Forming part of the LaRonde Complex, the 7,000-tonnes/day LaRonde mine and processing facility has produced over 7 million ounces of gold as well as valuable by-products. The LaRonde mine still has 2.5 million ounces of gold in proven and probable mineral reserves (12.3 million tonnes grading 6.36 grams of gold per tonne) as at December 31, 2022.
The LaRonde mine achieved commercial production of its deep extension (that is, below Level 245) in November 2011, where most of its ore is now mined. LaRonde currently has a mine life lasting through to 2036. Below approximately 2.8 km depth, the LaRonde mine divides into two parallel lobes called the “East mine” and the slightly offset “West mine”.
The LZ5 mine is on the Bousquet property, approximately 2.5 km west of the Penna Shaft on the LaRonde mine property. Previous property owners had partly exploited the deposit by open pit. Following the completion of a positive internal technical study, LZ5 was approved for development in February 2017 and commercial production was achieved on June 1, 2018.
LZ5 has proven and probable mineral reserves of 710,000 ounces of gold (10.4 million tonnes grading 2.12 grams per tonne gold) as at December 31, 2022. Mineral reserves and mineral resources from the adjacent, 100%-owned Ellison property were included in LZ5 mineral resources and mineral reserves beginning in 2020. The LZ5 mine is expected to maintain a production rate exceeding 3,100 tpd through 2028 and before declining in the final years of the current mine life of 2032.
The entire LaRonde Complex hosts 3.2 million ounces of gold in proven and probable mineral reserves (22.7 million tonnes grading 4.42 grams of gold per tonne) as at December 31, 2022.
During 2022, the LaRonde Complex produced 356,337 ounces of gold and 622,000 ounces of silver plus by-product zinc and copper.
The current guidance issued by the Company in February 2023 reflects the change in the mining rate at LaRonde mine. Total gold production at the LaRonde Complex in 2023 and 2024 is now forecast to be approximately 275,000 ounces and 280,000 ounces, respectively. Gold production is expected to increase to 310,000 ounces in 2025 and reach an annual run-rate of approximately 325,000 ounces per year in 2026.
Geology
The LaRonde property is located in the southern portion of the Archean-age Abitibi volcanic belt, within the Bousquet Formation of the Blake River Group of volcanic rocks. The LaRonde and LZ5 deposits occur at the eastern end of the east-west-trending Doyon-Bousquet-LaRonde mining camp, which includes the Mouska, Doyon, Bousquet 1 and Bousquet 2 gold deposits. The most important regional structure is the Cadillac-Larder Lake fault zone, located approximately 2 km south of the LaRonde property.
The LaRonde deposit is a gold-rich volcanogenic massive sulphide deposit with significant silver, zinc and copper credits. LaRonde lenses were formed mainly by sulphide precipitation from hydrothermal fluids on the seafloor and by replacement below lenses. The stacking of the LaRonde lenses is the result of successive volcanic events, intercalated by cycles of hydrothermal activity associated with reactivation of synvolcanic faults.
The LZ5 deposit, in contrast, is composed of gold-rich disseminated to stringer sulphide mineralization with a significant silver credit.
Mineralization
At the LaRonde mine, gold-copper and zinc-silver mineralization occurs in the form of massive and disseminated sulphide lenses. The presence of silver and base metals adds considerably to the value of LaRonde’s gold ore, reducing the total cash cost to produce each ounce of gold on a by-product basis. Five different mineralized horizons are known to exist adjacent to the Penna Shaft. The zinc-silver mineralization with lower gold values, common in the upper mine, grades into gold-copper mineralization within the lower mine. The predominant base metal sulphides are chalcopyrite (copper) and sphalerite (zinc).
Zone 20 North contains the majority of the mineral reserves and mineral resources at the LaRonde mine. The Company believes that Zone 20 North is one of the largest gold-bearing massive sulphide mineralized zones in the world and one of the largest known mineralized zones in the Abitibi region of Ontario and Quebec. Zone 20 North extends from 800 metres below surface to at least 3,700 metres below surface, and remains open at depth. With increased access on the lower levels of the mine (i.e., below Level 245 and from the internal shaft on levels 257 and 278), the broad transformation from a zinc/silver orebody to a gold/copper deposit was effectively completed in 2017. However, the development of the West mine area, between Levels 278 and 314, provided access to a new zinc/silver rich zone beginning at the end of 2017.
The LZ5 horizon consists of a 4- to 30-metre-thick horizon of disseminated to stringer sulphide mineralization containing 5% to 20% pyrite and traces of chalcopyrite with rare millimetre-wide grains of visible gold. The LZ5 horizon has a large geological footprint and has been estimated to contain a mass of more than 26 million tonnes. The LZ5 horizon can be followed over 900 metres of east-west strike length over the Bousquet property and another 400 metres on the Ellison property for a total strike length of 1,300 metres. LZ5 has been traced vertically for almost 1,000 metres, and it shows a steep dip to the southwest. In an enlarged area of LZ5, there is gold enrichment near the margins of the economic envelope. LZ5 includes two high-grade portions named Zone 5 Footwall and Zone 5 Hanging Wall.
Mining
Access to LaRonde’s underground mining operation is through the 2,250-metre-deep Penna Shaft, which was completed in March 2000 and remains the deepest single-lift shaft in the Western Hemisphere. The internal Shaft #4 extends 823 metres to 2,858 metres depth to provide access to even deeper ore at the lower part of the orebody, and has been at the centre of the LaRonde mine extension project initiated in 2006.
At the LaRonde mine, longitudinal and transverse longhole open stoping are the main mining methods used for the extraction of the orebody. The longitudinal method is used for narrow ore widths above Level 215. The transverse mining method is the standard mining method for the operation below Level 215 and is well adapted to address concerns regarding the high stress conditions encountered in the mine’s lower levels.
In 2023, the LaRonde mine is transitioning to pillarless mining and an adjusted development plan to manage seismicity within the mine, resulting in a lower mining rate when compared to the prior year.
Below approximately 2.8 km depth, the LaRonde mine divides into two parallel lobes called the East mine and the slightly offset West mine. In 2021, the Company commissioned a new cooling plant in the East mine. In 2023 the Company expects to commission new booster fans at Level 275.
The LaRonde Complex has been successful at incrementally implementing automation for its production activities and is increasingly relying on this technology.
For instance, the mucking and hauling fleet at LZ5 is an automated fleet. The scoops and trucks at LZ5 can be operated remotely from surface when no personnel are underground. It has allowed the mine to remain productive during shift changes and night shifts on the weekend. The transformation of these previously “lost” hours into productive hours has improved the productivity of the mine.
Production in Zone 11-3 at the LaRonde mine is expected to start in the third quarter of 2023 and it will add additional flexibility in the LaRonde mine production plan.
LZ5 is mined from underground ramp access and the transverse longhole stoping method is used in sectors with poor ground quality while the longitudinal retreat method is used in areas with better ground quality, or the width of the orebody cannot justify the costs of transverse mining.
Processing
Ore is processed at the LaRonde mineral processing complex, which includes copper and zinc flotation as well as precious metals recovery and refining. The processing plant produces doré bars containing gold and silver, as well as zinc and copper concentrates that carry valuable gold and silver credits.
The plant has a daily capacity of 7,000 tonnes of ore and has been expanded four times since it opened in 1988. In addition, a dedicated 2,000-tonnes/day carbon-in-leach processing facility has treated ore trucked from the LZ5 mine and refined its concentrates into doré bars. This smaller LZ5 processing facility formerly treated ore from the now closed Lapa mine.
In 2019, the Company was granted a revision to the Certificate of Authorization at the LaRonde Complex, which allowed for the processing of ore from LZ5 through the LaRonde mill circuit. As a result, the Company began reporting the operational parameters from both the LaRonde and LZ5 mines on a combined basis as the LaRonde Complex starting in 2020.
The LaRonde plant also treats concentrate pulp trucked from the Goldex mill. The material is sent to the LaRonde leaching/carbon-in-pulp circuit for gold recovery along with LaRonde residual pulp.
The dry stack tailings facilities were commissioned in the fourth quarter of 2022 and they have been operating as expected since commissioning.
The LZ5 processing facility is planned to be idled late in the third quarter of 2023 to take advantage of the approximately 2,000 tpd of excess capacity in the LaRonde mill.
Exploration
Diamond drilling is used for exploration on the LaRonde Complex properties. In 2022, 59 holes (31,460 metres) were drilled for conversion and exploration.
The main focus of the 2022 exploration program at the LaRonde mine was continuing the investigation and conversion of Zone 20 North at depth in both the West mine and East mine areas by extending drill targets down to 3.5 and 3.6 km depth. Exploration also continued at the adjacent Bousquet property with two holes being completed from Bousquet 2 level 9-0 exploration drift. The objective was to investigate the extent of Zone 3-1 between 1.0 and 3.0 km depth.
Exploration drilling was also conducted from surface at LZ5 to convert Zones 4 and 4-1 on the Ellison property and target the Zone 5 extension at depth on the Ellison property towards the west.
In 2023 at the LaRonde Complex, the Company expects to spend $1.6 million for 13,200 metres of capitalized drilling and $9.8 million for 43,000 metres of exploration drilling into targets, including Zone 20N in the East and West mines, Zone 3-1, Zone 3-4, Zone 4 and Zone 5, with the aim of adding new mineral reserves and mineral resources to extend expected mine life further into the 2030s.
The planned work program includes extension of the exploration drift on Level 215 by 1,060 metres to the west to provide drill platforms to test the vertical extensions of known zones on the Bousquet property and below the LZ5 deposit.