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1.7M oz Carlin-type gold at ATAC's Osiris


Last updated 6/29/2018 at 4:22am

ATAC Resources Osiris gold deposit, resource Rackla Barrick Orion

Shane Lasley

A helicopter flies over the site where ATAC Resources discovered Carlin-type gold mineralization at the Osiris project on its expansive Rackla Gold property in the Yukon.

ATAC Resources Ltd. June 18 reported a 1.69-million-ounce maiden gold resource for Osiris, one of three projects that make up the 1,700-square-kilometer (656 square miles) Rackla Gold property in the Yukon.

Osiris is where ATAC first discovered Carlin-type gold, which is found in sediment hosted deposits where very fine-grained gold is typically associated with pyrite or arsenopyrite. This type of gold mineralization gets its name from the Carlin Mine in Nevada, where it was first recognized in the 1960s.

The Carlin-type gold at Osiris is found in 12.4 million metric tons of inferred resource averaging 4.23 grams per metric ton gold and includes 8 million metric tons of pit-constrained, considered mineable from the surface, inferred resource averaging 4.08 g/t (1.06 million oz) gold.

The balance of the resource – 4.34 million metric tons averaging 4.52 g/t (630,000 oz) gold – is considered better suited for underground mining.

"Defining a maiden resource with over one million pit-constrained ounces is a major development for the company and highlights the emerging high-grade open-pit potential," said ATAC President and CEO Graham Downs. "With only 78,614 meters used to define the resource we achieved an excellent discovery rate of over 21 ounces of gold for every meter drilled."

Most of the gold outlined so far at Osiris is found in the Conrad zone, which hosts 835,000 oz of the pit-constrained gold, in 6.49 million metric tons averaging 4 g/t gold, and 455,000 oz of the underground gold, in 3.17 million metric tons averaging 4.46 g/t gold.

The rest of the resource is found in the Osiris, Sunrise and Ibis zones.

"With the announcement of this maiden resource, it appears that the early stage Osiris project may have the potential to follow a 'life-cycle' path similar to many of the large producing Carlin-deposit mines in Nevada. Many of these mines started life with an initial open pit followed by underground mining," said Ed Cope, a technical advisor to ATAC. "In many cases, the initial discoveries expanded dramatically with additional exploration and were commonly followed by the discovery of more, and often larger, deposits resulting in the great mining camps of the Nevada trends. Classic examples are represented by the original Carlin Mine, Goldstrike, Cortez and Getchell-Turquoise Ridge, to name a few."

Cope, who retired as vice president, North America for Barrick Gold in 2016, knows a bit about these classic examples of Carlin-type deposits. During his 21 years at Barrick, Cope helped build and guide the technical teams responsible for defining some of the major gold miner's largest gold deposits within the Carlin and Cortez trends in Nevada.

Expanding Osiris

ATAC is looking to expand the maiden resource at Osiris with a 10,000-meter drill program slated for this year.

"Expansion drilling is in full-swing with two drills focused on step-out drilling at the eastern end of the Conrad zone," said Downs.

This Conrad expansion drilling is starting out with holes near OS-17-238, a 2017 hole that cut 12.5 meters of 20.78 g/t gold.

Drilling at Sunrise is scheduled to begin soon.

So far, 309,000 metric tons of open-pit inferred resource averaging 4.23 g/t (42,000 oz) gold; and 531,000 metric tons of underground inferred resource averaging 5.53 g/t (95,000 oz) gold has been identified at Sunrise.

Located on a ridge-top, Sunrise has only been drilled for about 300 meters along strike and to a depth of 350 meters. This year's drilling there will step out from OS-17-249, a hole drilled last year that cut 15.24 meters of 13.52 g/t gold and 10.42 meters of 7.97 g/t gold.

ATAC says there is excellent potential for new discoveries across the 302-square-kilometer (117 square miles) Osiris Project.

Additional mapping, prospecting and rotary air-blast drilling will be conducted throughout the Osiris project to test for extensions or new areas of mineralization.

Drills turning at Orion

As ATAC looks to expand the gold resource at Osiris, Barrick is carrying out a roughly 10,000-meter drill program at Orion, a 780-square-kilometer (301 square miles) project immediately west of Osiris and in the middle of ATAC's roughly 185-kilometer- (115 miles) long Rackla land package.

"A total of five drills are now operating between Barrick's Orion project earn-in and ATAC's Osiris project, representing our largest drill campaign since 2012," said Downs.

Like Osiris, the Orion project is rich in Carlin-type gold mineralization.

Barrick's initial program, carried out last year, demonstrated that favorable environments for the development of gold mineralization at Orion are more extensive than previously understood.

The 2018 drilling is expected to primarily focus on the 6,000-meter-long Anubis Fault corridor, where ATAC cut 8.5 meters of 19.85 grams per metric ton gold in the Anubis zone and 61.3 meters of 2.75 g/t gold in the Orion zone prior to optioning the property to Barrick.

Nine other prospecting discoveries within the Anubis Cluster (Ana, Corona, Columba, Dale, Dorado, Draco, Hydra, Lyra and Zodiac) have received only cursory follow-up since their discovery in 2013.

"Our technical team will work alongside Barrick to unlock the discovery potential we see emerging at the Orion project," Downs said earlier this year.



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