Preliminary Economic Assessment
In January 2014 the Company released a PEA Study with respect to Hardrock Project.
Highlights of the 2014 PEA Studies (all currency amounts in Canadian dollars unless otherwise stated) include:
Hardrock Project Estimates
- Average annual gold production during the first 8 years of 253,100 ounces with life of mine "LOM" (15 years) annual production of 202,700 ounces (including low-grade stockpiles).
- Average grade over the first 8 years of 1.50 grams per tonne gold "g/t Au" with a LOM average grade of 1.18 g/t Au (including low-grade stockpiles).
- Initial processing of 10,000 tonnes per day "tpd", expanding to 18,000 tpd in Year 3.
- Pre-production capital costs of $410.6 million including $83 million for contingency.
- Pre-tax net present value "NPV" (at a 5% discount rate) of $519 million at US$1250 gold.
- Pre-tax internal rate of return "IRR" of 23.0% and a 3.5 year payback at US$1250 gold.
The Hardrock PEA study assumes that open pit mining only will be used for resource extraction. This was judged to be the quickest and least risky proposition of converting resource to reserves and execution. The mineral resource estimate, as reported on October 29, 2013, excluded the impact of mining dilution, which is the incidence of waste rock extracted together with mineralized material.
For the PEA, open pit mining dilution is calculated as 5% at 0 g/t gold. Open pit resources have been calculated assuming a material loss of 5%. With an open pit cut-off grade of 0.35 g/t gold, the resulting tonnages and grades for the open pit conceptual mine plan, including planned low-grade stockpiles, is shown in Table 1.
Table 1 Diluted Open Pit Mineral Resources Used in Hardrock PEA Study
|Cut-off Category||Resource Category||Tonnes (Mt)||Gold (Au) Grade (g/t)||Au Ounces (Moz)|
|Open Pit (O/P)||Indicated||64.663||1.18||2.454|
The Hardrock PEA is preliminary in nature and it includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that the Hardrock PEA will be realized. Mineral resources are not mineral reserves and do not have demonstrated economic viability. All figures are rounded to reflect the relative accuracy of the estimate. All assays have been capped where appropriate.
The Hardrock PEA assumes the processing of an average 10,000 tonnes per day of material during the first two (2) years of production, followed by an expansion to 18,000 tonnes per day in Year 3 for the remainder of the mine life (13 years), from a combination of direct process open pit material and stockpile reclaiming operations.
The open pit mine and stockpiling reclaim plan is a 15-year plan that utilizes a stockpile strategy to maximize grade to the mill and mines to an ultimate depth of 460 metres below surface.
The Hardrock open pit is designed as a conventional surface mining operation blasting 30 million tonnes of material per year in the first two years of operations and 45 million tonnes per year thereafter. The primary equipment fleet would consist of up to two 27 m3 hydraulic shovels, one 15 m3 hydraulic shovel, one 18 m3 wheel loader, 150 and 250 tonne-class haul trucks, and a fleet of support equipment. Production drilling will be carried out by up to five diesel-powered track-mounted units on 203 mm holes. Operating bench heights of 10 metres have been assumed for mining operations.
Over the life of the open pit, a total of 391 million tonnes of waste rock and overburden material would be moved. During the pre-production period, 1.6 million tonnes of overburden and waste rock would be removed as part of development work. Waste rock-to-mill-feed operating strip ratio are expected to average 5.37 during mining operations and 4.38 over the life of the mine (including low grade stockpiles and overburden).
Open pit mining operating costs include mine supervision, drilling, blasting, loading, hauling, services, dumps, roads and maintenance costs. These costs were evaluated using data from other similar projects and from budget quotes provided by suppliers. An extra 38% was added to the salaries to account for benefits, and depending on the job, bonuses were also included. A maximum of 207 direct positions have been estimated for mining requirements based on past experience and industry averages.
Metallurgy & Processing
Recent metallurgical testing conducted during 2013 on open-pit resource material served as a basis for the milling flowsheet developed by BBA. The highlights of the process flowsheet include:
- Primary crushing and two-stage grinding;
- Gravity recovery;
- Whole-rock carbon-in-leach circuit;
- Cyanide destruction;
- Carbon stripping, electro-winning, and smelting to produce gold doré.
The estimated mill operating expenses were based on available reagent consumptions and additions from testwork, local manpower costs, and industry standards where applicable. A roster total of 62 workers (increasing to 71 with the 18,000 tpd expansion) is established for the milling and assay lab requirements based on past experience and industry averages. An electrical power cost of $0.08/kWh is assumed for this study.
The Hardrock Project benefits from world-class infrastructure, services and available labour within several communities in the immediate area. The project site is located only 260 km from Thunder Bay, Ontario (population 108,000), a few kilometres south of Geraldton, Ontario (population 1,893) and at 32 kilometres west of Longlac (population 1,388) all within the Municipality of Greenstone, and the Long Lac #58/Ginoogaming (population 600) First Nation Reserves. It resides along the Trans-Canada Highway and is accessible year-round. The Trans-Canada natural gas pipeline passes close to the site. Finally, some infrastructure will need to be relocated to accommodate the project.
Infrastructure is anticipated to include:
- Plant site and haul roads, gate house, parking, bus station and weigh station;
- Administration building, including all services; engineering, geology, administration, environment, health and safety, mine supervision, fire fighting, emergency office (ERT) and human resources;
- 9 door open pit garage and warehouse;
- Assay lab;
- Electrical surface infrastructure;
- Emulsion plant;
- Fuel storage facilities;
- Fresh water supply and fire protection;
- Dewatering and water contact treatment plant;
- Sewage treatment;
- One tailings pond;
- Power to the project supplied by an existing 115-kV transmission line connected to the provincial grid;
Premier is a proud member of the local Greenstone communities, participating in a number of local events, initiatives and boards. The company's community relations office provides members of the public with the opportunity to engage with the company directly, outside of regular communications, mailings, and open houses. Additionally, Premier also has a site office, multiple staff residence properties and extensive local staff.
Premier regularly engages with local Aboriginal communities, and is proud of the relationship that has and continues to develop. Premier utilizes personnel from local Aboriginal communities on the Hardrock Project, such as representatives from each community as part of the environmental monitoring team.
A formal environmental baseline work program has been ongoing since 2011. Since 2013, Premier began more extensive regional monitoring and assessment work that was undertaken to gain a thorough understanding of the current environmental conditions in the region, including the impacts of the Trans-Canada Highway on this former industrial site.
Key economic performance metrics are summarized in Table 9 on both a pre-tax and after-tax basis. A range of gold prices (US$) are shown for sensitivity purposes only. At US$1250 gold price, the Hardrock open pit project has a pre-tax IRR of 23.0% (19.% after-tax), a pre-tax NPV (discounted at 5%) of some $519 million ($359 million after-tax) and a payback of 3.5 years on a pre-tax basis (3.9 years on an after-tax basis).
Table 10 is a spider graph representing the sensitivity of the change of any one variable over a range of percentage difference versus the base case. Of the five variables measured, changes in grade and gold price have the greatest impact on the NPV (pre-tax) of the project.
Opportunities & Risks
Opportunities to improve Hardrock Project economics include the following:
- The Hardrock PEA is based on the August 9, 2013 mineral resource cut-off date and does not include subsequent infill drilling of some 45,000 metres completed to the end of 2013.
- The next resource update is planned for Q2/2014 and will include a more refined underground voids model which could potentially contribute resource tonnes and ounces previously included at zero grade.
- Infill assays of previously unsampled drill core will improve the confidence of the grade estimate in some areas.
- Refining the litho-structural model by incorporating information gleaned from historic drilling (not assay data) will improve confidence in the model constraints.
- Follow-up drilling in the North Wall area could bring additional mineral resources into the optimized pit.
- Completing an underground study to further enhance project economics.
- Potential improvement in metallurgical recovery
- Management of construction/engineering and procurement schedules, costs, and cost containment.
- Operating risks related to recruitment and training of open-pit workforce.
- Currency risk relating to equipment purchases denominated in US currency.
- Permitting risk
- Complete infill drill program for revised mineral resource estimate in 2014.
- Proceed with baseline environmental work for completion by summer 2014 (ongoing monitoring work forecasted for life of mine.
- Optimization work (testing and engineering) for minimizing capital and operating costs.
- Detailed engineering work for final feasibility.
- Renewed focus on regional targets and new deposit discovery.
- Complete the baseline environmental and optimization work (testing and engineering) necessary to ensure a successful environmental assessment process.
- Submission of a project description is anticipated in spring 2014 to federal and provincial governments to begin the formal environmental assessment processes. This will comprise baseline environmental information collected over past years, comprises formal public and aboriginal consultation periods and helps ensure a mine design that avoids and mitigates environmental impacts.
Preliminary Economic Assessment
Historic Mine Photos