ltd. Oct. 23 reported that results from a nine-hole drill program carried out this summer has helped to refine targets for both the copper and zinc mineralization at its Aston Bay property on Somerset Island, Nunavut.

The 2018 drill program tested the two main targets identified so far at Aston Bay – Storm Copper and Seal Zinc, outcropping high-grade copper and zinc deposits.

Aston Bay believes the fluids that deposited copper and zinc at the two surface deposits mineralized other horizons at depth, leaving the real prizes on its holdings yet to be discovered.

To help identify areas of potential hidden mineralization, Aston Bay had a high-resolution gravity gradiometry survey – a geophysical technique that measures minute differences in the earth's density to yield information on underground geologic structures – flown across the more than 1-million-acre Aston Bay property in 2017.

The company said results from this geophysical work, along with previous versatile time domain electromagnetic (VTEM) geophysical surveys are helping to delineate copper mineralization at Storm, where the company completed seven holes this year.

Hole AB18-09 targeted a 200- by 200-meter VTEM anomaly coincident with the western flank of a gravity anomaly. A historical hole, ST97-15, drilled northwards to intersect local copper mineralization cut three meters grading 1.5 percent copper on what Aston Bay's modelling interpreted as the flank of the VTEM anomaly. Drilled southward, AB18-09 cut significant copper from 39 to 83 meters downhole.

Significant results within the 44-meter mineralized zone include: 1.5 meters of 4.39 percent copper and 9.76 grams per metric ton silver from 39 meters; and 20.5 meters of 0.56 percent copper from 62.5 meters.

Aston Bay said these intercepts demonstrate the effectiveness of VTEM, in conjunction with modelled gravity gradiometry, in detecting shallow copper sulfides. The remaining holes at Storm intersected local pyrite mineralization.

"Results at Storm will provide impetus for continued improvement of geophysical modeling, and refinement of drill targets for the 2019 season," said Aston Bay Holdings Chief Geologist David Broughton.

Roughly 20 kilometers (12.5 miles) northwest of Storm, the high-grade Seal zinc deposit lies at the base of a small peninsula about 200 meters from tidewater.

Late in 2017, Aston Bay Holdings published an updated resource estimate for Seal based on drilling carried out by Cominco in 1995-96 and Noranda in 2001.

At a 4 percent cut-off grade, Seal hosts 1 million metric tons of inferred resource averaging 10.24 percent (227 million pounds) zinc and 46.5 grams per metric ton (1.5 million ounces) silver.

The 2017 geophysical survey turned up several gravity anomalies occurring along trend to the north and south of the Seal deposit. Two of these anomalies in the Seal North area have coincident historical zinc-in-soil anomalies and are targets for ground follow-up and potential drilling.

Due to challenging weather conditions, along with an initial focus on Storm, only two holes were completed this year at Seal.

Despite the limited program, Aston Bay said the drilling discovered an interpreted extension of the Seal mineralized system roughly 1,200 meters south along strike, in the northernmost part of the Seal South area and adjacent to tidewater.

Drill hole AB18-06B targeted the extreme northern end of an 800-meter-long positive gravity gradiometry anomaly coincident with local sphalerite-pyrite mineralization.

From a depth of 125 meters, AB18-06B cut six meters of 0.67 percent zinc.

The property is underlain by Paleozoic carbonate rocks with demonstrated affinities to the nearby past-producing Polaris zinc mine about 170 kilometers (105 miles) to the northwest.

A zinc mineralized pseudobreccia – limestone with a coarsely crystalline, apparently fragmented texture resembling that of a breccia – encountered in AB180-06B is considered analogous to pseudobreccia present at the Polaris deposit. Aston Bay interprets the discovery of this pseudobreccia at Seal South as a favorable indicator of hydrothermal alteration and the potential for additional stratiform zinc mineralization in vicinity of Seal.

"Aston Bay is very encouraged by the discovery of zinc mineralization coincident with Polaris-type pseudobreccia spatially associated with the S12 gravity anomaly at Seal South, at this early stage of testing the multiple anomalies in the vicinity of the Seal deposit," said Broughton.

The last hole of this year's program at Seal, AB18-08, cut 1 meter of 0.16 percent zinc about 100 meters southeast of AB18-06B. Core recoveries in the zone were poor, only 38 percent in the specified interval.

"These results demonstrate that we now better recognize the signature of both copper and zinc mineralization in our data," said Aston Bay CEO Thomas Ullrich. "We are eager to apply these insights to drilling throughout this large and prospective property."

–SHANE LASLEY