The Macassa mine is located in an area with well-developed infrastructure, including a provincial highway, a railway system and a private airport. Macassa ore is processed on-site at the Macassa mill.
The Macassa property was first explored in 1931, leading quickly to a gold discovery, and in October 1933 Macassa’s first mill began processing ore. Macassa was in continuous production from 1933 until 1999, when operations were suspended and placed into care and maintenance due to the declining gold price.
Macassa resumed operations in 2002, and with the discovery of the high-grade South Mine Complex (SMC), was able to increase production levels significantly above historic levels and make Macassa one of the highest grade gold mines in the world.
Successful ongoing exploration drilling continues to extend the SMC mineralization and add to the mine’s mineral reserves and mineral resources in support of extending mine life.
The commissioning of the Shaft #4 production hoist in the first quarter of 2023 has started a new chapter in the life of the Macassa mine, with the new shaft expected to increase production, lower unit costs, improve working conditions, and increase exploration capacity.
Geology & Mineralization
The gold mineralization at Macassa is found along breaks or faults, in veins as quartz filled fractures, as breccias and as sulphide rich (pyrite) zones. There are multiple mineralized breaks, named the ‘04, ‘05, No.6, Kirkland Lake Main and the Kirkland Lake North and South branches. The breaks strike 60 degrees northeast and dip 70 to 80 degrees south in keeping with the Timiskaming trend. The trend of the gold mineralization in the Kirkland Lake camp conforms to the 60 degree westerly plunge of the syenite intrusives.
The SMC was a significant discovery, with the zone having a different character than the zones mined historically at Macassa. The SMC is associated with a cross-over structure that links the ’04 / Main Break with the Amalgamated Break. The mineralization trends parallel to the main structures but has a much flatter dip ranging from 20 to 50 degrees south. SMC mineralization has been found to have greater widths and contain higher grades than the main zones. Considerable potential exists for future exploration drilling to identify additional parallel and stacked zones located above, below and along strike of the known SMC Zone.
Mining
Mining at Macassa is currently underway at an average rate of 1,000 tpd across two mining horizons: the historical Main/’04 breaks and the SMC Zone. Mining is conducted primarily via overhand and underhand cut-and-fill and a small portion of long hole methods.
All stopes are backfilled with either paste fill, cemented rock fill or loose waste rock.
The Macassa mine was the first mine in the world to use lithium ion battery operated trucks and loaders.
In early 2023, the Shaft #4 production hoist saw commissioning of the full material handling system, and development work served to connect the new shaft infrastructure to the existing mining areas. Construction of the conveyor loadout station was also completed in early 2023.
Processing
The Macassa mill was built in 1986 and originally designed for a throughput of 725 tonnes per day. The mill was subsequently expanded to its current capacity of 1,650 tpd. Processing of ore at Macassa starts with crushing and grinding before it enters the leach tanks for cyanidation. Then, it flows through a carbon-in-pulp circuit, followed by a Zadra recovery process. The concentrate is melted in an induction furnace where doré is poured that typically contains 70% to 85% gold, and 5% to 10% silver.
Exploration
With the completion of the merger with Kirkland Lake Gold in 2022, Agnico Eagle now controls six of the original producing mines along the Main Break in the Kirkland Lake mining camp. The underground workings of these mines are all interconnected and tie into production areas at the Macassa mine.
The Company plans to continue to work with the historical data to assess the potential of longer-term exploration targets along the Main Break. The near-term focus will be to assess the mineral potential to the east and along the Main Break below the 5800 Level at Macassa and east onto the Kirkland Minerals and Teck-Hughes properties. Any significant discoveries on these properties could provide incremental sources of ore for the Macassa mill.
At the Macassa mine in 2023, the Company expects to spend approximately $18.4 million for 145,400 metres of capitalized drilling to increase and upgrade mineral resources. Another $1.2 million is budgeted for 9,500 metres of exploration drilling to continue to investigate extensions of key targets at the South Mine Complex (East, West, Upper and Lower), Main Break, '04 Break, Amalgamated Break and Near-Surface. In addition, $14.1 million of capitalized exploration will be spent to further develop exploration drifts in order to drill to the east of current mine infrastructure along strike and at depth of the South Mine Complex and Main Break towards the historic Lake Shore mine and to access, develop and infill with underground drilling the mineralization on the Amalgamated Kirkland (“AK”) property.
Development Projects
Internal evaluations are underway to assess potential production opportunities at the Macassa Near Surface and AK deposits, the Upper Beaver project and the newly acquired Wasamac project. These evaluations are expected to be completed by year-end 2023.
Near Surface and AK deposits
The Company is evaluating the possibility of using the existing Macassa Near Surface Zone infrastructure to mine the AK deposit as early as 2024. Production could average approximately 40,000 ounces per year, at total cash cost per ounce of $650-$750. This production is expected to have a positive impact on cash flow generation at Macassa.
As at December 31, 2022, the Macassa Near Surface deposit had proven and probable mineral reserves of 16,000 ounces of gold (92,000 tonnes grading 5.31 g/t gold) and AK had proven and probable reserves of 100,000 ounces of gold (596,000 tonnes grading 5.20 g/t gold).
Upper Beaver project
The Upper Beaver deposit is located approximately 27 km from the Macassa mine, and 60 km from the Company’s Holt mining complex in Ontario. The Company is currently reviewing the concept of leveraging the Macassa infrastructure or the Holt Complex infrastructure and the shaft sinking experience at Macassa to enhance project returns at Upper Beaver.
At December 31, 2022, Upper Beaver had proven and probable mineral reserves of 1.4 million ounces of gold (8.0 million tonnes grading 5.43 g/t gold).
More information on the Near Surface, AK and Upper Beaver deposits can be found on the Kirkland Lake Regional webpage.