Sep 13 2016
Luna Gold Corp., ("Luna" or the "Company"), is pleased to announce the results of its pre-feasibility study (PFS) prepared in accordance with National Instrument 43-101 (NI-43-101) on its 100% owned Aurizona gold mine (Project) located in northeastern Brazil. The PFS indicates that the Project represents a robust, rapid pay-back, high margin, simple open pit mining project that demonstrates strong returns in the current gold price environment. The financial results of the study yielded an after-tax internal rate of return (IRR) of 34% and a net present value (NPV) of $201 million based on a base case gold price of $1,250 per ounce and a discount rate of 5% (at $1,350 per ounce gold price the IRR is 41% and the NPV5% is $256 million).
With the completion of the PFS, Luna has restated its Proven and Probable Mineral Reserves for the mine at 969,000 ounces of gold contained in 18.6 million tonnes of ore at a diluted grade of 1.62 grams per tonne (g/t) of gold. This has been underpinned by the re-evaluation of the Mineral Resources at Aurizona following the comprehensive 2015 drilling program, which included 15,000 metres of oriented core drilling, 3,000 metres of RC drilling and re-logging of historic core. The extensive technical work provides a strong basis for the new project and processing flow sheet to treat all ore types. As a result, the combined Measured and Indicated Mineral Resources are now at 1.6 million ounces of gold (inclusive of reserves) contained in 29.9 million tonnes at a grade of 1.67 g/t gold.
Initial capital expenditure to fund construction and commissioning is estimated at a modest $146 million due to Aurizona's ability to leverage significant existing infrastructure in place at the brownfields mine site. Life of mine (LOM) sustaining capital is estimated to be $47 million. The all-in sustaining cost (AISC) is projected to be an attractive $708 per ounce over the life of the project and the current Mineral Reserves support a 6.5 year mine life with excellent potential to increase the Mineral Reserves and Resources and extend the mine life. Procurement and construction of the new components and equipment for the restart of the mine are expected to take 18 months.
Christian Milau, CEO, stated, "We are very pleased with the results of this pre-feasibility which provides a solid basis for continuing with the development and implementation of the Aurizona Mine restart plan. With so much of the necessary infrastructure already in place, Aurizona compares favourably to its peers given the initial capital is significantly less than many similar size projects. Further, exploration to date has outlined numerous high-priority, near-mine exploration targets that highlight the potential to significantly extend the mine life."
David Laing, COO, added, "This pre-feasibility study is a culmination of the extensive work done thus far to get the Aurizona Mine back into production in the second half of 2018. The 2015 drilling and metallurgical testwork programs have been instrumental in developing a strong technical foundation and have tremendously advanced our understanding of the geology, alteration, weathering, structure and, metallurgy, and their controls on gold mineralization, processing and recoveries."
The Aurizona Mine comprises a brownfield open pit mine, gold processing plant and property containing the Piaba and Boa Esperança gold deposits and numerous exploration targets located in Maranhão State in northeastern Brazil. This PFS provides the compilation of the engineering and geological studies that incorporated the results from the extensive drilling program conducted in 2015.
Pre-Feasibility Study Highlights:
- 1.60 M ounces of gold (Measured and Indicated Mineral Resources) contained in 29.9 M tonnes at an average diluted grade of 1.67 g/t of gold.
- 969,000 ounces of gold (Proven and Probable Mineral Reserves) contained in 18.6 M tonnes with an average diluted grade of 1.62 g/t gold
- Metallurgical recovery of 91%
- Process plant capacity of 8,000 tonnes per day
- Average production of approximately 150,000 ounces of gold per annum for years 1 to 5
- Overall strip ratio of 6.2:1 (tonnes, waste:ore)
- New crushing circuit comprising an apron feeder, primary jaw crusher and related material handling equipment
- New grinding circuit comprising an 8.5 m diameter SAG mill, a 5.5 m diameter ball mill and pebble crusher
- Conventional gravity concentration with an intensive leach reactor and a leach/carbon in pulp (CIP) cyanidation process in plant for the gravity tailings
- Improved gold recovery system through the addition of three leach tanks
- Improvement to the carbon desorption and recovery circuits through
- Pressurized elution vessel
- Completing and commissioning the carbon regeneration kiln
- Improving the electrical and instrumentation systems
- Raises to the tailings dam
- Modest initial capital of $146 million including new mine fleet
- Sustaining capital of $47 million
- Operating costs of $2.05 per tonne mined, $11.00 per tonne processed and G&A (including selling costs) of $3.50 per tonne processed
- Cash operating costs of $606 per ounce
- Low AISC of $708 per ounce
PFS Economic Assumptions
- Gold price of $1,250 per ounce was used for the base case
- Brazilian Real to US dollar exchange rate of 3.5:1
PFS Project Economics
- After tax NPV5% of $201 million and pre-tax NPV5% of $220 million at $1,250 per ounce gold price (at $1,350 per ounce gold price the NPV's are $256 million and $286 million, respectively)
- IRR of 34% on an after-tax basis and 35% on a pre-tax basis at $1,250 per ounce gold price (at $1,350 per ounce gold price the IRR's are 41% and 43%, respectively)
- $347 million in after-tax cash flow during the first five years of production
- Total project cash flow of $296 million (NPV at 0% discount rate), including construction capex
- EBITDA of $558 million for the life of mine
- Payback of 2.6 years
The following table illustrates the sensitivity of the Project to fluctuations in the gold price and foreign exchange.
Aurizona Mine Sensitivity to Gold Price
Aurizona Mine Sensitivity to Brazilian Real:US Dollar Exchange Rate
The following tables detail the capital and operating costs.
Aurizona Mine Capital Cost Estimate
(Including duties and taxes)
Aurizona Mine Operating Cost Estimate
(Including non-recoverable taxes and excluding recoverable taxes)
Mineral Resources and Reserves
In Q4 2015, the Company completed a 15,000 metre oriented core drill program. Analysis of the data derived from the program has resulted in a substantially improved understanding of the Piaba gold deposit geology, geochemistry, and structure, which is now reflected in the updated Mineral Resource and Reserve statements which follow.
Combined Piaba and Boa Esperança Mineral Resource Statement
Notes: This Mineral Resource estimate has an effective date of April 30, 2016 and was prepared by Mr. Brett R. Marsh, C.P.G. of Phoenix Geoscience, LLC, who is a qualified person under NI 43-101. Mineral Resources are inclusive of Mineral Reserves. Mineral Resources that are not included within the Mineral Reserves do not have demonstrated economic viability. Mineral Resources are stated at the following cutoff grades for open pit: Piaba: Laterite and Saprolite at 0.30 g/t Au; Hard Saprolite/Transition/Fresh Rock at 0.40 g/t Au. Piaba: Outside open pit at 2.0 g/t Au. Boa Esperança cutoff grade: 0.44 g/t Au. Piaba topography is current as of February 28, 2015. Tonnes are rounded to the nearest 1,000; ounces are rounded to the nearest 100. Small tonnage and grade differences may be found due to rounding. The Mineral Resource and Mineral Reserve estimates contained herein may be subject to legal, political, environmental or other risks that could materially affect the potential development of such Mineral Resources.
Aurizona Mine Proven and Probable Mineral Reserve Statement
Notes: This Mineral Reserve estimate has an effective date of June 21, 2016 and is based on the Mineral Resource estimate effective on April 30, 2016. The Mineral Reserve calculation was completed under the supervision of Gordon Zurowski, P.Eng of AGP Mining Consultants Inc., who is a Qualified Person as defined under NI 43-101. Mineral Reserves are stated within the final design pit based on a $1,104 per ounce gold price pit shell with a $1,200 per ounce gold price for revenue. The cutoff grade was 0.38 g/t Au for all pit areas. The mining cost averaged $2.32 per tonne mined, processing averages $11.30 per tonne milled and G&A was $2.84 per tonne milled. The process recovery averaged 90.5%. The exchange rate assumption applied was R$3.50 equal to $1.00. The PFS scope only considers the Piaba and Boa Esperança open pit mineralized zones. The Mineral Resource and Mineral Reserve estimates contained herein may be subject to legal, political, environmental or other risks that could materially affect the potential development of such Mineral Resources.
Mineral resources that are not included within the Mineral Reserves do not have demonstrated economic viability.
Mine
The mine plan is based on the current resource model and calls for conventional truck and excavator/front end loader open pit mine operations with a stripping ratio of 6.2:1. The new mine plan continues mining in the existing Piaba open pit, deepening the pit and mining harder rock types which will be amenable to treatment in the upgraded processing plant following the installation of the new comminution circuit.
The mine plan was developed to provide a practical mining sequence, while optimizing net present value, and incorporates the early mining of the Boa Esperança pit which on completion will provide water storage capacity as part of the overall site water management plan. Primary mining activities will take place in the Piaba pit.
Mining will be performed by a combination of Aurizona owned and operated equipment and a mining contractor. Aurizona performed mining will focus primarily on hard saprolite/transition and fresh rock and will be performed by a combination of hydraulic excavators and front end loaders and 63 tonne rigid frame trucks, and will be responsible for almost all ore mining activities as well as a base load of waste mining. The mining contractor will focus primarily on the laterite and saprolite waste mining, with the exception of the Boa Esperança pit, which will include ore. The overall approach will serve to keep the Aurizona executed mining rate relatively constant while optimizing capital expenditures on mining equipment. Drilling and blasting of all hard saprolite/transition and fresh rock will be performed by Aurizona; explosives will be purchased on a down-hole basis from a local supplier. Hard rock accounts for 57% of the Mineral Reserves, while saprolite and transition account for 14% and 29% respectively. The mine schedule delivers 18.6 Mt of ore grading 1.62 g/t Au to the mill over the Life-of-Mine (LOM). Waste tonnage totalling 115.7 Mt will be stockpiled in the north, west, south and east waste rock management areas. The LOM production schedule is presented in the following table.
Aurizona Mine Production Schedule
Mining costs, including the mining contractor charges, are estimated to average $2.00 per tonne mined (excluding taxes) over the current LOM.
There is excellent potential to extend the mine life beyond the initial approximately seven years through exploration on the Piaba trend.
Process Plant
The PFS is based on a process plant capable of treating 8,000 tonnes per day through a combination of conventional gravity concentration and leach/CIP cyanidation processes. The design includes a new comminution circuit which will treat all ore type which comprises a primary jaw crusher, SAG (semi-autogenous grinding) mill, ball mill and pebble crusher. The plan also calls for the completion of several process items that were partially installed during the Phase 1 Expansion of 2014 as well as the repairs and improvements to the existing process plant equipment. Installations will include an intensive leach reactor, a hybrid leach/CIP circuit, pressurized elution, carbon regeneration kiln, upgraded hydro-cyclones, the addition of three leach tanks, and completion of partly-installed high rate thickeners. Improvements and refurbishments to the existing process plant include upgrades to the cyanide destruct and tailings deposition system, gravity recovery circuit, electrical distribution system, instrumentation and controls and plant infrastructure. The planned daily throughput maximizes the use of power available to the project available on the Maranhão State power grid after certain substation improvements.
Average cost to process a tonne of ore is expected to be $10.96 per tonne milled over the current LOM. The operating cost varies dependent on the blend of the three main ore types being processed. The variations are power and steel consumption, cyanide and lime. The main reasons for the variations are differences in hardness, abrasiveness, mineralogy and alkalinity.
Metallurgy
The Piaba and Boa Esperança ore bodies consist of saprolite, transition and fresh rock mineralization. The average Axb values were moderate for the transition ore and very competent for the fresh rock. The transition ore average Axb (impact breakage test result) value of 67 was the 27th percentile of the Orway Mineral Consultants (OMC) database. The fresh rock average Axb value of 28.1 was the 94th percentile of the OMC database. The Bond ball mill work indices (BWi) values ranged from very soft (saprolite) to moderate (fresh rock). The saprolite, transition and fresh rock average BWi values of 5.7, 8.1, and 13.6 places the respective ore in the 2nd, 7th and 32nd percentile for grinding amenability.
The process gold recovery design criteria are based on test work conducted from 2011 through to 2016. The test work has been consistent across the various campaigns and laboratories and showed that gold is readily recovered using conventional cyanide leaching with a retention time of 30 hours. Utilizing a P80 100 µm grind size, gold recoveries between 90% and 97% are expected over the LOM. Design recoveries by process and metallurgical domain are presented in the table below:
Aurizona Gold Recoveries
Leaching reagent consumptions ranges from 0.45 to 0.54 kg/t NaCN and 0.80 to 3.71 kg/t CaO.
The orebody is known to contain carbonaceous material which has been tested. The impact on gold recovery is negligible and not considered material. Similarly, the orebody contains small amounts of arsenopyrite, which are considered to have a minor impact on gold recoveries, reducing the LOM recoveries by approximately 2%. Further work is planned to confirm this value.
Tailings Storage Facility
The project will expand the capacity of the existing Vené tailings storage facility (TSF) in three lifts. The first will be carried out before the restart of the process plant, followed by the two additional lifts approximately every two years thereafter. Construction of a new tailings facility, Zé Bolacha, will start in year four. Both facilities are designed as unlined, compacted earth fill structures with sand chimneys and blanket drains. Following cyanide neutralization, tailings slurries (approximately 40% solids) will be pumped via pipeline to the TSF and spigoted from the dam crest to maintain the water pool towards the rear of the reservoir area and away from the main dam embankment. Water will be recovered and pumped back to the process plant or the Boa Esperança pit reservoir.
Infrastructure
Given the brownfields nature of the Aurizona Mine, the project is endowed with considerable infrastructure, which includes the back end of the plant, offices, warehouses, laboratories, communications and camp. It also benefits from the existing road access from Belem (440 km) and São Luis (320 km), as well as the electrical grid via the Maranhão power utility, CEMAR.
The site-wide water balance work has indicated that the operation has access to sufficient fresh water for un-interrupted operations in a variety of conditions, ranging from extreme drought to extreme flooding.
Environmental
The Project has three environmental conditions of note.
Small-scale artisanal operations (garimpos) exist in the region and have impacted the vegetation, the soil and the hydrologic system in areas near the Project. To date, it does not appear that these projects utilize mercury to extract gold as these operations typically utilize hand-held metal detectors.
The mine has excess water during the wet season, and must provide proper sedimentation to all mine runoff and process water prior to discharge in the surrounding estuaries.
In January 2016, mild Acid Rock Drainage (ARD) conditions developed on site, which appear to be related to the oxidation of the exposed transition material. The transition material comprises 16% of the mine waste and is potentially acid generating (PAG). In contrast, fresh waste rock is 22% of waste tonnage and appears to be acid consuming. In order to better mitigate ARD risk, an enhanced static and kinetic geochemical testing program was started, and an ARD management program has been implemented to manage current conditions, along with a LOM mitigation plan.
Labour
There is abundant labour in the region, and as a prior operator, the project has access to previously trained local and regional staff.
Permitting
The Aurizona Mine was placed on care and maintenance in the third quarter of 2015. The Company has worked diligently to maintain its licenses and permits in compliance with regulatory requirements. The Company's team in Brazil is in constant and direct contact with all required regulatory authorities to monitor our licenses and permits. The Company has requested that the existing License to Operate (LO), be amended to cover changes to the operating parameters, including the increased plant throughput to 8,000tpd and raises to the Vené TSF. Receipt of this amendment is anticipated in mid-2017 and is not expected to impact the construction schedule.
Technical Report Preparation
The PFS has been prepared by several independent Qualified Persons (QPs) and was consolidated by Lycopodium Minerals Canada Limited. The Mineral Resources and the new geological block model were prepared by Phoenix Geoscience LLC. The Mineral Reserves, mine plan and mining sections of the study were prepared by AGP Mining Consultants Inc., and the geotechnical and environmental matters were led by Global Resource Engineering Ltd. The financial model and tax analysis was prepared by L&M Assessoria. The Company expects to file a technical report prepared in accordance with NI 43-101 on SEDAR at www.sedar.com within 45 days of the date of this release.
Taxes and Tax Credits
The financial model incorporates recovery of $27 million of certain Brazilian value-added type taxes, primarily ICMS and PIS/COFINS. The financial model also incorporates assumptions about the expansion and extension of income tax deductions made available under a government economic stimulus program (the "SUDENE") to companies for industrial projects developed in northeastern Brazil. The SUDENE deductions total $64 million. The assumed income tax rate is 15.25%
Management Information Systems
The project will benefit from the fully functional mine accounting and management information systems, including warehousing, purchasing and payroll.
Planned Feasibility Study
The PFS recommends that the project continue to the next phase with the preparation of a feasibility study, and contains a number of recommendations including, but not limited to, work programs which address the following areas and continue to de-risk the project:
- Further infill drilling on the Boa Esperança deposit
- Condemnation drilling west and north of the Boa Esperança
- Additional geotechnical field work to support the recommended pit slopes, waste storage facilities, and tailings dam raises
- Additional metallurgical testwork to confirm preliminary indications that the presence of Arsenic does not materially impact gold recovery in the process plant
- Additional geochemical characterization to mitigate ARD risk.
- Other programs associated with site drainage and surface water management.
A $2.4 million program has been outlined by Luna to address these items with the objective of issuing a feasibility study by end of Q1 2017 and targeting first gold pour in the second half of 2018.
Value Enhancement
As the Project continues toward the production phase, all efforts will be expended to identify and quantify ways to enhance project value and reduce costs. These activities will be on-going at all levels of the operation including exploration to determine the optionality of following trends over the brownfields areas contiguous to the Piaba Pit and elsewhere over the Project areas.
Share Consolidation
Luna Gold also announces today a proposed consolidation of its share capital on the basis of up to ten (10) existing common shares for one (1) new common share. Currently, a total of 326,793,355 common shares in the capital of the Company are issued and outstanding. Accordingly, if put into effect on the basis of ten (10) existing common shares for one (1) new common share, a total of 32,679,335 common shares in the capital of the Company would be issued and outstanding following the Share Consolidation, assuming no other change in the issued capital.
The Share Consolidation will affect all of the Company's stock options and warrants issued and outstanding at the effective date. At the time of the Share Consolidation, the number, exchange basis or exercise price of all stock options and warrants issued and outstanding will be adjusted to reflect the ten-for-one Share Consolidation. The actual adjustment will be made by the Company in consultation with its advisors.
The Board of Directors of the Company will ask the shareholders of the Company to approve the Share Consolidation at a Special Meeting of shareholders to be held on Monday, October 31, 2016.
The Share Consolidation is subject to shareholder approval and acceptance of the Toronto Stock Exchange.