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

Dolly Varden Silver Corp. said the work it carried out in 2019 has positioned its namesake high-grade silver project in British Columbia for additional growth in 2020.

Located at the southern tip of B.C.'s Golden Triangle, the Dolly Varden property covers historic high-grade silver mines that date back to the early 20th century. Much of the company's exploration work has focused on exploring in and around four of these producing mines – Torbrit, Dolly Varden, Wolf and North Star.

Four deposits associated with these past producing mines host 3.42 million metric tons of indicated resource averaging 299.8 grams per metric ton (32.93 million oz) silver; plus 1.29 million metric tons of inferred resource averaging 277 g/t (11.48 million oz) silver, according to an updated calculation completed in May.

The bulk of the resources are found at Torbrit, which hosts 2.62 million metric tons of the indicated resource averaging 297 g/t (25.03 million oz) silver; and 1.19 million metric tons of the inferred resource averaging 278 g/t (10.59 million oz) silver.

While smaller, the Dolly Varden deposit hosts some of the highest grades on the property – 156,000 metric tons of indicated resource averaging 414 g/t (2.08 million oz) silver; and 86,000 metric tons of inferred resource averaging 272 g/t (754,000 oz) silver.

The 11,836 meters of drilling completed this year in 44 holes, however, investigated the property's wider potential. Targeting for this drilling was based on a recent reinterpretation of the geological model for the known deposits, improving confidence and providing a more robust framework for targeting future exploration on the high-grade silver property.

This led to the discovery of Chance, a target about 4,000 meters north of the Torbrit deposit that was known from shallow surface diamond drilling in the 1960s.

The Chance discovery hole, DV19-165, cut 26.5 meters averaging 385.4 g/t silver, along with small amounts of zinc and lead, including five meters of 1,606.5 g/t silver.

DV19-173, another hole drilled at Chance, cut 15.2 meters averaging 488.3 g/t silver, including 5.6 meters of 1,043.8 g/t silver.

DV19-169, which intersected what appears to be a splay of the Chance vein, cut 8.7 meters of 265.2 g/t silver in the north splay and 12.5 meters of 340.7 g/t silver, including three meters of 700 g/t in the main splay of the vein.

In addition to Chance, the reconnaissance drilling carried out this year turned up interesting results at four other exploration targets on the property – Silver Horde, Mackay, Beginner's Luck and Kitsol South.

DV19-188, drilled at Silver Horde cut 3.65 meters averaging 139.1 g/t silver.

DV19-177, drilled at Mackay, cut 1.75 meters averaging 126.4 g/t silver, 2.27 percent lead and 0.04 percent zinc.

DV19-203, drilled at Beginner's Luck, cut 4.4 meters averaging 99.2 g/t silver, along with small amounts of zinc and lead.

DV19-205, drilled at Kitsol South, cut 3.3 meters averaging 148.9 g/t silver, along with small amounts of zinc and lead.

In addition to exploring the wider potential of the property, Dolly Varden carried out metallurgical testing for recovering the silver, zinc and lead in the two primary deposits – Torbrit and Dolly Varden.

The company says this work shows that the production of separate lead and zinc flotation concentrates from a composite of representative samples from Torbit to be relatively straightforward. The majority of the silver reports to a high-grade lead concentrate averaging 58 percent lead, 25,000 g/t silver and 3 percent zinc. The zinc concentrates average 36 percent zinc and 2,979 g/t silver. The floatation recovers about 64 percent of the silver, 78 percent of the lead and about 64 percent of the zinc. Using leaching to recover additional silver from the tails of the floatation circuit increased silver recoveries for Torbrit to 88 percent.

For the Dolly Varden deposit composite, the higher zinc content relative to lead made the production of a high-grade lead concentrate more challenging. A lead concentrate was produced containing 21 percent lead, 22,000 g/t silver and 23 percent zinc. No separate zinc concentrate was created in this test. The floatation circuit recovered 59 percent of the lead and 65 percent of the silver. Leaching of the tails increased the silver recovery for Dolly Varden to 84 percent.

The Dolly Varden property is well positioned to deliver the lead and zinc concentrates to market.

A 25-kilometer (16 miles) access road that follows a railway bed originally constructed for the historic Dolly Varden Mines Railway, links the property to tidewater at the head of the deep-water Alice Arm fjord.

Dolly Varden said numerous repairs to creek-crossing bridges have been performed and the road is accessible to the heart of the mineral claims.

The base camp for the Dolly Varden project is in the nearby village of Alice Arm, where the company has a drill core logging facility, core storage, geology office, cook house, machine shop and camp.

The Dolly Varden project lies within the traditional territories of one First Nation and that nation has an established treaty with the federal and provincial governments.

An initiative to demonstrate the cooperation between the mining industry, First Nations and the Province for development in the Golden Triangle was established in 2017 as the British Columbia Regional Mining Alliance (BCRMA).

Dolly Varden Silver Corp is a founding member of the BCRMA, along with the Nisga'a Lisims Government, the representative body of the Nisga'a First Nation; Tahltan Central Government, which represents the Tahltan First Nation; province of British Columbia; Association for Mineral Exploration; and three other active junior mining exploration companies.

Dolly Varden also focuses on local hire, with members of the Nisga'a making up roughly one-third of the workforce on the Dolly Varden project.

"Our team has advanced the Dolly Varden project substantially over the past season, including new discoveries from diamond drilling, an updated mineral resource estimate, and completion of successful metallurgical tests. As well, on the ground we have improved the logistical advantages and strengthened our relationships with the community," said Dolly Varden Silver President and CEO Gary Cope. "The Dolly Varden project is well positioned for growth in the coming year."

–SHANE LASLEY