The Roberto deposit on the lonore property is the star of a major new gold mining camp, and 100% owner Goldcorp has big plans for the advanced exploration project.
The 244-km2 property lies on the east side of the Opinaca Reservoir in the remote James Bay region of northwest Quebec, 350 km north of Matagami and the prolific Abitibi region. But thanks to Hydro-Qubec installations, the area already has excellent infrastructure including low-cost electricity within 70 km. A gravel road links the west end of the reservoir to the James Bay paved highway. In 2008, a 60-km gravel road north of the reservoir will complete the access all the way to the 100-person exploration camp, and a 1,500-m airstrip will be built near the camp.
A 2004 gold exploration program by Quebec City-based junior Virginia Gold Mines led to the discovery of the Roberto gold deposit 6 km northeast of the Ell Lake copper showing, which had been found by Noranda Exploration in 1964. The Virginia crew found Roberto by tracing a train of intensely altered and mineralized glacial boulders back to outcrop. They staked it, and got to work.
The property name, “lonore”, had been bestowed in 2001 by geology professor Michel Gauthier, who was following Quebec tradition in assigning a woman’s name to a potential mine. He called the site “lonore” after a woman named in a song by French songwriter Georges Brassens.
The gold deposit lies between two 2.7-billion-year-old subprovinces, centred around the 10-km-wide Ell Lake tonalite-diorite intrusion. There are several gold lenses hosted by a sequence of metasomatized alumino-silicate-rich wackes, folded into an overturned synform dipping 65-75E. The mineralized zones are stockworks of quartz-tourmaline-actinolite-arsenopyrite-pyrrhotite veins and veinlets with potassic alteration and tourmaline replacement zones. The second of three deformational events in the area generated a west- to northwest-trending penetrative fabric. Brittle faulting and mylonite define the mineralization.
Four parallel lenses of the Roberto deposit are each 2- to 25-m thick and 75- to 1,000-m long, extending from surface to a depth of at least 1,100 m. In map view, the Roberto and other parallel zones form a 650-m-wide crescent shape open to the east, 1.9 km from one side to the other. Drilling has confirmed the continuity of the mineralization; the deposit remains open at both ends and at depth.
Opinaca/Goldcorp takes over
The Roberto discovery sparked keen interest in the area, catching the attention of Goldcorp Inc., which on Dec. 5, 2005, announced an agreement to obtain 100% interest in the lonore project. Its method was circuitous: Goldcorp acquired the whole of Virginia Gold Mines (VGM), and then transferred all assets except lonore to a former VGM subsidiary named Virginia Mines Inc., which became an independent company under the former VGM management.
The all-stock deal valued lonore at a hefty US$420 million, but Goldcorp got a lot for its money. The project lay in the heart of one of the most promising new gold districts in North America. Virginia’s drills were proving up a rich and consistent gold deposit. There is nearby accessible infrastructure, and Quebec is considered to be a mining-friendly regulatory environment.
Goldcorp took over the project on Apr. 1, 2006, to be managed by subsidiary Les Mines Opinaca Lte. CMJ interviewed Goldcorp’s general manager-projects, Canada and U.S.A., Claude Lemasson, about lonore in mid-May 2007.
The environmental baseline studies that began last year continue. A comprehensive environmental and social impact assessment was completed early this year for the access road and the airstrip.
Virginia Gold had drilled 86,000 m in 247 holes at the Roberto deposit to the end of 2005. In 2006, Goldcorp added 76,000 m of infill drilling in 245 holes. The core of the deposit was drilled on 25×25-m spacing to a depth of 250 m, and 50×50-m spacing below that. In all, Opinaca Mines spent $18.7 million at lonore to the end of 2006.
In March 2007, Opinaca staff helped by engineering consultants SRK of Toronto and Met-Chem of Montreal completed a scoping study based on drilling in the core section to the 800-m depth. The study recommended one or more open pits to exploit the near-surface mineralization plus an underground mine served by a series of ramps. The pits would require dikes to hold back the waters of the Opinaca Reservoir.
As the study was being finalized, some of its results became obsolete. Ongoing exploration was finding that the gold-bearing lenses were continuous to at least 1,100 m depth and along strike, with no end in sight. This changed the whole picture for lonore. The idea of open pits protected by dikes has been set aside. Instead Opinaca is looking at building a shaft to recover most of the ore, with ramps for the initial, shallow part of the mine. The mining method will probably be cut-and-fill, with about half as much waste as ore.
Although lonore’s first resource figures will not be released until early June, Lemasson estimates that the deposit contains over 2 million oz of gold above the 750-m depth, and at least another 2-million-oz gold resource below, at an average grade of 9 g/t Au.
The team of eight senior staff has been hired and is beginning a prefeasibility study that should be complete by the end of 2007. The company has budgeted $16.0 million for exploration work in 2007, including 70,000 m of drilling by up to five rigs as well as geological mapping, geochem and geophysics. Another $15 million will be spent in 2008 on construction work and a prefeasibility study.
The studies and permitting will continue to the end of 2008. Development and construction will begin in the third quarter of 2007 and continue to the second half of 2010. Most of the construction will take place in 2009-10. The ramp will be built in the first half of 2009, taking samples and mining at the same time. The mill should be operational in 2010 at an estimated throughput of 2,500-4,000 tonnes/day.
Based on his experience at the Red Lake mine, Lemasson estimates that a shaft from surface to 1, 000- to 1,500-m depth would take three years to construct including the development work, starting in 2009, so it would be fully operational in 2012. If lonore proves to have 4 million oz of gold in reserves, a very rough estimate of the mine life would be 12 to 15 years, producing over 200,000 oz/year.
He adds, “There could be more. We are definitely there to stay.” Opinaca Mines is currently involved with several exploration companies in the lonore area including Virginia Mines, Eastmain Resources, Azimut Exploration and Beaufield Resources. Depending on their discoveries, the lonore mill could have some custom work in its future.
The Cree community of Wemindji 190 km to the west is the nearest town to the project and home of the First Nation group with the most interest in it. Opinaca Mines quickly got to know the neighbours, hiring a full-time community affairs manager and establishing a liaison committee with the Cree Nation of Wemindji, which has held various meetings. The company also has begun dialogue with other stakeholders including other municipalities and businesses, Hydro-Qubec and the Quebec government.
Opinaca has already signed short-term employment and transportation service agreements with the community, hiring Wemindji Cree for up to a quarter of the 100 technical and support staff jobs at the lonore site. Current discussions (including training programs, future employment, business opportunities and the protection of the environment) are expected to result in a long-term collaboration agreement with the Cree Nation of Wemindji later this year.