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

TMAC Resources Inc. May 23 announced that commercial production has been achieved at its Doris gold mine and mill at the company's Hope Bay property in Nunavut.

The company said the processing plant at Hope Bay has been operating at greater than 60 percent of its 1,000-metric-ton-per-day capacity since early April and averaged 80 percent of capacity during the first half of May. TMAC said it is making improvements and optimizations that will enable ramp up to steady throughput of 1,000 tpd.

In addition reaching mill capacity, the company is optimizing recoveries, which have yet to reach expected levels.

As improved recoveries are achieved, a transition to higher grade feed from the currently blended, lower grade stockpile ore will be fed to the processing plant.

"Achieving commercial production is a significant achievement of which our entire team is proud. It is a great step toward achieving steady state operations at our Doris Mine and Mill Complex, which is the first step in our plans to funding the development of the Madrid and Boston deposits," said TMAC CEO Catharine Farrow.

A second processing plant is scheduled to be delivered to Hope Bay this summer, which is expected to double the mill throughput to 2,000 metric tons per day when it is operational, expected by early 2018.

In the meantime, TMAC is moving forward with the development and expansion of Doris North BTD, a deeper high-grade zone that is expected to add new reserves to the Doris gold mine.

In 2016, the company reported that underground drilling from Doris had cut high-grade gold in a deeper zone dubbed BTD, short for below the diabase dyke.

Highlights from this drilling targeting BTD include: 17. 7 meters of 35 grams per metric ton gold; 5.3 meters of 50.6 g/t gold; and two meters of 97.7 g/t gold.

The area of BTD currently being targeted is below Doris North, the most northern known extent of the Doris Trend.

The Doris North Hinge zone currently hosts 550,000 metric tons of measured and indicated resources averaging 20.2 g/t (358,000 oz) gold. This deposit is currently only defined above the diabase dyke and extends to a depth of 160 meters.

The Doris North reserves are scheduled to be mined in the first two years of full production at the Doris Mine.

The Doris North BTD zones, which are an extension of Doris North, are subdivided into the Doris North BTD East Limb and Doris North BTD Extension, separated by a northwest-striking fault.

The Doris North BTD Extension is interpreted as the down-dropped continuation of the Doris North zone hinge structure on the north side of the fault and beneath the diabase dyke.

The Doris North BTD East Limb is interpreted as the down-dip continuation of the Doris North East Limb mineralization, south of the fault.

The success of the 2016 exploration program that identified these zones led TMAC to initiate underground development to provide optimized drilling platforms and access to the Doris North BTD East Limb mineralization.

The BTD access ramp had progressed sufficiently to allow exploration diamond drilling to begin testing an area south of the known BTD zones in early March, and is expected to reach the high-grade BTD East Limb and BTD Extension areas in mid-June at which time infill, expansion, and exploration drilling of these zones will begin.

So far, 15 holes have been completed in the area south of the BTD zones and assays have been returned for the first seven. Highlights from this drilling include: 1.2 meter of 40.5 g/t gold in hole TM50049; 1.8 meters of 14.2 g/t gold in TM50050; and 3.1 meters of 7.0 g/t gold in TM50051.

"As a result of today's encouraging drill intersections, we have been able to refine our understanding of the major ore-hosting structures at depth at Doris North, and to have the confidence to add a second drill to the underground drill program as drill bays become available," said Farrow.

Drilling will continue to target this area south of the BTD Extension zone until the BTD exploration drift and drill bays are complete, expected by mid-June, at which point the two diamond drills will transition to infill, expansion, and exploration drilling at the known high-grade portions of the BTD Extension identified last year.

"Consistent with TMAC's philosophy of optimizing infrastructure, the current Doris North BTD development ramp will be multifunctional, providing physical access to the Doris North BTD East Limb, more efficient drilling platforms proximal to both the BTD East Limb and the BTD Extension, and drill platforms to facilitate targeting of additional exploration areas below the diabase dyke. Ultimately this work is expected to provide TMAC with the opportunity to significantly extend mine life at Doris," the TMAC CEO added.

-SHANE LASLEY