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

Drill results from mineral exploration programs in Canada's Yukon Territory this year are beginning to roll in as numerous companies wind down 2021 field operations in what some describe as one of the busiest mining seasons in years.

Coming on the heels of an eight-year capital market down-cycle, plus a 2020 season burdened with operating restrictions due to the COVID-19 pandemic, the current season is bringing more upbeat challenges to Canada's Far North typically associated with brighter days in the mining sector, such as shortages of drill rigs and skilled workers.

One sector already filing reports of encouraging results from 2021 exploration is base metal and silver projects.

New zone at Macmillan Pass

Fireweed Zinc Ltd., a junior chasing base metal and silver deposits in eastern Yukon, Sept. 16 reported results from a second hole drilled this season in the Boundary West area at its district-scale 940-square-kilometer (363 square miles) Macmillan Pass zinc-lead-silver project.

Three distinct zones of zinc-lead-silver mineralization were intersected in the step-out hole at Boundary West, including a newly discovered zone of high-grade laminated stratiform mineralization similar in style to the Tom and Jason deposits that host the resources at Macmillan Pass. The new stratiform zone graded 23.77% zinc, 3.44% lead, and 75.7 g/t silver over 10.42 meters within a broader zone of 9.91% zinc, 1.64% lead, and 39.6 g/t silver over 32.99 meters.

Massive to semi-massive sulphides under the stratiform interval ran 8.22% zinc, 0.71% lead, and 53.6 g/t silver over 60.68 meters, including a higher-grade massive-sulphide zone of 10.36% zinc, 0.94% lead, and 66.7 g/t silver over 40.08 meters.

A broad zone of vein-hosted mineralization at shallow depths in the hole returned 4.57% zinc, 0.02% lead, and 7.9 g/t silver over 40.24 meters, including a higher-grade zone of 9.99% zinc, 0.06% lead, and 17.4 g/t silver over 13.4 meters.

"(Results from) this hole demonstrates that the new zone has very high grades of zinc, lead, and silver and opens up the rest of the Boundary area to exploration for this style of mineralization," said Fireweed Zinc CEO Brandon Macdonald in the Sept. 16 statement.

"We are also very pleased to see the grades increasing with depth in the massive sulphide mineralization and in the vein-hosted mineralization. This suggests that at Boundary West there is great expansion potential at depth, where even higher grades may be anticipated," he added.

Fireweed Zinc has wrapped up its 2021 drill program with a total of 3,850 meters in 13 holes. The explorer hit mineralization in every hole at the Boundary zone and at Boundary West, including wide massive sulfide zones in three holes and in a hole completed at the Tom East zone.

The company's geologists say mineralization in the Boundary area is analogous to that found at the Red Dog Mine in northeastern Alaska, and Red Dog should be used as a model for future exploration. Red Dog's operator, Teck Resources Ltd., also holds a significant ownership interest in Fireweed Zinc.

"The discovery of yet another high-grade zone this summer further reinforces my belief that Fireweed's Macmillan Pass project is one of the most exciting exploration projects I have ever been involved with," Fireweed Zinc Chairman John Robins added.

At Boundary West, diamond drill hole NB21-002 cut a complete intersection of newly discovered laminated, stratiform zone of zinc-lead-silver mineralization grading 9.91% zinc, 1.64% lead, and 39.6 g/t silver over 32.99 meters, including a very high-grade zone of 23.77% zinc, 3.44% lead, and 75.7 g/t silver over 10.42 meters. This new zone was partially intersected earlier in NB21-001, where the upper portion was truncated by a fault.

In NB21-002, the new zone appears to be comprised of finely laminated sphalerite-galena-pyrite hosted by laminated and silicified mudstone, a style of the mineralization encountered adjacent to, but not directly overlying, the feeder structures at the Tom and Jason zones.

If similar characteristics are encountered at Boundary West, Fireweed Zinc said there could be potential to expand mineralization to depth where even higher grades and massive sulfides may occur.

The junior also said its 2021 program, building on outstanding drill results in 2020, further defined and expanded its exploration targets.

High grade ore at North Rackla

Cantex Mine Development Corp. Sept. 13 reported results from 10 core holes drilled on its 14,077-hectare (34,784 acres) North Rackla claim block in eastern Yukon.

Drilled in the central and northeastern part of the project's Main Zone, nine of the 10 holes encountered exceptionally strong lead-zinc massive sulfide intersections with strong copper mineralization present in seven of the nine holes, Cantex said in a statement.

The mineralized intersections varied in apparent widths up to 11.3 meters and is open to depth and along strike.

Extensive exploration at North Rackla since 2016 has identified numerous targets, including the Main zone where drilling intersected significant high-grade mineralization to a depth of 700 meters with true widths up to 23.7 meters. Drill results from previous seasons have yielded assays averaging 20% lead-zinc and 100 g/t silver.

Cantex said two recent core holes tested an area where surface rock sampling turned up samples with up to 21.7% copper and 60 g/t silver. Massive chalcopyrite (copper‐rich sulfide) was intersected between 20.5 and 20.8 meters in the first hole, and moderate to strong chalcopyrite was intersected between 47 and 55.4 meters in the second hole. However, the actual target depth was about 90 meters to the zone of surficial high-grade copper mineralization identified in rock and talus, so company geologists believe the zone of surficial high‐grade copper has not yet been intersected.

Earlier in 2021, Cantex reported completing seven drill holes to the south and southeast of the Main zone.

Six of the seven holes intersected semi‐massive to massive sulfides consisting of galena and sphalerite (lead and zinc containing minerals, respectively), which in holes YKDD21‐184 and YKDD21‐185 were oxidized. The longest logged mineralized intercept was 24.35 meters in hole YKDD21‐189.

The junior also completed structural mapping on a high‐grade copper showing (anomaly G66) that consistently returned grades of up to 20.8% copper. Cantex also preliminarily mapped anomaly G67, from which rock samples have been collected containing gold grades up to 39.6 g/t.

Mineralization at North Rackla is hosted in Proterozoic aged rocks and has elevated manganese values like the Sedex-style ore recovered at the Sullivan and Mt. Isa mines, according to Cantex.

Since 2016, the explorer has identified and explored other zones and targets at North Rackla, including the South Zone, where a new massive outcropping gossan (oxidized sulfide minerals) zone was discovered 1,000 meters south of the Main zone. The steeply dipping gossan has been traced for 1,200 meters along surface and down 320 meters of elevation, with exposed apparent widths at surface ranging from two to 20 meters. The exposure of the zone correlates well with a linear feature that can be traced for over 1 kilometer of strike length on a recently interpreted magnetic survey. The geophysical character of this zone is comparable to that of the Main zone.

Assays of grab samples taken from this gossan have returned significantly elevated zinc and manganese levels (up to 12.35% zinc and up to 5.82% manganese), which are also key geochemical markers seen at the Main zone.

Porphyry potential west of Dawson

After spending a decade or so focused primarily on exploration of its huge Rackla project in east-central Yukon, ATAC Resources Ltd. looked westward in 2021 and devoted its field season in the Canadian territory to evaluating the early-stage Connaught copper-molybdenum-gold project located 65 kilometers (40 miles) west of Dawson City.

ATAC said the road-accessible Connaught property demonstrates compelling copper-molybdenum-gold porphyry potential and hosts 26 distinct silver-lead-zinc-gold-copper epithermal veins.

The 2021 program focused on evaluating the copper porphyry potential of the 137.3-square-kilometer property.

The junior said highlights of 2021 exploration include assays of rock grab samples from the 100-meter-long trenches it completed at Connaught. The samples returned up to 0.69% copper within a quartz monzonite porphyry and 0.17% copper in an intrusion breccia, while multiple trenches returned broad zones of highly anomalous copper within a quartz monzonite porphyry in areas where copper values are expected to be depleted due to surface leaching, including 331 parts-per-million copper over 93 meters in Trench 21-A, and 548 ppm copper over 69 meters in Trench 21-B.

Nine of the 10 trenches dug this year revealed visual copper mineralization (malachite, azurite, tenorite, and chalcopyrite) within a 400-meter by 500-meter area anomalous for copper- and molybdenum-in-soil, while induced polarization and ground magnetic surveys revealed strong geophysical anomalies that are coincident with zones of elevated copper- and molybdenum-in soil.

Cantex Mine Development Corp.

Drilling has encountered exceptionally strong lead-zinc massive sulfide intersections along with strong copper mineralization at Cantex' North Rackla project in the Yukon.

"We are extremely encouraged with the early exploration results from Connaught, as they strongly support the presence of a copper-molybdenum porphyry," said ATAC Resources President and CEO Graham Downs said in a Sept. 2 statement. "The copper values at surface are very impressive given the extent of surface leaching in an unglaciated environment, and the soil and trenching results compare favorably with surface values at similar projects, such as the Casino deposit."

Casino, located about 160 kilometers (100 miles) south of Connaught, is an advanced stage copper-gold-molybdenum project currently being developed by Western Copper and Gold Corp. It hosts more than 7.6 billion lb of copper and more than 14.5 million oz of gold resources.

Though porphyry potential has long been recognized in the area around Connaught, Graham said systematic exploration for this style of deposit has never been undertaken.

"We look forward to receiving the remaining results so that we can begin planning a maiden drill program targeting the porphyry next season," he added.