Improving a Project from PEA to FS

The alternatives for the Whabouchi project were analyzed in two phases. First, in the preliminary economic assessment (PEA) released in February 2013, a range of variants were considered by Nemaska Lithium and which were further described in the Environmental and Social Impact Assessment (ESIA) filed in April 2013.

In light of the comments and concerns that emerged from the consultations held after the ESIA was filed, the project was subsequently re-assessed within the framework of the feasibility study (FS) with a view to optimizing it from a technical, economic, as well as an environmental and social standpoint. The alternatives examined in the feasibility study included the waste rock and tailings pile, and the location of the sedimentation basins and related final effluents, i.e., the project components of greatest concern for Cree stakeholders.

In this new assessment, Nemaska Lithium considered it paramount to:

  • Reduce the amount of mine infrastructure to be built;
  • Concentrate infrastructure near the ore deposit;
  • Minimize the ecological footprint of the project.

In addition, the analysis of the options for the location of mine infrastructure was guided by a series of factors and criteria as noted below:

  • Much of the planned infrastructure depends on the actual location of the ore deposit (which cannot be moved);
  • The presence of many natural and physical constraints, such as Mountain Lake and Spodumene Lake, the Route du Nord and the 735-kV power line;
  • Many other constraints such as, the topography, surface deposits, hydrography, wetlands, wildlife habitats, use of the territory, water supply, resources and potential archeological areas, and certain health- and safety-related elements, etc.;
  • Technical considerations such as the need for safe slopes in the pit design, and minimum safe distances from blasting areas.

EATo address these concerns, it was decided to completely review the siting of all stockpiles, basins and effluents to ensure they were located far from Mountain Lake. At the same time, other changes were made to the project so as to reduce wetland losses; have only one final effluent as defined by Quebec’s Directive 019; reduce the visual impact associated with the waste rock and tailings pile for land users and neighbouring Cree camps; and avoid any deviation of the existing Route du Nord and maintain its current location.Also, despite the fact that the operating mine life increased from 19 to 26 years from the PEA to the ESIA, Nemaska Lithium and its consultants were still able to reduce footprint of the project. The 11% reduction in pit footprint is essentially based on the fact that underground operations were recommended as of Year 21, and the infrastructure required for underground operations will be located entirely within the boundaries of the open pit.

The initial water management plan devised in the PEA and presented in the ESIA (April 2013) was significantly revised and optimized in the feasibility study. The new version of the plan was developed with a view to preventing and minimizing potential impacts on surface and ground water quality and quantity in the project study area.

Among other changes, there is now only one final effluent as per Quebec’s Directive 019 at the outlet of the mine water basin located southwest of the open pit. The water in this basin will be discharged into Mountain Lake via a subaqueous pipeline. Effluent quality and dispersion modelling was completed by WSP Canada Inc. and Roche Ltd. to ensure the proposed plan is adequate and enables full compliance with applicable provincial and federal water quality standards.

Seven sedimentation basins will be set up in the main low points around the two waste rock and tailings cells, as well as around the garage area, the plant, the temporary ore stockpile and the overburden pile. Runoff from these areas will be collected in ditches built around the periphery of the facilities. This runoff will ultimately be directed toward a final retention basin located southwest of the waste rock and tailings pile.

A pipeline will move water from the outflow of this retention basin to the mine water basin located southwest of the open pit. This basin will also collect water generated as part of pit dewatering activities, that is, groundwater that infiltrates the pit as well as waters running off the pit area. The final effluent from the mine water basin, once fully complying with all applicable quality criteria, will be directed via a surface pipeline to Mountain Lake. To minimize the visual impact of the pipeline for Mountain Lake users, it will be buried as of about 100 m from the shoreline. The discharge point will be located in an area and at a depth that will promote dispersion of the effluent. Modelling of the effluent plume was initially carried out in the fall 2014 and is still being updated to confirm the precise position of the discharge site and potential effluent dispersion.

Process water will be entirely recycled or recirculated and therefore will not be released into the environment, primarily because of the recommended tailings management method which calls for the production of dewatered tailings (9% moisture content; a.k.a. dry stacking or filter-pressed). A minimal back-up source of water (fresh water supply well) will be required for the operation of the concentrator (mixing reagents and pump imperviousness).

Runoff water from outside the mine site will be diverted to avoid any contact with mine installations. Runoff elsewhere on the mine site (roads) will be collected and discharged into sedimentation basins for treatment of suspended matter before being released into the environment.

Design criteria set out in Quebec’s Directive 019 for the drainage network associated with accumulation areas that have no dykes shall be met, if not exceeded, in all cases. This means runoff collection networks (ditches and basins) were designed to have the capacity to handle 1,000-year flood events, if not more in some cases. Such capacity includes, in all cases, a minimum 1-m freeboard to be maintained for all basins.

With regards to tailings management, best economically and technically available technologies have been integrated to project design so that filter-pressed tailings will be produced at the mine site to be co-disposed with waste rocks on a dedicate pile. The aforementioned method is associated to several advantages, as outlined in the Report on Mount Polley Tailings Storage Facility Breach issued in January 2015 by the Mount Polley Independent Expert Engineering Investigation and Review Panel. Indeed, the production of filter-pressed tailings, or dry stacking, especially when co-disposed with waste rocks, is commonly associated with the following technical and environmental advantages which easily counterbalance the typically higher costs of producing such type of tailings:

  • High process water reuse rate in the concentrator;
  • High reagents reuse rate in the ore process;
  • Significant reduction of the risks of leaks or spills (ex. damaged pipes, through dykes) and therefore of risk of environmental contamination;
  • No more dyke required to store tailings and therefore no risk of dam failure;
  • Filtered tailings can be compacted and/or leveled once disposed on the dedicated pile, enabling an easier co-disposal with waste rocks;
  • Filtered tailings are geotechnically stable and can be stockpiled at greater height and with steeper slopes than conventional tailings, therefore reducing the surface footprint of the dedicated pile;
  • Filtered tailings can be progressively revegetated, i.e. before mine closure, as the mine is still in operation;
  • Significant reduction of the surface footprint of the whole project by enabling the co-disposal of tailings and waste rocks.

The changes made to the project as part of the feasibility study enable a significant reduction of the physical footprint of the Whabouchi Project. The surface area of terrestrial habitats and wetlands that will be impacted by various mine developments and hence lost during the construction phase of the project will total 147.89 and 7.38 ha respectively. The vast majority, i.e. more than 80%, of the total impacted terrestrial area, is occupied by recent burns.

Changes made to the layout of mine infrastructure in the feasibility study made it possible to avoid the loss of 53.51 ha of terrestrial and wetland environments. The direct impact of the project on these environments was therefore reduced by 25%. Given the abundance and regional character of the forest stands surveyed in the study area, the losses incurred will not have a significant impact on the specific richness of the local or regional vegetation.

In addition, a number of mitigation measures were selected to minimize the impact of the project on these environments, including fully delimiting those areas where mining activities are permitted and reducing site clearing operations. The entire site will be revegetated as part of mine closure so that habitats for native species will quickly be re-established on the site. To ensure the effectiveness of revegetation activities, an agronomic monitoring program will be put in place.

Finally, it is important to note that under the Act Respecting Compensation Measures for the Carrying out of Projects Affecting Wetlands or Bodies of Water, wetland losses associated with the Whabouchi project shall be compensated through a plan approved by the MDDELCC. Measures have in fact been taken to ensure this plan includes funding for a scientific research program aimed at acquiring knowledge on the ecological (environmental and social) value of the boreal peatlands in the James Bay Lowlands. In addition to biogeochemical and hydrological components, the research program will include a component on knowledge of traditional Cree practices with respect to such wetlands. Nemaska Lithium will act as the lead industrial partner for this research project, in collaboration with Stornoway Diamond and other partners. The research program is still being elaborated as of today.

The changes made to the project as part of the feasibility study mean that henceforth no mine infrastructure will be located in a watercourse or lake that is considered to be a fish habitat. The work to optimize the project and reduce the mine footprint has meant that only Lake 29 will be destroyed by the development of the waste rock and tailings pile. It should also be noted that surveys conducted showed that this lake is not a fish habitat. The loss of an estimated 0.16 ha of water environment however will be compensated in a wetland and water body compensation program under Quebec’s Act Respecting Compensation Measures for the Carrying out of Projects Affecting Wetlands or Bodies of Water.

The management of runoff and site drainage during the construction and operation phases is likely to result in localized and temporary changes to some lakes and rivers (and consequently the use of fish habitat). These impacts will be in addition to those caused by the dewatering of the open pit during the mine operation phase. The lakes and watercourses that are the most likely to be affected by the joint reduction in surface and groundwater inflows are lakes 2, 27 and 28, and creeks C and F. The decrease in surface water inflows will have more impact than the drawdown of the water table, which is considered to be limited. To determine the surface area of fish habitat that potentially dries out, additional surveys were carried out in the summer 2014. These data were also used in modelling the effluent dispersion plume in Mountain Lake.

It is therefore anticipated that the Whabouchi project could cause indirect fish habitat losses along shorelines primarily in lakes 2, 27 and 28 and creeks C and F. The change in water levels is estimated to be limited and would fall within the natural drawdown zone in the lakes. Those fish habitats that may be affected by lower water levels hold water for only very short periods and are partially dry under natural conditions.

Modelling of the mine effluent plume dispersion confirmed the limited potential impact of the effluent on water quality in this lake. In addition, to validate the impact assessment, a water quality monitoring program for the lake and the effluent is planned, in compliance with applicable provincial and federal standards.

To offset fish habitat losses caused by the Whabouchi project, a preliminary habitat compensation program was developed. This preliminary compensation program needs to be analyzed by and discussed with stakeholders, including the Cree Nation of Nemaska, the Cree Nation Government and the provincial and federal authorities, so as to meet the applicable requirements and the objectives of the Canadian Fisheries Act. The final program will specify proposed intervention measures (developing spawning grounds, and creating shelter and feeding areas), the habitat area to be developed, target species, and proposed sites, etc.

The majority of the impacts attributable to the Whabouchi project will be within trapline R20, and more specifically in the southwest sector of that trapline (which includes the northern part of Mountain Lake where the Bible Camp and a number of other Nemaska Cree camps are located).

To reduce the impacts of the project on land and resource use, various mitigation measures will be put in place including the following:

  • To avoid disturbing the spring goose hunt, all extraction activities at the mine (blasting, and placing material on the tailings pile) will be suspended during the spring goose hunt, locally known as the Goose Break;
  • Crees who use the land will be kept informed of the mine’s schedule of activities to help them manage or reorganize their harvesting activities;
  • Cree users of the territory and community members will be informed of environmental monitoring results and will be regularly consulted for their observations and recommendations regarding the presence of wildlife on the affected territory;
  • Working with the R20 tallyman, a beaver and black bear trapping program will be put in place if necessary prior to the start of construction work;
  • Clearing by-products in every project phase will be made available to Cree users or to the community of Nemaska;
  • Protection measures will be taken to ensure the safety of Cree users along snowmobile routes that may be affected by mine activities. Adequate signalling will be installed as needed at crossings near the mine site;
  • Continue discussions regarding the Bible Camp and Cree camps whose use will be affected by mine activities;
  • If possible, organize activities at the waste rock and tailings pile in such a way as to minimize noise at the Bible Camp;
  • Prohibit mine employees from harvesting wildlife (hunting, fishing and trapping) on mine property;
  • Implement an equipment maintenance plan to prevent equipment from deteriorating and increasing its noise levels; and undertaking noisy operations during daytime hours;
  • Ensure heavy machinery, vehicles and equipment are in proper working order (adequate maintenance); enforce speed limit of 30 km/h on project site; use MDDELCC-authorized dust-control agents or water on service roads (including ramps) as required; and progressively reclaim the waste rock and tailings pile.

Land and resource use will be monitored during the construction and operation phases of the Whabouchi project. In compliance with the Chinuchi Agreement, monitoring will focus on the use of trapline R20 and its resources by the tallymen and main trapline users.

The objective of the Whabouchi mine project is to produce a spodumene concentrate that will be transported to a hydrometallurgical plant located in Southern Quebec for the production of lithium hydroxide and lithium carbonate.

The option of using pipelines to transport the concentrate was eliminated from the outset since this concentrate will have a solid content greater than 95% and could not therefore be pumped. The only other options were truck or train transport. The mine site is adjacent to the Route du Nord, a provincial route that is already used for transporting goods and heavy machinery. The road, which is the only land route between this part of Northern Quebec and Chibougamau, joins Route 167 about 15 km north of Chibougamau. The railway line in Northern Quebec (CFILNQ) operated by Canadian National (CN) ends in Chibougamau.

To minimize the ecological footprint of the Whabouchi project, along with infrastructure costs and environmental and social impacts, it was decided to use existing infrastructure that is operational provided it has the capacity to meet project requirements. Building a rail line between Chibougamau and the mine site was quickly eliminated given the high construction costs along with the fact that the small quantity of material to be transported (extraction of 3,000 tpd of ore to produce 595 tpd of spodumene concentrate) would not justify the environmental and social impacts. It was therefore decided to transport the concentrate to Chibougamau by truck along the existing Route du Nord, without having to make any changes to the road.

Two options were considered regarding truck transport, specifically using 38-tonne semi-trailers that would make 16 trips per day, or 100-tonne trucks that would make 6 trips per day. To avoid increasing average daily traffic along with the percentage of heavy trucks on the Route du Nord, the decision was made to go with 100-tonne trucks.

Since this type of truck is not authorized to travel on Route 167, nor in urbanized areas of Chibougamau, the concentrate will be transported by truck along Route du Nord and then along forest road R-1008 to the transhipment center project by the City of Chibougamau. At this location, Chibougamau contemplates the implementation of a regional transhipment center which Nemaska Lithium intends to use. Unloading the trucks from the mine and loading Canadian National (CN) railcars will be carried out at this site.

From exploration to operations to closure, the mining industry is facing a growing number of challenges. The issue of mine rehabilitation and reclamation is one such challenge that has in recent years been the subject of increased attention from legislators, authorities as well as the general public.

Since 1995, the Quebec Mining Act required mining companies to submit a Mine Rehabilitation and Closure Plan (or Restoration Plan) for approval to the Department of Energy and Natural Resources (MERN). New legislation has strengthened this requirement to ensure mineral development projects are environmentally and socially acceptable.

In August 2013, the Government of Quebec adopted a modified version of the Regulation Respecting Mineral Substances other than Petroleum, Natural Gas and Brine. This regulation increases the financial guarantee from 70% to 100% of the cost of restoring the entire mine site (not just the cost of restoring accumulation areas) and establishes a revised timetable for submitting payments, which are to be made in three annual instalments, including 50% to be paid within 90 days of receipt of plan approval, and 25% in each of the subsequent second and third instalments. Moreover, under the Act to Amend the Mining Act adopted in December 2013, restoration plans must now be approved before mining leases are granted and therefore any mining operations be initiated.

Nemaska Lithium has submitted to the MERN in 2015 its Mine Closure and Rehabilitation Plan. It was developed by Roche Ltd, Consulting Group, in line with Quebec’s Guidelines for Preparing a Mining Site Rehabilitation Plan and General Mining Site Rehabilitation Requirements, which specifies requirements for site rehabilitation, the contents of restoration plans, and the approval process.

The main objectives of the plan are to restore the site to a satisfactory condition by eliminating unacceptable health hazards and ensuring public safety; limiting the production and movement of substances that could harm the receiving environment as well as the need for long-term maintenance and monitoring; restoring the site to a condition which is visually acceptable to the community; and reclaiming infrastructure sites for future use.