Orca Gold Discovers Additional Water Resource and Makes Decision to Proceed to Definitive Feasibility Study Based on Larger 3.4 Mtpa Operation at its Block 14 Gold Project
VANCOUVER, BRITISH COLUMBIA--(Marketwired - May 30, 2017) - Orca Gold Inc. (TSX VENTURE:ORG) ("Orca" or the "Company") is pleased to announce that an extensive airborne geophysical survey carried out to the west of the Company's 70% owned Block 14 Gold Project in the Republic of the Sudan has resulted in the discovery of a new and larger water resource for the Project (Figures 1 and 3).
- Hydrogeological consultant, GCS Water & Environmental Consultants, confirms new aquifer discovery;
- Increased throughput enabled by new water discovery reduces unit process operating cost, leading to a material increase in the "in-pit" resources;
- Orca determines it has sufficient information to proceed immediately to a Definitive Feasibility Study ("DFS") to expedite the Company reaching a development decision;
- Company elects to update its PEA on Block 14 ("Revised PEA"), which at a gold price of US$1,200/oz, with in-pit Indicated resource of 1,928 Koz and Inferred resource of 173 Koz, shows an updated pre-tax NPV7% of US$278.2M and an after-tax NPV7% of US$ 227.7M - a 78% increase from original PEA numbers (See Company news release on July 26, 2017); and
- DFS is scheduled for completion in Q1 2018 and Revised PEA details are provided in this news release.
The Company's hydrogeological consultant, GCS Water & Environmental Consultants ("GCS") of South Africa, have recently confirmed the new water discovery and reported that it has a high probability of supplying the quantity of water required to enable production of 3.4 million tonnes per annum ("Mtpa"). Further, this water has significantly better quality than the saline HA8 aquifer, which will reduce reagent consumption.
The discovery of this water supply has enabled the process plant throughput to be significantly increased thus reducing unit process operating costs. A number of throughput scenarios were evaluated, with 3.4Mtpa showing the best potential economic result with current resources. The reduced process costs have led to a material increase in "in-pit" resources at the Galat Sufar South ("GSS") and Wadi Doum deposits.
Based on the engineering studies completed to date, the Company has determined that it has sufficient information to proceed immediately to a definitive feasibility study, which will expedite reaching a development decision while avoiding a delay and the costs associated with finalizing the previously planned pre-feasibility study. Accordingly, the Company has elected to update its preliminary economic assessment on the Block 14 Project ("Revised PEA") with the new information which has been generated throughout the recent phase of engineering studies, which is reported below.
The Revised PEA demonstrates a strong project at a gold price of US$ 1,200/oz, with in-pit Indicated resources of 1,928 Koz, Inferred resources of 173 Koz, a pre-tax NPV7% of US$ 278.2 million, a pre-tax IRR of 26.5%, an after-tax NPV7% of US$ 227.7 million and after-tax IRR of 23.1%.
The Revised PEA is based on contract mining and a 3.4Mtpa carbon-in-leach ("CIL") processing plant at GSS.
A technical report following the guidelines of the Canadian Securities Administrators' National Instrument 43-101 will be filed on Sedar (www.sedar.com) and on the Company website within 45 days.
Highlights of the Revised PEA on a 100% Basis:
Using a gold price of US$ 1,100/oz for mine design, and US$ 1,200/oz for economic analysis, highlights of the Revised PEA include:
- Pre-tax NPV7% of US$ 278.2 million and an IRR of 26.5%;
- After-tax NPV7% of US$ 227.7 million and an IRR of 23.1%;
- In-pit mineral resources comprising 41.0Mt grading 1.46g/t for 1,928 Koz (+57% from Jul '16 PEA) in the Indicated category and 3.4Mt grading 1.56g/t for 173 Koz (+25% from Jul '16 PEA) in the Inferred category;
- 92% of the in-pit mineral resource is in the Indicated category, the balance of which, 8%, is in Inferred;
- 1,630 Koz of gold produced from Indicated resources and 147 Koz produced from Inferred resources over the life of mine ("LOM");
- Mine life of 13.2 years with average annual LOM production of 135,000 ounces of gold;
- Average annual production in years 1-5 of 146,000 ounces of gold;
- Average gold recovery of 84.5%;
- Cash costs of US$ 701/oz for LOM;
- All-in sustaining costs of US$ 752/oz for LOM;
- Pre-production capital costs of US$ 211 million (including a 25% contingency);
- Sustaining capital costs of US$ 92 million; and
- Payback period of 3.0 years, after-tax, from commencement of production.
|Gold Price (US$/oz)||1,100||1,200||1,300||1,400|
|Silver Price (US$/oz)||15.71||17.14||18.57||20.00|
|Pre-tax NPV7% (US$ millions)||177.0||278.2||379.4||480.7|
|After-tax NPV7% (US$ millions)||141.7||227.7||313.7||399.8|
|Pre-tax IRR (%)||20.2||26.5||32.3||37.6|
|After-tax IRR (%)||17.6||23.1||28.2||32.9|
A summary of the key results from the Revised PEA is provided below in Appendix A with further detail on inputs by discipline in Appendix B.
Proceed to Definitive Feasibility Study - Opportunities to Enhance Value
The Revised PEA has demonstrated a very strong project with further opportunity for improvement. Accordingly, the Board of Orca has approved the decision to complete a DFS on Block 14 focused on optimizing the Project towards a development decision in early 2018.
The DFS will focus on the following material enhancement opportunities:
Resource Expansion and Conversion
The Revised PEA pit optimizations have incorporated the bulk of mineral resources defined to date at both GSS and Wadi Doum. As a result, in a number of areas, the optimized shells are restricted in depth by the base of the Resource Block Model (see figure 2 below).
A drill program will be initiated to upgrade the current in-pit Inferred resources (8%) to the Indicated category and to extend the resource model to depth to allow the pit optimizations to reach their economic depth.
Further Water Expansion
The new aquifer system will be evaluated to establish the potential of increasing water supply to enable production throughput beyond 3.4 Mtpa.
Given the large exploration permit area (2,170km2), prospective geological setting and clear gold endowment as indicated by the large numbers of artisanal miners, exploration will be ramped up at Block 14 during the DFS evaluation.
The last drilling campaign identified high grade plunging structures at both GSS and Wadi Doum (see News Release dated February 2, 2017). Exploration drilling during the DFS review will target these structures to evaluate pit extensions.
Resource definition drilling will also evaluate the Liseiwi high grade prospect, located 15kms to the north of Wadi Doum (see News Release dated February 2, 2017).
Metallurgical testing will be carried out on three samples that characterize the main domains so as to optimise the carbon circuit in conjunction with further variability testing will be carried out on samples from the dominant lithologies.
The DFS is scheduled for completion in Q1 2018.
Commenting on the material change in the scope at Block 14, Rick Clark, CEO and Director, said: "The results of the exciting new water discovery and recent engineering work undertaken at Block 14, have completely changed the scope of the Project. We are very excited about having the ability to reach a 3.4Mtpa throughput, which nearly doubles the 1.8Mtpa capacity contemplated in the July 2016 PEA. The open pit designs are now materially larger and, in fact, at many points bottom on data. The potential of additional mineralization at depth below the current pit designs has been highlighted and a new drilling campaign will be commenced shortly to further increase resources. This development has led to the decision to update the PEA to demonstrate the dramatic increase in the Project's scope and to proceed directly to the preparation of a definitive feasibility study and enable an early production decision in Q1 2018."
Revised PEA Contributors
- Lycopodium Minerals Pty Ltd., Lead Author, Overall Project Design
- Deswik Europe Ltd., Mine Design and Scheduling
- SRK Consulting UK Ltd., Geotechnical Review
- MPR Geological Consultants Pty Ltd., Mineral Resource Estimate
- GCS Water and Environmental Consultants, Hydrogeology
- Mineesia Ltd, Environmental and Social Consultant
- MPH Mineral Consultancy, Metallurgical Oversight
The reader is advised that the Revised PEA summarized in this press release is intended to only provide a high-level review of the Block 14 Project potential and design options. The Revised PEA mine schedule and economic model include the use of Inferred resources. Inferred resources are considered to be too speculative to be used in an economic analysis except as allowed for by Canadian Securities Administrators' National Instrument 43-101 (NI 43-101) in PEA studies. There is no guarantee that Inferred resources can be converted to Indicated or Measured Resources.
The technical contents of this release have been approved by Hugh Stuart, BSc, MSc, a Qualified Person pursuant to NI 43-101. Mr. Stuart is President of the Company and a Chartered Geologist and Fellow of the Geological Society of London. Mr. Stuart has reviewed and validated that the information contained in this release is consistent with that provided by the QPs responsible for the Revised PEA.
About Orca Gold Inc.
Orca Gold Inc. (TSX VENTURE:ORG) is a Canadian resource company focused on exploration opportunities in Africa, where it is currently focused on its 70% owned Block 14 project in the Republic of the Sudan.
On behalf of the Board of Directors:
Richard P. Clark, CEO and Director
Cautionary Statement Regarding Forward-Looking Information
This press release contains forward-looking information and forward-looking statements within the meaning of applicable Canadian securities laws, including statements regarding Orca's (the "Company", the "Corporation", "we" or "our") plans and expectations relating to the Block 14 project ("Block 14") in northern Sudan and the revised Preliminary Economic Assessment (the "Revised PEA") and Definitive Feasibility Study ("DFS") currently being completed and/or conducted by the Corporation. These statements relate to analyses and other information that are based on forecasts of future results, estimates of amounts not yet determinable and assumptions of management. Statements concerning mineral resource estimates may also be deemed to constitute "forward-looking statements" to the extent that they involve estimates of the mineralization that will be encountered if the property is developed. The assumptions, risk and uncertainties outlined below are non-exhaustive. Should one or more of these risks and uncertainties materialize, or should underlying assumptions prove incorrect, actual results, performance or achievements of the Corporation, or industry results, may vary materially from those described in this press release.
Any statements that express or involve discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions or future events or performance (often, but not always, identified by words or phrases such as "expects", "anticipates", "believes", "plans", "projects", "estimates", "assumes", "intends", "strategy", "goals", "objectives", "potential", "possible" or variations thereof or stating that certain actions, events, conditions or results "may", "could", "would", "should", "might" or "will" be taken, occur or be achieved, or the negative of any of these terms and similar expressions) are not statements of historical fact and may be forward-looking statements.
Forward-looking statements and forward-looking information are not guarantees of future performance and are based upon a number of estimates and assumptions of management at the date the statements are made including without limitation, assumptions about the following (the "Forward-Looking Factors"): future prices of gold and other metals; successful exploration, development, and production of Block 14; the timing and completion of the DFS; the timing and likelihood of a production decision; performance of contractual obligations by counterparties; operating conditions; political stability; obtaining governmental approvals and financing on time; financial projections and budgets; obtaining licenses and permits; government regulation of the Corporation's mining activities; environmental risks and expenses; market conditions; the securities market; price volatility of the Corporation's securities; currency exchange rates; foreign mining tax regimes; insurance and uninsured risks; financial projections and results; competition; availability of sufficient capital, infrastructure, equipment and labour; dependence on key personnel; dependence on outside parties; conflicts of interest; litigation; land title issues; local community issues; estimation of mineral resources; realization of mineral resources; timing and amount of estimated future production; the life of Block 14; reclamation obligations; changes in project parameters as plans continue to be evaluated; and anticipated costs and expenditures and our ability to achieve the Corporation's goals. While we consider these assumptions to be reasonable, the assumptions are inherently subject to significant business, social, economic, political, regulatory, competitive and other risks and uncertainties, and contingencies, many of which are based on factors and events that are not within the control of the Corporation and there is no assurance they will prove to be correct.
Forward-looking statements are subject to a variety of known and unknown risks, uncertainties and other factors that could cause actual events or results to differ from those reflected in the forward-looking statements, including, without limitation known and unknown risks, uncertainties and other factors relating to the Forward-Looking Factors above, and those factors disclosed under the heading "Risk Factors" in the Corporation's documents filed from time to time with the securities regulators in the provinces of Canada.
In addition, a number of other factors could cause the actual results, performance or achievements of the Corporation to differ materially from any future results, performance or achievements expressed or implied by the forward-looking information, and there is no assurance that the actual results, performance or achievements of the Corporation will be consistent with them. For further details, reference is made to the risk factors discussed or referred to in the Corporation's annual and interim management's discussion and analyses on file with the Canadian securities regulatory authorities and available electronically on the SEDAR website at www.sedar.com. Although the Corporation has attempted to identify important factors that could cause actual actions, events, results, performance or achievements to differ materially from those described in forward-looking statements and forward-looking information, there may be other factors that cause actions, events, results, performance or achievements not to be as anticipated, estimated or intended. There can be no assurance that forward-looking statements or information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Such forward-looking statements and information are made or given as at the date of this press release and the Corporation disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required under applicable securities law. The reader is cautioned not to place undue reliance on forward-looking statements or forward-looking information.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
To view figures 1-3, please visit the following link: http://media3.marketwire.com/docs/1096014figs.pdf
PEA Summary at a Gold Price of US $1,200/oz*
|Revised PEA May 2017||PEA Jul 2016|
|Indicated Resources Mined (million tonnes)||41.0||25.1|
|Average Grade of Indicated Resources (Au g/t)||1.46||1.52|
|Inferred Resources Mined (million tonnes)||3.4||2.8|
|Average Grade of Inferred Resources (Au g/t)||1.56||1.51|
|Total Waste (million tonnes)||104.4||58.7|
|Gold Contained in Indicated resources ('000 oz)||1,928||1,225|
|Gold Contained in Inferred resources ('000 oz)||173||136|
|Total Gold Recovered from Indicated resources ('000 oz)||1,630||1,053|
|Total Gold Recovered from Inferred resources ('000 oz)||147||117|
|Average Gold Recovery (%)||84.5%||86.1%|
|Total Silver Recovered from Indicated resources ('000 oz)||1,926|
|Total Silver Recovered from Inferred resources ('000 oz)||189|
|Average Annual Gold Production ('000 oz)||135||73|
|Average Annual Silver Production ('000 oz)||160|
|Total Pre-production Capital Cost (US$ Million)||210.6||122.6|
|Total Sustaining Capital (US$ Million)||92.0||31.3|
|Total Life of Mine Capital (US$ Million)||302.7||153.9|
|Total LOM Operating Cash Flow (US$ Million)||880.4||448.0|
|Total LOM Pre-tax Cash Flow (US$ Million)||577.7||462.7|
|Average Annual LOM Pre-Tax Cash Flow (US$ Million)||60.1||28.9|
|LOM Taxes (US$ Million)||80.4||46.0|
|Total LOM After-Tax Cash Flow (US$ Million)||497.4||416.7|
|Average Annual LOM After-Tax Cash Flow (US$ Million)||54.0||26.0|
|Pre-Tax NPV (US$ millions)||278.2||156.3|
|Pre-Tax Payback (years)||2.6||3.3|
|After-Tax NPV (US$ Millions)||227.7||128.2|
|After-Tax Payback (years)||3.0||3.7|
|Cash Cost (US$/oz)||701||778|
|All-in Cash and Sustaining Cost (US$/oz)||752||805|
A PEA is preliminary in nature and there is no certainty that the PEA results can, or will, be realized. Mineral resources do not have demonstrated economic viability, and therefore do not constitute mineral reserves.
Revised PEA Detail
Mineral Resource Estimate
Project Mineral Resource Estimates were updated in February 2017 (News Release February 2, 2017) by independent consultant MPR Geological Consultants of Perth, Western Australia using Multiple Indicator Kriging (MIK), and are shown below at a range of cut off grades.
|Au g/t||Mt||Au g/t||Au koz||Mt||Au g/t||Au koz|
|Galat Sufar South||0.60||54.1||1.29||2,246||18.3||1.2||716|
Notes: Defined under Canadian National Instrument 43-101 ("NI 43-101"), Standards of Disclosure for Mineral Projects. Numbers may not add up due to rounding.
The Mineral Resource has been estimated using the results of 79,815 metres of drilling (6,136m of diamond drilling and 74,505m of reverse circulation drilling) completed between November 2012 and December 2016.
The Mining section of the study has been completed by Deswik Europe. Both GSS and Wadi Doum are amenable to development as open pit (OP) mines as all mineralization commences at surface with limited pre-strip. Mining of the deposit is planned to produce a total of 41.0 Mt of CIL feed from Indicated Resources and 3.4 Mt of feed from Inferred Resources and 104.4 Mt of waste (strip ratio 2.35:1) over a 13.2-year project production life, with 6 months of pre-production waste strip.
Mine planning for Block 14 was conducted using DESWIK software. As derived from a geotechnical assessment completed by SRK Consulting (UK) Ltd, inter-ramp pit slope angles range from 37° in the near surface weathered oxide rock mass to between 58° and 65° in the fresh rock depending on structural geology controls and vertical inter-ramp height.
Pit optimizations were carried out using a gold price of US$1,100/oz and a series of optimized shells generated for each area and preliminary pit design undertaken based on a feed rates of 2.6, 3.0 and 3.4 Mtpa to determine optimal throughput rate. 3.4mtpa showed the highest NPV and was selected for pit design.
Cut off grades (Au g/t) were estimated as follows:
|Material||Main Zone||East Zone||NE Zone||Wadi Doum|
Contract open pit mining costs were derived from first principles based on equipment required and include pit and dump operations, road maintenance, mine supervision and technical services cost. In addition Wadi Doum mining costs include the haulage of material to the process plant.
The average open pit operating cost (US$/t mined) is shown below:
In addition, a transfer cost of $7.74/t will be incurred on material from Wadi Doum.
In compliance with NI 43-101, the revised PEA study is based on Indicated and Inferred Mineral Resources. The table below shows the breakdown of material by resource type within the pit designs:
|Deposit||Indicated Resources||Inferred Resources||% Indicated|
|Mt||Au g/t||Koz||Mt||Au g/t||Koz|
|Galat Sufar South||38.7||1.40||1,740||3.0||1.5||141||93%|
Note: Numbers may not add up due to rounding
Based on the results of metallurgical test work by SGS Mineral Services in Vancouver, Lycopodium has defined a process flowsheet which is based on a processing rate of 3.4 Mtpa.
The treatment plant design incorporates single stage primary crushing with a jaw crusher to produce a crushed product which flows to a crushed material surge bin. Surge bin overflow is conveyed to an emergency stockpile. Material from the emergency stockpile is reclaimed by front end loader (FEL) to feed the mill during periods when primary crushing is off-line. The milling circuit is configured as a two-stage circuit with a SAG mill and ball mill (SAB), both with the ability to operate in closed circuit. Milled material undergoes pre-leach thickening to increase the slurry density feeding the leach and carbon in leach (CIL) circuit to minimise tankage, improve slurry mixing characteristics, and reduce overall reagent consumption. The leach step consists of a leach and CIL circuit incorporating three dedicated leach tanks ahead of six stages of CIL for gold adsorption. Gold desorption and recovery is provided via a split AARL elution circuit, electrowinning, mercury retorting and gold smelting to recover gold from the loaded carbon to produce doré, and safely remove mercury. Tailings are thickened to recover and recycle process water from the CIL tailings with the tailings pumped to the tailings storage facility (TSF).
A summary of the ultimate recoveries used in the study is summarized below:
|Grind (µm)||Au Recovery||Ag Recovery|
|East Zone Oxide||53||89.7%||32%|
|Main Zone Oxide||53||91.8%||35%|
|NE Zone Oxide||53||91.8%||33%|
|East Zone Transition||75||84.9%||69%|
|Main Zone Transition||75||81.3%||47%|
|NE Zone Transition||75||83.1%||58%|
|East Zone Fresh||94||81.0%||68%|
|Main Zone Fresh||94||83.7%||59%|
|NE Zone Fresh||94||82.4%||63%|
|Wadi Doum Fresh||53||85.7%||57%|
Process Cost Summary
Process operating costs have been developed for each material type. In general, costs have been built up from first principle estimates, with quotations obtained for major reagents and consumables and consumption rates based on metallurgical test work, calculations or modeling. Minor reagents, laboratory, expatriate labour rates and a number of G&A costs have been sourced from the Lycopodium database. The process operating cost includes all direct costs to produce gold bullion for the Project.
Power will be generated on site using diesel generators under a Build Own Operate ("BOO") contract. A cost of $0.50/l has been used in determining the power costs.
The table below details the Process costs used in the study which are inclusive of general and administrative costs. Process costs (including G&A) are presented on the basis of fixed, $18.0M/yr and variable costs. Costs are based on pricing as at 2Q 2017 and have an accuracy of +/- 30%.
|Main Zone Fresh||US$ 10.65 / t|
|Main Zone Transition||US$ 10.33 / t|
|Main Zone Oxide||US$ 9.09 / t|
|East Zone Fresh||US$ 10.56 / t|
|East Zone Transition||US$ 11.55 / t|
|East Zone Oxide||US$ 10.15 / t|
|NE Zone Oxide||US$ 8.54 / t|
|Wadi Doum Fresh||US$ 12.10 / t|
Capital Cost Summary
A capital cost estimate was developed to an accuracy level range of +/- 30% to cover engineering, procurement, construction, and start-up of the mine and processing facilities, as well as the ongoing sustaining capital costs. The capital cost estimates were developed for a conventional open pit mine, CIL process plant and supporting infrastructure for an operation capable of treating 3.4 million tonnes of material per annum. For the purpose of this PEA, power supply via a third-party Build Own Operate Transfer and a contract mining scenario have been assumed.
The estimate covers the direct costs of purchasing and constructing the CIL facility and infrastructure components of the project and an allowance for mining related infrastructure.
Indirect costs associated with the design, construction and commissioning of the new facilities, owner's costs, and contingencies have also been estimated, based on percentages of the direct capital cost estimate. Risk amounts are specifically excluded from this estimate. A breakdown of the capital cost estimates is shown below:
|Pre-production Capex||US$ '000|
|Construction Sub Total||169,514|
|Sustaining Capex||US$ '000|
Work undertaken by GCS during the course of the pre-feasibility study showed that the HA8 water resource had limited expansion potential.
As a result, SkyTEM Surveys of Denmark, an airborne geophysical contractor specialising in water exploration were contracted to fly a 5,000km electromagnetic survey with the aim of expanding the HA8 discovery and investigating a new area to the west of Block 14 (Area 5) where two old production wells are located (see Figure 3).
The survey in Area 5 returned positive results over a large area and has now been followed up with drilling. The aquifer, which is hosted within the Nubian Sandstone Formation (NSF), has been intersected in 6 boreholes between 58m and 90m from surface. Pump test results have shown consistent aquifer yields and GCS are comfortable that the aquifer has a high probability to sustain the output required for a 3.4Mtpa process plant.
The bore field will be connected to plant site at GSS by an 80km HDPE pipeline.
In 2014, Orca initiated comprehensive environmental baseline studies under the supervision of Mineesia Ltd., a UK consultancy with experience of remote desert projects. Terms of Reference for the Environmental Impact Assessment were submitted to the Government in 2015 as part of the Environmental Protection and Management Plan.
The site is located in a remote location, with no human settlements nearby (the closest town, Abu Hamad is 200km to the south). There are numerous artisanal and small-scale mining operations in the vicinity of the Project, although these are mostly illegal and unlicensed. No other sources of industry are present in the area. There are no permanent surface watercourses within the Project area and there is no evidence of significant groundwater in the crystalline basement. Soils have little to no agricultural potential. Vegetation is sparse and fauna, including domestic livestock, is limited due to the scarcity of permanent water sources.