The Meadowbank gold mine achieved commercial production in March 2010, and produced its three millionth ounce of gold in 2018. It has 98,000 ounces of gold in proven and probable reserves (1.6 million tonnes at 1.89 g/t) as of December 31, 2018. Meadowbank mine is expected to produce 65,000 ounces of gold in 2019, which is anticipated to be the last year of the mine production.
The extension of the mine production at Meadowbank mine to mid-2019 will bridge the gap between the expected cessation of mining activities at Meadowbank in mid-2019 and the expected start of operations at Amaruq in Q3 2019. The additional production has come from an extension of the mine plan at the Vault and Phaser pits in 2018 and the Portage pit in 2018 and 2019, supplemented from stockpiles in 2018 and 2019.
Amaruq ore will be hauled by a long haul off-road truck fleet to the mill at the Meadowbank facilities for processing. The mining, processing and infrastructure at the Meadowbank mine site and the mining and infrastructure at the Amaruq site are together referred to as the Meadowbank Complex.
Geology
The Meadowbank property is underlain by Archean-age volcanic and sedimentary rocks. The Goose and Portage deposits are hosted by magnetite-rich iron formation, while intermediate volcanic rocks host most of the mineralization at the Vault deposit farther north. Both the rock units and the gold deposits are tightly folded and structurally complex, sandwiched between granite plutons.
Mineralization
Gold deposits are found along two main structural features that cross the property – the Meadowbank Trend and the Pipedream Lake (Northeast) Trend. The Meadowbank Trend hosts the Goose, Portage and Vault deposits, which are the sites of mining. These shallow deposits lie within 7 km of each other. In all deposits, gold mineralization is commonly associated with intense quartz flooding, and the presence of sulphide minerals (pyrite and/or pyrrhotite).
Mining
Meadowbank has conducted surface mining from a series of three pits all within 7 km of the processing plant. Water retention dykes have been built to allow for mining beneath shallow lakes, using a unique in-water dyke construction method. Dewatering of Vault Lake, for example, has allowed the Vault pit to be mined since April 2014. The mine works year-round, using conventional drilling, blasting, truck and shovel methods. Waste rock is used for construction, or dumped in waste storage sites or previously mined-out areas. To minimize acid generation, the sulphide-bearing waste rock is encapsulated in permafrost and capped with an insulating layer of neutralizing rock.
Processing
The 11,000-tonne/day gold processing plant uses conventional technology adjusted to the Arctic climate. After two stages of crushing and grinding, any “free gold” is removed by a gravity circuit. The remainder is leached using cyanide, with the gold captured using carbon-in-pulp technology and electrowinning cells. Gold-plated cathodes and gravity concentrate are smelted in an induction furnace and poured as doré bars. The plant includes both a cyanide recycling thickener and an air-sulphur dioxide cyanide destruction circuit to ensure that no cyanide escapes to the environment. All water from the tailings pond is pumped back to the plant for reuse, making this a zero-discharge system. The plant is undergoing minor modifications to treat the Amaruq ore, specifically the addition of a continuous gravity and regrind circuit, and is expected to operate at 9,000 to 10,000 tonnes/day processing Amaruq ore. Gold recovery is expected to be 93% for the Whale Tail ore and 95% for IVR ore based on testing.
Exploration
Exploration is being conducted at the Amaruq satellite deposit, located 50 km northwest of Meadowbank.