
OVERVIEW
The 100% owned Lynn Lake gold project is a highly prospective past-producing gold camp consisting of five near surface deposits with significant existing infrastructure. The Lynn Lake project consists of two primary deposits; the MacLellan Mine and the Gordon Mine, which were the subject of a positive Feasibility Study was published in December 2017.
Location
The Lynn Lake project is located in Lynn Lake, Manitoba, Canada.
History
In November, 2014, AuRico Gold entered into a joint venture agreement with Carlisle Goldfields, acquiring a 25% interest in the Lynn Lake project for an initial cash contribution of C$5 million, with the option to earn up to a 60% interest by funding C$20 million on the Project over a three-year period and delivering a feasibility study. Alamos Gold merged with AuRico Gold in 2015 and in January 2016, Alamos consolidated full ownership of Lynn Lake through its acquisition of Carlisle Goldfields. Alamos published a positive Feasibility Study on the project in December 2017.
GEOLOGY AND MINERALIZATION
The project is situated in the North belt of the Lynn Lake Greenstone Belt within the Churchill Structural Province of the Canadian Shield. The North belt is a north-facing homocline and consists of rhyolites, overlain by andesite and basalt, sedimentary rocks and an upper balaltic unit. Both deposits are located within this belt, which has been termed the “Rainbow Trend”.
MacLellan Mine Project
The mineralized system is hosted within a unique stratigraphic sequence known as the Agassiz Metallotect within the Wasekwan Group rocks of the North belt. The Agassiz Metallotect comprises interlayered siltstones, basalts, iron formations and minor felsic volcanics. The MacLellan Mine is hosted by an interbedded sequence of biotite-rich to siliceous siltstone and high magnesium basaltic flows and minor tuffs. Overlying and underlying this mine sequence are massive and fragmental mafic volcanic rocks. The mine is subdivided longitudinally into three mineralized deposits, from west to east they are the Rainbow-Dot deposit, the MacLellan deposit and the Nisku deposit. All of these deposits are located south of a major east-west trending fault structure known as the North Shear Zone.
Gordon Mine Project
The deposit is hosted in a Pre-Cambrian sedimentary iron formation. The iron formation in the Farley Lake area is 6 kilometres long by 600 metres wide and is predominantly composed of an oxide facies iron formation that is intercalated with clastic sediments. Mineralization is in discordant sulphide lenses within silicified, chloritized and sulphidized oxide facies iron formation. The Gordon deposit is thought to be an epigenetic iron-formation hosted gold deposit.
MINING AND PROCESSING
Mining
Both the Gordon and MacLellan deposits will be developed using conventional shovel/truck open pit mining methods with owner mining assumed within the Feasibility Study. The Gordon and MacLellan deposits are expected to operate concurrently for the first six years of operation, with Gordon to be depleted first given its higher grades and lower stripping ratio. As the Gordon pit nears depletion, mining equipment will be transferred to MacLellan and utilized over the remainder of its mine life.
Following a one year pre-production period at Gordon and two-year pre-production period at MacLellan, combined mining rates are expected to range between 20.5 and 27.0 Mt of material per year over the first seven years. This includes peak mining rates of 13 Mt at Gordon and 24.7 Mt at MacLellan.
Loading of ore and waste rock is planned to be carried out with two 300 t class hydraulic shovels and two front end loaders, paired primarily with 144 t capacity mine trucks. Ore from MacLellan will be hauled to the primary crusher (located to the south of the pit). All ore from Gordon will be transported approximately 55 km to the process facility at MacLellan via a fleet of 23 highway trucks, each with a capacity of approximately 30 t.
Processing, Metallurgy and Infrastructure
Lynn Lake’s process plant has been designed as a conventional milling operation with a nominal capacity of 7,000 tpd. The proposed plant design is based on leach/carbon in pulp (“CIP”), and will consist of crushing, grinding, thickening, pre-aeration and leaching, CIP, cyanide detoxification, carbon elution and regeneration, and gold smelting.
Based on test work, gold recoveries from Gordon are expected to average 92.9% and gold and silver recoveries from MacLellan are expected to average 91.4% and 49%, respectively. Over the life of mine, combined gold recoveries are expected to average 92.0%.
Power to the MacLellan site, which will host all the process facilities and major infrastructure, will be supplied from Manitoba Hydro through the commercial electricity grid. The existing power line to the Town of Lynn Lake will be modified from 69kV to 138 kV, and a 7 km 138kV overhead line will be built to the MacLellan site.
The Gordon site’s electrical demands will be met by two 300 kW diesel generators in duty/standby configuration.
The tailings management facility (“TMF”) will be constructed approximately 3 km northeast of the planned open pit and plant site at MacLellan. Additional dam raises are planned for years two, six and nine to accommodate the life of the mining operation. The majority of operational water required for the process plant will be reclaimed from the TMF.