Goldcorp advancing Eleonore project toward 600,000-oz/y goal

Four new mines in four years is an ambitious goal for any developer, but Goldcorp is well on its way: Pueblo Viejo (2012) in the Dominican Republic, Cerro Negro (2013) in Argentina, Cochenour (2014) in Ontario and, largest of all, Éléonore (2014) in Quebec. Production at Éléonore is slated to begin at 285,000 oz/year, and plans call for an expansion to more than 600,000 oz three years later.

The Éléonore project is located in the James Bay region, about 350 kilometres north of the towns of Matagami and Chibougamau, Quebec, in the northeast part of the Opinaca Reservoir. Noranda first explored the area for copper in 1964. When Virginia Gold Mines began in 2001 to probe the area of Ell Lake around the copper showing discovered by Noranda, the junior successfully identified a number of new showings. A year later, Virginia had found several other gold-copper-silver occurrences and continuing work led to an area a few kilometres north of the original copper discovery. Grab and channel sampling returned values of more than 1.0 g/t Au.

Virginia began drilling at the Éléonore project in 2005 on the Roberto zone. The mineralization was traced from surface to a depth of 800 metres. Drilling also discovered mineralization beyond the Roberto Peninsula into the James Bay area and on the north shore of Ell Lake as well as to the south. This early exploration success attracted the interest of Goldcorp, and in 2006 it bought the project from Virginia Gold. The deal was worth US$420 million, and Virginia retained a royalty on production.

Goldcorp immediately went to work exploring the claims. The Éléonore project is known to straddle the contact between the Opinaca and La Grande sub-provinces. The project is hosted in Archaean-age rocks of a volcano-sedimentary greenstone belt.

The company says the Roberto deposit is a clastic sediment hosted, stockwork disseminated gold deposit in an orogenic setting. The deposit has a crescent shape approximately 1.9 km long, the result of folding. Mineralization has been traced to 1,400 metres below the surface and remains open at depth. The gold bearing zones generally have a true thickness of 5.0 to 6.0 metres, but some are as thick as 20 metres. The mineralized zones are folded with increased thicknesses at the hinge. The limbs are relatively straight and continuous.

The Roberto gold deposit includes the Roberto, East Roberto and Zone du Lac lenses under the waters of the Opinaca Reservoir. Proven and probable reserves of 12.48 million tonnes averaging 7.56 g/t Au and containing 3.03 million oz of gold have been discovered (as of Dec. 31, 2011). The measured and indicted resource is 1.36 million tonnes at 10.95 g/t Au and the inferred portion is 12.25 million tonnes at 10.60 g/t Au.

The human resource

The most valuable resource at the Éléonore project is the human resource.

“The Cree are an incredible resource,” general manager Guy Belleau told CMJ. “They are not new to this business because they have experience on the hydro projects nearby. They are very good at equipment operation – it’s almost born into them,” he added.

Belleau appears to be enjoying the work at Éléonore. He finds it “interesting” working with different people from different backgrounds and with different mining expertise. His positive attitude leads the way for many successful aspects of the development.

Since the project lies entirely within Cree territory, Goldcorp and the Cree have created a collaboration agreement for the project. This is not an impact benefit agreement, Belleau said. Rather than one side bestowing a benefit on the other, both sides collaborate to create benefits for all. It is a subtle difference, perhaps, but an important one at Éléonore. A collaboration committee oversees matters concerning the environment, training and hiring as well as business opportunities.

The fly-in/out schedule at Éléonore varies. Most employees work a seven-day or 14-day rotation. They also enjoy four weeks of vacation. “That’s five months’ work for a years’ salary,” exclaimed Belleau.

At the end of July, there were about 550 people at the Éléonore site, and the number is expected to reach 850 in October. Those workers enjoy a comfortable camp, good food and a active social committee. Belleau said there will be an ice rink next winter and depending on its popularity, perhaps an indoor rink as well.

Goldcorp embraces the need for continuous improvement. It takes care to grow people, safety and partnerships. The results of this effort was recognized by the Quebec Mining Association when it awarded the F.J. O’Connell trophy to Éléonore in 2011 to acknowledge the 75% improvement in safety at the site in only one year in the past 2 years.

Education is another of Goldcorp’s core values. The company promotes an ore extraction course at the James Bay School Board, and it hired most of the graduates. Students learn the basics of mining to prepare them for jobs at Éléonore. Next year a mineral processing module is planned. Language lessons will be made available at the mine site, French for Cree speakers and vice versa. Meanwhile the lingua franca at the site is English. The project is a bilingual site

Building the best

Goldcorp launched a $1.4-billion construction program at Éléonore in the fall of 2011 as soon as the necessary permits were received. That monetary commitment comes after the company had already spent $346 million exploring and preparing the site. Development will include an underground mine, mill, permanent camp and infrastructure. The first gold will be poured by the end of 2014.

To facilitate development, the orebody has been divided into two parts: the upper portion between 55 and 650 metres below surface and the lower portion between 650 and 1,130 metres. When gold production begins at the end of 2014, the mining rate will be 3,500 tonnes/day from the upper part. Three years later the rate will double and the gold output rise to 600,000 oz per year as the lower parts of the mine come on-stream.

The initial development calls for a 7-m-diameter, 715-m-deep exploration shaft and a 1,600-m-long ramp to the surface. This shaft was nearing completion when CMJ spoke with Goldcorp in July 2012. It will provide 3,500 t/d hoisting capacity, facilitate further development on the 650 level, and create a platform for underground exploration drilling. Muck or material to be hoisted from below the 650 level will be trucked up to the loading pocket, and when completed the 1,600-metre-long ramp will become the air exhaust. The initial skip capacity will be 10 tonnes.

Sinking has begun on a second shaft, the production shaft, and it will reach a depth of 1,500 metres when complete in 2017. Hoisting capacity will be 7,000-t/d, sufficient for the planned higher mining rate. The exploration shaft will become a ventilation raise at this point, and all hoisting will take place through the production shaft. Fresh air requirements for the mine are conservatively estimated to be 273 m³/s when production begins in 2014.

Mining will proceed with long hole stoping as well as down hole drilling or longitudinal retreat with consolidated backfill. Stope widths will vary between 2.5 and 25 metres and they will be 60 metres long and 30 metres high. Depending on the configuration of the mineralized lenses, transverse stoping may be used where the ore is wider. The equipment fleet has been ordered: Caterpillar 50-t trucks, Atlas Copco drills and McLean Engineering bolters. Backfill will consist of paste fill mixed with crushed waste rock.

Engineering and design is substantially completed for the Éléonore mineral processing plant and foundation work has just started at site. Wha
t is planned is a conventional carbon-in-pulp flowsheet with an initial throughput of 3,500 t/d to be expanded ultimately to 7,000 t/d to match the mining rate. There will be three stages of crushing, followed by grinding and gravity concentration ahead of sulphide flotation. The float concentrate will be reground and leached in cyanide, followed by a CIP circuit and stripping.

The tailings area is designed to manage 26 million tonnes of waste, sufficient for the planned life of the mine. A sulphur dioxide-air cyanide destruction circuit will be included. At the end of the project, reclamation will take place over a two- or three-year period followed by the necessary monitoring activities.

Goldcorp is building considerable infrastructure to support the Éléonore mine and mill. An access road, airstrip, electrical power supply and provision of water are all necessary. All supplies and materials will be transported over the road, but employees will be flown in and out. Electrical power will be supplied by Hydro-Quebec, and the permanent substation at Opinaca is nearing completion.

Water management is a concern as the Roberto deposit is located beneath Opinaca Reservoir. A surface crown pillar of 55 metres will remain unmined to avoid potential inflow problems from the reservoir. The company expects a certain amount of water in the mine due to the presence of open sub-horizontal decompression joints encountered within the upper 150 metres of the mine. The dewatering system will have a capacity of 240 L/s in order to handle the expected inflow.

Beyond lucky

Goldcorp is lucky to own the Éléonore project, but the luck is mostly of its own making. The first step toward success is the project’s location in mining-friendly Quebec. Second is the stellar grade, 7.56 g/t Au in the proven and probable reserves. Third is a massive preproduction capital commitment, $1.4 billion. Fourth is access to development and engineering expertise. And finally is the company’s commitment to produce 600,000 oz per year for the benefit of both the local Cree community and its other stakeholders.

The “luck” for Goldcorp is mostly its own hard work.