The Meadowbank Complex refers to the mining, processing and infrastructure at the Meadowbank mine site combined with the mining and infrastructure at the nearby Amaruq site. The remote Meadowbank mine camp, with recreational and fitness facilities, can host more than 500 employees at a time. The Amaruq camp can host an additional 350 employees.
The Meadowbank gold mine achieved commercial production in March 2010 and produced its three millionth ounce of gold in 2018 and 2019 was the final year of production at the Meadowbank mine.
The 117,820-hectare Amaruq property is located approximately 50 km northwest of the Meadowbank mine site. Discovered in 2013, Amaruq hosts the Whale Tail gold deposit as well as the V and Mammoth zones and several other targets. At December 31, 2019, the Amaruq satellite deposit at Meadowbank was estimated to contain open pit proven and probable mineral reserves of 2.7 million ounces of gold (22.8 million tonnes grading 3.74 g/t), underground probable mineral reserves of 577,000 ounces of gold (3.3 million tonnes grading 5.43 g/t), as well as substantial open pit and underground indicated and inferred mineral resources.
The Amaruq mining operation uses the existing infrastructure at the Meadowbank mine (mining equipment, mill, tailings facilities, camp and airstrip). Additional infrastructure has been built at the Amaruq site (truck shop/warehouse, fuel storage and a larger camp facility). Amaruq ore is transported using long haul off-road type trucks to the mill at the Meadowbank facilities for processing. The Company declared commercial production at the Whale Tail pit at Amaruq on September 30, 2019.
The life of mine plan for the Whale Tail pit calls for the production of approximately 2.5 million ounces of gold between 2019 and 2026.
Permitting for the Amaruq Phase 2 expansion, including an open pit at the V Zone and underground operations, is ongoing. If this expansion is approved, it would increase production rates and further extend the mine life for the Meadowbank Complex.
Geology
The Meadowbank and Amaruq properties are underlain by Archean-age volcanic and sedimentary rocks of the Woodburn Lake Group. This is within the Rae domain of the Western Churchill geological province of the Canadian Shield. These rocks were possibly deposited in a continental rift setting and consist of mafic to ultramafic volcanic rocks interlayered with carbon-rich sedimentary rocks. The rock sequence has since been intruded by granitoid rocks and lamprophyres, and has been affected by multiple phases of ductile deformation along with metamorphism to greenschist facies and locally to the upper greenschist facies.
Mineralization
Gold deposits at the Meadowbank property 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 were the sites of mining. 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 granitic plutons. 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).
At the Amaruq property, three significant zones of gold-bearing quartz-pyrrhotite-arsenopyrite veining/flooding within volcano-sedimentary rocks have been discovered: the Whale Tail, V and Mammoth zones. The Whale Tail and V zones appear to be offset mineralized corridors striking east-northeast to northeast and dipping moderately to steeply southeast.
The Whale Tail deposit has been defined over at least 2.3 km of strike length and from surface to 915 m depth; it includes the Whale Tail ore shoot in the mineralized chert-iron formation sequence plunging shallowly east-to-northeast. Whale Tail remains open at depth and along strike.
Immediately north of Whale Tail, the V Zone consists of a series of parallel stacked mineralized structures striking northeast and extending from near surface to as deep as 707 m below surface; the southeast dip of the structures is approximately 30 degrees near surface and steepens to 60 to 70 degrees at depth, where there are at least two sub-parallel structures. The V Zone ore shoot, defined in 2018, is a mineralized corridor 100 to 150 m wide, locally more than 300 m wide, plunging shallowly eastward, extending from approximately 350 m to more than 700 m depth.
Mining
The Company has conducted surface mining at Meadowbank from a series of three pits all within 7 km of the processing plant. Water retention dikes were built to allow for mining beneath shallow lakes. The mine operated year-round using conventional drilling, blasting, and truck-and-shovel methods. Waste rock was used for construction or placed 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. Mining concluded at the Meadowbank site in 2019.
A conventional open-pit mining operation has been developed on the Whale Tail deposit at the Amaruq site, with ore being transported using long haul off-road type trucks to the mill at the Meadowbank facilities for processing. Following construction of two associated water retention dikes, mining from the Whale Tail pit began in the first quarter of 2019 with mining rates ramping up throughout the rest of 2019.
An exploration ramp started at Amaruq in early 2018 has improved the efficiency of evaluating the potential for an underground operation, accelerating drilling activities designed to infill and convert mineral resources and to expand the deposits.
Processing
The 11,000-tonnes/day Meadowbank gold processing plant uses conventional technology adjusted to the Arctic climate. After two stages of crushing and grinding, any "free gold" is then 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 a sulphur-dioxide-air cyanide destruction circuit to ensure that no cyanide escapes to the environment. Tailings from the Meadowbank mine have been placed in the permanent tailings facility. All water from the tailings pond is pumped back to the plant for reuse, making this a zero-discharge system. The processing of ore from the Portage pit and stockpiles at Meadowbank was completed during the fourth quarter of 2019.
Modifications to the processing plant to treat Amaruq ore were completed in the first quarter of 2019 — specifically, the addition of a gravity preconcentration process followed by a regrind mill. The plant is expected to operate at 9,000 to 10,000 tonnes/day processing Amaruq ore once mining ramp-up is completed. Gold recovery is expected to be 93% for Whale Tail ore and 95% for V Zone ore.
Permitting for in-pit disposal of the Meadowbank mill tailings in the depleted Meadowbank pits was received and in-pit tailings deposition began in July 2019.
Exploration
The Whale Tail deposit has been defined over at least 2.3 km of strike length and from surface to 915 m depth.
The conversion drilling program continues to demonstrate the extension of high-grade mineralization below the proposed pit outline, while the level of confidence in the geological model continues to improve.
In 2019, drilling from the exploration ramp into the Whale Tail North Zone, below the existing mineral resources in the eastern part of Whale Tail, has shown the potential for the development of new mineral resources approximately 100 m north of the Whale Tail underground mineral resources at depth.
The Whale Tail deposit remains open to the west at depth, and to the east along a shallow plunge corresponding to the main ore shoot. A small portion of Amaruq's current mineral reserves and mineral resources are in the Whale Tail North structure.
The V Zone consists of a series of parallel, stacked mineralized structures striking northeast from near surface to as deep as 707 m below surface. The dip of the structures is approximately 30 degrees near surface, and steepens to 60 to 70 degrees at depth, where there are at least two sub-parallel structures. The V Zone ore shoot is a mineralized corridor 100 to 300 m wide plunging shallowly to the northeast and extending from approximately 350 m to more than 700 m depth. In second half of 2019, conversion and exploration drilling continued to return positive results along the interpreted V Zone ore shoot.
In 2020, the Company expects to test regional targets at Amaruq with a focus on open-pit potential, as well as other near-surface targets close to existing road infrastructure between Amaruq and Baker Lake.