The Westwood gold project is located on the Doyon property in the municipality of Preissac, in Bousquet Township, approximately 40 km east of the town of Rouyn-Noranda, in the province of Québec, Canada.
The first reported exploration activities in the Cadillac area date back to 1910. Mineralization at Doyon was discovered in the 1960?s by the prospector Arthur Doyon.
Cambior acquired 50% interest in the Doyon mine in 1986 from Soquem; it acquired the balance of interest from Barrick in 1998. Iamgold Corporation took over Cambior in November 2006.
The project is 2.5 km east of Iamgold?s Doyon mine and is located within the Cadillac belt of the Abitibi region of northwest Quebec. The Doyon mine ceased production at the end of 2009. The Doyon shaft will be in operation until the Westwood shaft is completed and functional to the 1,080 m elevation, expected at the end of 2010.
The 2010 inferred mineral resources were estimated at 9.4 Mt at 11.4 g/t gold for 3.4 Moz.
Mining operations would be conducted underground. Over a projected mine life of 16 years, based on current resources, Westwood will produce an average of 186,000 ounces of gold annually at an average cash cost of $358 per ounce, generating a pre-tax operating cash flow of $822 million.
The Westwood project is planned for commercial production in early 2013.
Canada is a developed country, a member of G8 and OECD. It is located north of the parallel 48 which separates it from USA its largest economic partner. Canada is the world?s second largest country by total area and has an economy that boasts strong natural resources.
The Westwood project is located on the Doyon property in the municipality of Preissac, in Bousquet Township, approximately 40 km east of the town of Rouyn-Noranda, in the Abitibi region of the province of Québec. Quebec (?where the river narrows? in Algonquin) is an east-central province inhabited by a predominantly French speaking population.
The property is year-round accessible from the Provincial road no.117 via the secondary road leading to Mont-Brun and Aiguebelle National Park and then by following a 4 km paved road.
The site is characterized by low elevations situated at about 340 m asl. Numerous permanent and temporary creeks drain the clayey glacial soil that can be water-logged during the summer season.
Climate varies from dry-hot (up to 35 deg C) in summer time to cold (down to -40 deg C) and snowy in winter.
Wildlife similar to the one protected in the Aiguebelle National Park could be observed on the property. The park hosts abundant wildlife and is home to the largest concentration of moose in the Abitibi region. Over 450 beaver dams have also been located within the park?s boundaries.
The Westwood project is part of the Doyon-Bousquet-LaRonde (DBL) mining camp which is recognized as Quebec?s largest gold ? copper ? zinc ? silver producing district hosting some 25.5 Moz gold.
The project is located in glaciated terrain underlain by Archaean volcanic rocks of the Blake River Group and the metasedimentary Cadillac (CG) and Kewagama Groups. Gold bearing VMS and disseminated sulphide zones occur in the eastern part of the Doyon property and are known as the Westwood and Warrenmac showings.
The origin of the gold in the DBL camp has been extensively debated in the past and three models have been proposed: synvolcanic, multi-stage, and syn-deformation.
Westwood mineralization is presented as Au-rich sulfide veins, stockworks and disseminations.
Mineralization has been identified at Westwood from a 60 meter depth to as deep as 2,600 meters, within three sub parallel zones that extend along a strike length in excess of 1.8 kilometers.
The 2010 inferred mineral resources were estimated at 9.4 Mt at 11.4 g/t gold for 3.4 Moz. Measured and indicated mineral resource stood at 408,000 t at 7.5 g/t gold for 98,000 oz.
Mining & Operations
Mining of the Westwood project was all planned using the long hole retreat method. All the stopes will require backfill in order to maintain stability and low dilution. Paste backfill combined with the use of rock-fill was the option retained. This method was also used at the adjacent Doyon mine.
All stopes were planned 15 m high by 15 m long with minimum 2.5 m true thickness. In most of the cases, this thickness is well over the thickness of the mineralized zone. With the current method 1.2 m thickness in stopes could be achieved using the equipment already selected.
The production rate will be of 2,200 tpd obtaining 200,000 ounces or 800,000 tpy. The mine start-up should take four years and it should be in production for at least 16 years, based on currently identified resources.
The mine will go into production after the company?s nearby Doyon and Mouska mines have been closed. The Doyon mine ceased production at the end of 2009. The Doyon shaft will be in operation until the Westwood shaft is completed and functional to the 1,080 m elevation, expected at the end of 2010.
The Westwood project is planned for commercial production in early 2013.
Ore processing will be carried out at the existing Doyon mill complex. However, the project will be split into two phases.
In the first phase, only the gold mineralization will be treated at the mill. During the first year of operation the Westwood mineralization will be processed at a rate of 700,000 tpy. Subsequently, the tonnage will be increased to a capacity of 800,000 tpy. The Mouska copper circuit will be temporarily converted to a desulphuration circuit. The existing grinding, leaching, absorption and stripping circuits will require some upgrade. Cyanide destruction capacity will be increased to treat the generated tailings.
In the second phase, the capacity of the existing copper flotation circuit will be increased. A zinc flotation circuit will be added and a new desulphuration circuit will be set up to begin tailings reclamation.
The ore will be sent by truck to the Doyon mill - two kilometer haul distance. The crushing will be carried out on surface with the available equipment. No modification is planned for the crusher plant. The ore will be conveyed to the milling ore bins using the existing conveyor system.
The ore grinding circuit will utilize the existing SAG mill and a 1,000 HP ball mill in closed circuit with its own classification. The existing 350 HP ball mill will be used to regrind the zinc rougher concentrate.
The flotation process will only be used in the second phase. The current Mouska flotation circuit will be used for copper flotation. Three tanks, Cell (1+2), will be added to increase the retention time for the rougher and the scavenger. The current copper concentrate thickener (3.6 m) will be upgraded to a bigger thickener (6 m) in order to meet the higher demand. A new circuit will be installed for zinc flotation. The preliminary flotation test results indicate excellent copper and zinc recoveries with good concentrate grades.
The existing disc filter (2 disc x 4?) used for copper filtration will be replaced by a bigger disc filter (4 disc x 4?) and will be moved to the concentrate shed. For the zinc concentrate, a new pressure filter will be installed in a closed storage facility. The zinc concentrate will be put into a 120 tonne silo. Each day, the concentrate will be transported and put into storage at Cadillac for train shipping.
All the cyanide will have to be destroyed because it is not compatible with the desulphuration and paste backfill processes. The paste backfill plant will be utilized early in the first phase. All the tailings will be treated in the cyanide destruction plant.
Desulphuration is a process that involves non-selective flotation of all sulfides present in the tailings. The result of the desulphuration process is a sulfide concentrate that will go to the paste backfill plant and a final tailing exempt from sulfides that will be pumped to the tailings ponds.
The paste backfill plant will have to be moved because it is currently too far from the Westwood shaft.
Because it has been used for a long period of time and suffered many repairs, the electrowinning circuit will have to be replaced.