Higher Grade Lenses Support Phased Development and Selective Mining Approach at Volta Resources' Kiaka Gold Project
TORONTO, January 10, 2013 /PRNewswire/ --
- Feasibility Study to be based on phased development / selective mining approach -
- Global Measured & Indicated resources increase by 10% to 4,862,000 ounces gold -
Volta Resources Inc. ("Volta Resources" or the "Company") (TSX: VTR) announces an updated NI 43-101 compliant Mineral Resource estimate for the Kiaka Gold Project, located approximately 140km southeast of Ouagadougou in southern Burkina Faso. The updated Mineral Resource estimate has been undertaken by independent SRK Consulting (UK) Limited from Cardiff, with input from Volta's geological team. The update follows completion of an additional 233 holes (38,602m) drilled in Phase 4 at the Kiaka Central Area. Including the Randgold drilling (18 holes) and Volta's drilling phases 1 to 3, the total amount of drilling used for the resource estimates at the Kiaka Central and Kiaka South resource areas now stands at 1,623 holes (237,971m).
Highlights:
- Confirmation of the continuity of higher grade lenses within the Kiaka Main Zone (KMZ), facilitating the definition of discrete lenses (KMZ_Lenses) hosting Measured and Indicated Resources of 41.68 Mt @ 1.52 g/t Au for 2,039,000 ounces of gold and Inferred Resources of 5.51 Mt @ 1.70 g/t Au for 301,000 ounces of gold.
- Surrounding the KMZ_Lenses, the KMZ_Halo hosts additional Measured and Indicated Resources of 83.75 Mt @ 0.77g/t Au for 2,072,000 ounces of gold and Inferred Resources of 9.87 Mt @ 0.73 g/t Au for 231,000 ounces of gold.
- Adjacent to the KMZ_Lenses and KMZ_Halo, the Kiaka Footwall Zone (KFZ), the Kiaka Hangingwall Zone (KHZ) and the Kiaka Upper Block (KUB) (collectively referred to as the Adjacent Zones) add a further 26.00 Mt @ 0.76 g/t Au for 633,000 ounces of gold in the Measured and Indicated categories and 18.28 Mt @ 0.80 g/t Au for 469,000 ounces of gold in the Inferred category.
- The total Kiaka Project, including Kiaka Central and Kiaka South, now contains Measured and Indicated Resources of 153.26 Mt @ 0.99 g/t Au for 4,862,000 ounces of gold and Inferred Resources of 33.74 Mt @ 0.93g/t for 1,006,000 ounces of gold (unchanged). This represents a 10% increase in Measured and Indicated Resources, when comparing both sets of models at a 0.4g/t cut-off.
- The total Kiaka Project has higher grade Measured and Indicated Resources of 29.56 Mt @ 1.51g/t for 1,437,000 ounces of gold occurring within the top 250m of the deposits, sufficient to sustain processing ore at an in situ grade approximately 40% higher than the average grade of the deposits in a 6.0 Mt per annum facility for up to five years.
Kevin Bullock, Volta's President and CEO, commented, "The primary objective of the work leading to this latest Mineral Resource update for the Kiaka Gold Project has been met. We can now confidently define discrete and continuous higher grade KMZ_Lenses within the broader lower grade KMZ envelope in the Kiaka Central Area. This supports and clearly illustrates that it would be practical to selectively mine and process sufficient tonnes of ore at an in situ grade approximately 40% higher than the average grade of the deposit for up to five years, while stockpiling the lower grade ore, thereby supporting a phased development approach for the Kiaka Project. This would entail installing initial processing capacity of 6.0 Mt per annum (significantly lowering CAPEX) for up to five years and scaling up to 12.0 Mt per annum for the remainder of the mine life. The phased development scheme will now be implemented in the current Feasibility Study being carried out for the project."
Mr. Bullock also noted, "We are delighted that the Mineral Resource on the Kiaka project has once again increased. Significantly, the Measured and Indicated Resources now stand at 4.86 Moz of gold, representing a 10% increase, while the Inferred Resources remain unchanged at 1.0 Moz of gold. The Kiaka Gold Project now hosts the largest undeveloped gold deposit in Burkina Faso and one of the largest undeveloped gold deposits in the West African region."
The updated Mineral Resource Statement for the Kiaka Gold Project is presented in Table 1.
Table 1: SRK Kiaka Mineral Resource Estimate Statement Split by Deposit and Zone
as of 8th January 2013 at a 0.4 g/t Au cut-off
Metal Gold
Deposit/Zone Category Tonnes (kt) Gold (g/t) (Koz)
Kiaka Central
KMZ_Lenses Measured 12,664 1.58 643
Indicated 29,015 1.50 1,396
Measured & Indicated 41,679 1.52 2,039
Inferred 5,510 1.70 301
Kiaka Central
KMZ_Halo Measured 21,047 0.79 533
Indicated 62,698 0.76 1,539
Measured & Indicated 83,745 0.77 2,072
Inferred 9,872 0.73 231
Kiaka Central
Adjacent Zones Measured
Indicated 25,995 0.76 633
Measured & Indicated 25,995 0.76 633
Inferred 18,280 0.80 469
Kiaka South Measured
Indicated 1,840 2.00 118
Measured & Indicated 1,840 2.00 118
Inferred 75 1.90 5
TOTAL Kiaka Project Measured 33,711 1.09 1,176
Indicated 119,548 0.96 3,686
Measured & Indicated 153,259 0.99 4,862
Inferred 33,737 0.93 1,006
Notes:
- Mineral Resources have been prepared under the CIM guidelines for reporting of Mineral Resources and Mineral Reserves.
- This Mineral Resource estimate is based on a cut-off grade of 0.4 Au (g/t) within mineralized wireframes, within a conceptual Whittle pit shell based on a gold price of US$1,400 per ounce, marginal operating costs of US$11.89 per tonne for processing and G&A and US$1.58 per tonne for mining (assuming a 12Mtpa CIP operation - as per Pre-feasibility study) and assuming a process recovery of 89.8%.
- In the Kiaka Central Area "KMZ_Lenses" and "KMZ_Halo" represent the high and low grade domains within the KMZ respectively, whilst the "Adjacent Zones" represents KHZ, KFZ and KUB (Kiaka Upper Block) mineralization.
- The Kiaka South Area deposit included in the overall Kiaka Project resource estimate is located less than 700m south of the Kiaka Central Area and the Mineral Resource estimate, restated here, was undertaken and reported in September 2012.
- SRK used a block model with block dimensions of 5 x 20 x 10m into which gold grades have been estimated based on optimised ordinary kriging routines with a search ellipse orientated to follow the strike of each domain.
- Mineral Resources have been classified such that Measured Resources have been defined to areas of infill drilling of better than 25m x 25m, Indicated Resources to 50m x 50m and Inferred Resources to blocks lying outside of Indicated wireframes which still display reasonable strike continuity and dip extension.
- All figures are rounded to reflect the relative accuracy of the estimate. All composites have been capped where appropriate.
- Mineral Resources are not Mineral Reserves and do not necessarily demonstrate economic viability.
- The RC and cored samples were collected at 1m intervals. Dry RC samples were riffle-split to provide 2 kg samples sent to the laboratory. Wet samples were dried in the field, then riffle-split in the same way. The cored portion of the drill holes were sampled at one meter intervals and cut in half using a diamond saw. Half-core is archived at the core storage facility on site while the other half sent to the laboratory.
- Samples associated with this Mineral Resource update were assayed at the ALS Chemex laboratory in Ouagadougou, Burkina Faso. The ALS Minerals quality system complies with the requirements of the international standards ISO 9001:2000 and ISO 17025:2005 and operates in all their laboratory sites. Samples were assayed for gold (fire assay with AAS finish), using the ALS protocol with laboratory code "Au_AA26".
- Volta's QAQC procedures include the insertion of certified standards every 15 samples, field duplicates (in the RC portions) about every 25 and blanks about every 10 samples. SRK has analysed the data generated by the QAQC procedures and deems the data to be acceptable for use in the estimation of Mineral Resource Estimates, to be reported in compliance with CIM "Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines" (CIM Standards).
The KMZ comprises a 100m to 260m wide orebody, extending for over 1,500m along strike and over 500m down dip. The KMZ is readily defined within a 0.3 g/t Au mineralized envelope, corresponding to deformed, altered and north-easterly trending corridor of Birimian meta-sedimentary and meta-volcanic lithologies.
Although it was recognized early on by Volta and SRK that there were higher grade lenses of mineralization within a broad halo of lower grade mineralization within the KMZ, previous resource estimates were based on grade interpolation within the overall broad mineralized envelope. In order to highlight the potential of the higher grade zones, previous resource estimates presented a global breakdown of the KMZ mineral resource as "Mineralized Bands" (>1.0 g/t Au) and "Halo Mineralization" (between 0.6 g/t Au and 1.0 g/t Au).
Additional infill drilling, re-logging , interpretation and modelling of the drilling undertaken since the last Mineral Resource estimate in the Kiaka Central Area has now successfully confirmed the presence of discrete higher grade lenses (KMZ_Lenses) ranging between 5m and 50m wide. These extend with good continuity for 100m to 800m along strike and 50m to 400m down dip. They are surrounded by lower grade mineralization (KMZ_Halo), within the broad KMZ orebody.
The confidence in the current interpretation and model for discrete and continuous KMZ_Lenses surrounded by KMZ_Halo is supported by:
- The KMZ_Lenses are visually recognized in drill core as being associated with a retrograde metamorphic event (appearance of a secondary biotite and garnet replacement by chlorite) associated with more intense deformation, overprinting the prograde metamorphic signature that characterises the KMZ_Halo mineralization.
- The KMZ_Lenses can be traced from hole to hole and section to section so that SRK were able to delineate hard boundaries to constrain them for modelling. This has resulted in a marked improvement in geostatistical domaining, thereby significantly reducing the nugget effect, increasing range in the variograms and overall confidence in the resource estimate.
The nature, scale and continuity of the KMZ_Lenses are such that they would be amenable to selective mining for priority processing, while the KMZ_Halo would be stockpiled for processing later. Overall, there are 29.56 Mt @ 1.51g/t Au for 1,437,000 ounces of gold of higher grade material occurring within the top 250m of the deposits. This could be sufficient to sustain processing ore at an in situ grade approximately 40% higher than the average grade of the deposits utilizing a 6 Mt per annum facility for 5 years.
This is illustrated in the graph below, where block model Measured and Indicated Resource tonnage and grade estimates within the conceptual Kiaka Central and Kiaka South resource pits are shown in 50m incremental elevations below surface for the Kiaka Project.
The previous Mineral Resource, reported on 20th March 2012, for Kiaka Central was based on a 0.6g/t cut-off grade. The Kiaka Prefeasibility Study completed in 2012 utilized a 0.4g/t cut-off grade to define Mineral Reserves for Kiaka Central. Consequently, the current Mineral Resource estimate utilizes a 0.4g/t cut-off grade for Kiaka Central. The previous Mineral Resource for Kiaka South used a 0.4g/t cut-off, so this is unchanged. Therefore, comparing like with like at Kiaka Central, there has been an increase in tonnage (+13%), a decrease in grade (-3%) and an overall increase in ounces (+10%) in the Measured and Indicated Resources at the 0.4g/t cut-off grade.
Table 2 shows the Measured and Indicated and Inferred Resources at incremental cut-off grades from 0.2 g/t Au to 1.4 g/t Au, within the updated geological block model for the Kiaka Central Area.
Table 2: Grade Tonnage Sensitivity Analysis and Comparison for Kiaka Central Area
Between 20 March 2012 and 8 January 2013 Models
Current Mineral Resource Previous Mineral Resource
Estimate Estimate
(8 January 2013) (20 March 2012)
Measured & Measured &
Indicated Inferred Indicated Inferred
Tonnes Au Metal Tonnes Au Metal Tonnes Au Metal Tonnes Au Metal
Cut-off Kt g/t (Koz) Kt g/t (Koz) Kt g/t (Koz) Kt g/t (Koz)
1.40 24,750 1.84 1,462 4,390 2.00 284 17,780 1.78 1,020 4,200 1.80 200
1.20 37,930 1.65 2,012 6,540 1.80 374 32,170 1.56 1,610 7,200 1.60 370
1.00 53,990 1.49 2,578 10,010 1.50 496 55,970 1.36 2,450 13,100 1.40 570
0.80 80,030 1.29 3,325 15,090 1.30 642 86,360 1.20 3,330 21,300 1.20 810
0.70 98,770 1.19 3,776 19,330 1.20 744 102,380 1.13 3,710 25,700 1.10 910
0.60 120,570 1.09 4,230 24,250 1.10 846 117,420 1.07 4,030 30,000 1.00 1,000
0.50 139,960 1.02 4,575 30,060 1.00 949 128,250 1.02 4,220 33,400 1.00 1,070
0.40 151,420 0.97 4,744 33,660 0.90 1,002 134,220 1.00 4,310 35,500 1.00 1,100
0.20 156,610 0.95 4,801 35,470 0.90 1,022 137,480 0.98 4,350 37,300 0.90 1,120
The main focus for the Kiaka Project is now to complete the final Feasibility Study before the end of Q3 2013. The study will be based on a phased development scenario, whereby significantly higher grade ore will be selectively processed (with lower grade ore stockpiled) in a 6.0 Mt per annum plant for five years, scaling up to process 12.0 Mt per annum for the remainder of the Life of Mine. This will considerably reduce initial CAPEX and reduce payback periods.
Additional metallurgical test work including more comminution studies and variability analyses is currently underway. Geotechnical and hydrological studies are well advanced with drilling dedicated to these aspects almost complete. Waste rock characterization studies, including test work for acid rock drainage and metal leaching (ARDML), are underway. Civil geotechnical studies to assess load bearing characteristics for heavy infrastructure and substrate conditions for tailings and rock waste storage sites is almost complete. Baseline studies and an Environmental and Social Impact Assessment undertaken to meet IFC Performance Standards are also close to completion.
Exploration on the Kiaka permit will now focus on testing some of the other regional targets identified by Randgold and Volta in this highly prospective area.
A copy of the full technical report that accompanies the NI 43-101 resource statement will shortly be posted on the Volta Resources website and on SEDAR.
Pursuant to National Instrument 43-101, the qualified person responsible for the technical data provided in this press release is Mr. Ben Parsons, a Senior Consultant (Resource Geology), and a full time employee of SRK Consulting (UK) Ltd. Mr. Parsons is a member of the AusIMM with Chartered Professional status. Mr Parsons has reviewed and approved the contents of this news release.
About Volta Resources:
Volta Resources has a portfolio of quality gold exploration projects in Burkina Faso and Ghana, both mining-friendly West African jurisdictions with proven world-class gold deposits. VTR will focus on fast-tracking its flagship Kiaka Gold Project (NI-43-101 compliant resources include 153.26 Mt @ 0.99 g/t Au for 4,862,000 ounces in the Measured and Indicated categories and 33.74 Mt @ 0.93g/t for 1,006,000 ounces in the Inferred category [Please see current VTR press release including 34.38 million tonnes @ 1.04 g/t Au for 1,145,969 ounces of gold in the Proven category and 91.70 million tonnes @ 0.93 g/t Au for 2,742,353 ounces of gold in the Probable category (Please see VTR press release dated May 3, 2012) towards a development decision, aiming to complete a Feasibility Study in Q3, 2013. Recent acquisition of properties around the Kiaka Gold Project has provided VTR with an extensive ground position along the highly prospective Markoye Fault Corridor in an important emerging gold province.
Forward Looking Information Caution:
This press release presents "forward-looking statements" within the meaning of Canadian securities legislation that involve inherent risks and uncertainties. Forward-looking statements include, but are not limited to, statements with respect to the future price of gold and other minerals and metals, the estimation of mineral reserves and resources, the realization of mineral reserve estimates, the capital expenditures, costs and timing of the resources, the realization of mineral reserve estimates, the capital expenditures, costs and timing of the development of new deposits, success of exploration activities, permitting time lines, currency exchange rate fluctuations, requirements for additional capital, government regulation of mining operations, environmental risks, unanticipated reclamation expenses, title disputes or claims and limitations on insurance coverage. Generally, these forward-looking statements can be identified by the use of forward looking terminology such as "plans", "expects" or "does not expect", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates" or "does not anticipate", or "believes", or variations of such words and phrases or state that certain actions, events or results "may", "could", "would", "might" or "will be taken", "occur" or "be achieved". Forward-looking statements are subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of Volta Resources to be materially different from those expressed or implied by such forward looking statements, including but not limited to: risks related to international operations, risks related to the integration of acquisitions; risks related to joint venture operations; actual results of current exploration activities; actual results of current or future reclamation activities; conclusions of economic evaluations; changes in project parameters as plans continue to be refined; future prices of gold and other minerals and metals; possible variations in ore reserves, grade or recovery rates; failure of equipment or processes to operate as anticipated; accidents, labour disputes and other risks of the mining industry; and delays in obtaining governmental approvals or financing or in the completion of development or construction activities. Although the management and officers of Volta Resources believe that the expectations reflected in such forward-looking statements are based upon reasonable assumptions and have attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. Volta Resources does not undertake to update any forward-looking statements that are incorporated by reference herein, except in accordance with applicable securities laws.
Image with caption: "Kiaka Project M&I Resources by 50m Level Increments (CNW Group/Volta Resources Inc.)". Image available at: http://photos.newswire.ca/images/download/20130110_C5054_PHOTO_EN_22398.jpg
For further information:
please refer to our website http://www.Voltaresources.com or contact:
Kevin Bullock, P.Eng., President & CEO
Tel: +1(416)-867-2299
Fax: +1(416)-867-2298
Email: kbullock@Voltaresources.com
or
Andreas Curkovic, Investor Relations
Tel: +1(416)577-9927
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