The mining newspaper for Alaska and Canada's North

Game-changing Johnson Tract discovery

HighGold's first DC hole hits 6.4 meters of 577.9 g/t gold Mining Explorers 2021 - January 27, 2022

HighGold Mining Inc. is rapidly unlocking the potential of Johnson Tract, a high-grade polymetallic gold project that exemplifies the exceptional mineral exploration opportunities Alaska has to offer.

A parcel of land privately-owned by Cook Inlet Regional Inc., an Alaska Native regional corporation more commonly known as CIRI, Johnson Tract is a moderately advanced gold project that has flown under the radar for more than two decades.

By the 1990s, exploration by Anaconda Mining and Westmin Resources Ltd. had outlined an estimated 1.04 million metric tons of resource averaging 10.05 grams per metric ton gold, 7.63 g/t silver, 8.32% zinc, and 1.13% lead had been outlined in what is now known as the JT deposit on the 20,942-acre Johnson Tract in Southcentral Alaska.

Despite these high grades and the evident potential to grow this resource, weak precious metals prices at the end of the 20th century put a halt to Westmin's plans to develop a mine at Johnson Tract, and the enticing project faded into obscurity.

Seeking to further unveil the gold potential on its land, CIRI went on a search for a mineral exploration company with a particular skillset – the geological prowess to unlock the value at Johnson Tract coupled with an excellent environmental, social, and governance reputation – a search that led to HighGold.

"They approached us to explore and develop the assets on their lands," said HighGold Mining President and CEO Darwin Green.

In the three years since leasing Johnson Tract from CIRI, HighGold has validated the high-grade resource and expansion potential at the JT deposit and has begun to unlock the value of multiple earlier staged targets along a highly mineralized trend that extends roughly five miles (nine kilometers) northeast from JT.

As exciting as the confirmation and expansion of the JT deposit has been, a bonanza grade gold-silver intercept in HighGold's first hole at Difficult Creek shows the true potential of this Southcentral Alaska property that has been hiding in plain sight for more than two decades.

Setting the stage for 2021

With an already well-advanced gold-rich polymetallic project located on highly prospective lands owned by an Alaska Native corporation, Johnson Tract offers a uniquely Alaskan opportunity for HighGold, which was spun out of Constantine Metal Resources Ltd. in 2019 to advance this and other gold projects.

The company started its exploration of Johnson Tract by upgrading and expanding the JT deposit.

Based on nine holes completed by HighGold and the historical drilling, an industry-compliant 2.14 million metric tons of indicated resource averaging 6.07 g/t (417,000 oz) gold, 5.8 g/t (397,000 oz) silver, 5.85% (275.3 million pounds) zinc, 0.71% (37.6 million lb) lead, and 0.57% (26.8 million lb) copper; plus 581,000 metric tons of inferred resource averaging 2.05 g/t (38,000 oz) gold, 6.67% (85.5 million lb) zinc, 0.33% (4.2 million lb) lead, and 0.54% (6.9 million lb) copper was established for JT.

With the resource confirmed, the company focused its 2020 drilling primarily on resource expansion targets at and around the JT deposit.

Highlights from this 16,418-meter program include:

74.1 meters averaging 17.89 g/t gold, 7.1 g/t silver, 0.48% copper, 7.28% zinc, and 1.31% lead in hole JT20-092.

75.1 meters averaging 10.01 g/t gold, 6 g/t silver, 0.57% copper, 9.36% zinc, and 1.11% lead in JT20-093.

20.1 meters averaging 11.5 g/t gold, 4 g/t silver, 0.5% copper, and 3.1% zinc in JT20-096.

22.8 meters averaging 3.2 g/t gold, 4 g/t silver, 0.4% copper, and 6% zinc in JT20-106.

58.6 meters averaging 1% copper and 21 g/t silver, including 12 meters averaging 2.8% copper and 51 g/t silver in JT20-110.

18.3 meters averaging 5.9% zinc, 64 g/t silver, and 0.1% copper in JT20-121.

While the drills were turning, a team of HighGold geologists carried out a large-scale regional reconnaissance exploration across the roughly 21,000-acre property that identified exciting targets for the 2021 drill season.

Based on the results of the 2020 program, the HighGold team put together a nearly 16,198-meter drill program for 2021 that continued resource expansion at JT and tested several of the other prospects this metal-rich project has to offer.

"During the off-season, our geological team developed and refined a large number of high-quality drill targets that we are eager to pursue," Green said at the launch of the 2021 program. "The upsized program allows us to more aggressively test these target areas, particularly amongst the regional prospects, most of which are being drill-tested for the very first time."

Expanding JT Deposit

Roughly half of the 2021 Johnson Tract drill program continued to test targets at and around JT deposit.

The JT deposit area targets include:

JT Deposit Expansion – Step-out holes along strike and down-plunge from the current resource.

Revised Fault Offset Target – Which is testing a new interpretation of the JT deposit fault displacement.

GAP Target – This includes widely-spaced fans of holes to test a poorly drilled area immediately along strike to the northeast of JT deposit.

Footwall Copper Zone - Step-outs at depth from the copper-rich zone discovered in 2019, where hole JT19-089 cut 20.7 meters averaging 2.4% copper, 4.9% zinc, and 32 g/t silver.

2020 VMS Zone – Follow-up on the 7.8 meters at 6.1% zinc, 1.6% lead, 0.2% copper, 0.7 g/t gold, and 36 g/t silver encountered in JT20-114, a hole drilled last year.

Building on the success of the 2020 drill program, the first hole of the 2021 program, JT21-123, cut 4.3 meters averaging 13.1 g/t gold, 200 g/t silver, 4.92% zinc, 2.04% lead, and 0.35% copper.

The mineralization encountered in this hole is hosted within a fine-grained mudstone unit that is similar to the VMS-style of mineralization cut by hole JT20-114.

"Our first drill hole of the season has intersected strong precious and base metal mineralization in a large step-out from last year's drilling, expanding the total strike length of JT deposit mineralization by 15-20% to 600 meters," said Green. "In addition to the excellent gold grades, the intersection includes some of the highest silver grades documented to date at the JT Deposit and is developed within a mudstone host – features often found in gold-rich VMS deposits."

HighGold says the mineralization tapped in JT21-123 highlights the overall exploration potential at Johnson Tract.

Another hole targeting the lower reaches of the deposit, JT21-125, cut 56.6 meters averaging 18.69 g/t gold, 2.43% zinc, and 0.47% copper from a depth of 236.7 meters.

This intercept included two very high-grade subsections – five meters averaging 64.7 g/t gold, 1.49% zinc, and 0.53% copper from 273.4 meters; and 4.9 meters averaging 114.37 g/t gold, 3.51% zinc, and 0.33% copper from 288.4 meters.

Samples of the core from this hole will be used for metallurgical work to confirm results reported in the 1990s and identify possible opportunities for improvement.

Game-changing DC hole

The 2021 success at JT Deposit was eclipsed by the spectacular gold and silver grades tapped in the first hole of the regional exploration drilling carried out across the wider Johnson Tract property last year.

While most of the historic and all of HighGold's drilling up to the 2021 season targeted JT, it has long been known that a series of regional prospects that spans a 7.5-mile-long mineralized trend across the property.

One of the better-known and most intriguing areas is Difficult Creek, or DC prospect, which lies about 2.5 miles northeast of the JT deposit.

DC prospect was tested by three holes in the 1980s. The first two of these holes cut:

DC83-001 cut 7.8 meters averaging 4.3 g/t gold, 78 g/t silver, and 2.7% zinc.

DC83-002 cut 36.3 meters averaging 3.57 g/t gold, 15.5 g/t silver, 1.8 % zinc.

As intriguing as these results are, they do not compare to the first hole drilled by HighGold in this area.

DC21-010, cut 6.4 meters averaging 577.9 g/t (18.58 oz/t) gold, 2,023 g/t (65 oz/t) silver, 2.15% zinc, and 0.3% copper down dip of hole DC83-001. This incredible intercept included a 1.26-meter subsection averaging 2,860 g/t (91.95 oz/t) gold, 9,990 g/t (321.2 oz/t) silver, 5.04% zinc, and 0.88% copper.

"Without a doubt, this is a game-changing drill hole that firmly establishes the DC prospect as a second center of high-grade mineralization and validates our conviction in the multi-deposit potential at Johnson Tract," said Green. "The bonanza grade intersection in hole DC21-010 represents the highest grade drilled to date on the JT project, which is a significant achievement given the number of outstanding drill intersections generated previously in the main JT deposit area."

The DC prospect is characterized by a series of large gossan alteration zones – Milkbone, Middle DC, and Upper DC Vein Field – similar in style to the JT deposit that collectively extends over a 1,500- by 3,000-meter area.

HighGold says the widespread extent of mineralization exposed by erosion across this large area supports the potential for a large and partially blind mineralized system linking the various DC prospect zones together.

To test this potential, HighGold drilled 17 holes in the DC prospect area. This includes seven in the Middle DC prospect area, where the bonanza grade intercept was drilled.

The 2021 regional drill program also tested Kona, which lies about 2,500 meters west of DC.

HighGold is incorporating the results from the more than 30,000 meters of drilling completed during the 2020 and 2021 exploration seasons into an updated mineral resource estimate slated for completion early this year.

Author Bio

Shane Lasley, Publisher

Author photo

Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.


Reader Comments(0)

Rendered 05/19/2024 17:20