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. It has 98,000 ounces of gold in proven and probable mineral reserves (1.6 million tonnes at 1.89 g/t) as of December 31, 2018. It is anticipated 2019 will be the last year of production at the Meadowbank mine.
The 94,548-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 gold zones and several other targets. At December 31, 2018, the Amaruq satellite deposit at Meadowbank was estimated to contain open pit proven and probable mineral reserves of 2.9 million ounces of gold (24.9 million tonnes grading 3.59 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, 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 Meadowbank Complex (including the Meadowbank mine and Whale Tail pit) is expected to produce 200,000 ounces of gold in 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 2025.
Permitting for the Amaruq Phase 2 expansion, including an open pit at the V Zone and underground operations, is expected to be completed in late 2020. 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 have been 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 kilometres 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 kilometres of strike length and from surface to 915 metres 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 metres 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 metres wide, locally more than 300 metres wide, plunging shallowly eastward, extending from approximately 350 metres to more than 700 metres depth.
Mining
The Company has conducted surface mining at Meadowbank from a series of three pits all within 7 kilometres of the processing plant. Water retention dikes were built to allow for mining beneath shallow lakes, using a unique in-water dike construction method. The mine has been in operation 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 is expected to conclude at the Meadowbank site before the end of 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 and is expected to reach the design rate of 9,000 to 10,000 tonnes per day by year-end 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-tonne/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 is expected to be 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. Gold recovery is expected to be 93% for Whale Tail ore and 95% for V Zone ore based on testing.
In May 2019, the Company received the final approvals to allow for in-pit tailings deposition at Meadowbank. The Company believes that in-pit tailings deposition is a safer and more environmentally sustainable option to deal with the Amaruq tailings. In addition, this process is expected to result in lower sustaining capital over the life of the mine.
Exploration
Exploration is being conducted at the Amaruq satellite deposit. A 32,800-metre exploration drilling program (budgeted at approximately $8.1 million) and a 20,300-metre conversion drilling program (budgeted at approximately $4.4 million) was initially planned for 2019. The exploration program is focused on Whale Tail deep extensions toward the west and the east, V Zone deep extensions, and extensions of the known mineral resources of the Whale Tail North structure toward the east to fill in the gap between the V Zone and at depth. New concepts will be tested regionally to search for new shallow mineralization, focusing on areas close to the current infrastructure.
As a result of ongoing positive exploration drilling results at Whale Tail and V Zone at depth, an additional $21 million was added to the capital forecast for the Amaruq underground project in mid-2019. The extra capital will primarily be used to fund increased underground development and an additional 15,600 metres of conversion drilling from underground, bringing total conversion drilling at Amaruq to 35,900 metres for the year.