The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
North of 60 Mining News - July 5, 2024
Since feeding the first material into the mill at Premier toward the end of March, Ascot has been working through the challenges associated with commissioning a gold mining operation.
Underground mining has reached high-grade ore stoping areas at Big Missouri.
Daily and seven-day average of mill throughput at Premier during the second quarter.
True to the very purpose of starting with a commissioning period prior to commercial mining operations, Ascot Resources Ltd. has run into challenges as it ramps up to full-scale production at its Premier gold-silver mine within Nisga'a First Nation territory about 15 miles (25 kilometers) north of Stewart, British Columbia.
"While various challenges were encountered within the mill startup, many corrective measures and changes have been made, resulting in an upward trajectory in processing reliability, throughput, and the ensuing gold pours," said Ascot Resource President and CEO Derek White.
Ascot began feeding low-grade ore into the Premier mill at the end of March and poured its first gold at the high-grade underground mining operation on April 22. As of the end of June, the company had poured 839 ounces of gold and 1,288 oz of silver.
Overall, the mill processed 85,436 metric tons of ore during the second quarter, which contained an estimated 5,713 oz of gold. Of this, Ascot estimates that 3,178 oz remains in the mill circuit.
"Ascot progressed through many important milestones in the second quarter, including the start of processing commissioning ore in the mill, the first gold pour from the gravity circuit, and subsequent pours from the carbon-in-leach circuit as a part of the commissioning process," White added.
The Premier mill includes conventional crushing and grinding, followed by a gravity circuit and then a standard carbon-in-leach process to recover gold and silver.
While Ascot faced commissioning challenges throughout the process plant, the most persistent were related to the carbon-in-leach circuit gold recovery circuit.
The company says these challenges have mostly been surmounted with process changes made in June, and it is starting to see the benefits of those changes in the amount of gold contained in each pour.
Daily and seven-day average of mill throughput at Premier during the second quarter.
The Premier mill reached its nameplate capacity of 2,500 metric tons per day for the first time on June 21. As of the end of the month, the seven-day average mill throughput was around 1,400 mt/d.
Ascot estimates that the material fed through the mill so far has averaged around 2 grams of gold per metric ton. Grades are expected to increase significantly as the mill transitions from commissioning to commercial ore production.
At the start of operations, Premier hosted 3.63 million metric tons of probable reserves averaging 5.45 grams per metric ton (637,000 oz) gold and 19.1 g/t (2.23 million oz) silver within the Silver Coin, Big Missouri, and Premier deposits; plus 2.55 million metric tons of proven and probable reserves averaging 6.52 g/t (534,000 oz) gold and 20.6 g/t (1.69 million oz) silver at Red Mountain, which is on a separate property about 20 kilometers (12 miles) to the southeast.
The first commercial ore to be fed into the Premier Mill is coming from Big Missouri, a high-grade deposit about 3.7 miles (six kilometers) north of the Premier mill, which hosts 809,000 metric tons of the overall probable reserves averaging 7.15 g/t (186,000 oz) gold and 12.2 g/t (317,000 oz) silver.
Ascot says the pace of underground mine development at Big Missouri increased during the second quarter.
Underground mining has reached high-grade ore stoping areas at Big Missouri.
Procon Mining & Tunnelling Ltd., which is carrying out the underground mining for Ascot, advanced 1,764 meters of underground development at Big Missouri during the second quarter, including 525 meters of development ore and 1,239 meters of waste.
As a result, 47,158 metric tons of ore were mined from Big Missouri, primarily from development headings. Upon completion of a secondary egress in June, mining is targeting higher-grade stope blocks, which have been averaging approximately 800 metric tons per day at the end of June. Ascot expects this trend to continue in July.
As of June 30, approximately 11,614 metric tons of ore were stockpiled, which is supplemented by ore coming directly from Big Missouri.
At the same time, Procon is accelerating underground mine development at Premier-Northern Light, a deposit next to the mill. Advancing at a rate of roughly six meters per day during June, the mining contractor is expected to reach the first development ore at Premier-Northern Light in September, with stope production slated to start in October.
With the mill beginning to run at a steady pace and underground development reaching ore, Ascot anticipates the rate of gold coming out of the mill to increase over the coming days and weeks.
"With stoping activity in higher-grade areas having started at the Big Missouri deposit, we anticipate a noticeable increase in gold pours in the very near term," said White.
Once up and running at its full 2,500-metric-ton-per-day capacity, Premier is expected to produce roughly 1.1 million oz of gold and 3 million oz of silver over the initial eight years of mining.
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.
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