Seafield Reports Updated Metallurgical Results and High Gold Recovery Rates at Miraflores, Colombia
TORONTO, ONTARIO -- (Marketwire) -- 02/15/13 -- Seafield Resources Ltd. ("Seafield" or "the Company") (TSX VENTURE: SFF) is pleased to report preliminary metallurgical test results of an extensive metallurgical development program for its gold-silver Miraflores Deposit, Quinchia, Colombia, presently underway at Inspectorate Exploration and Mining Services Ltd. ("Inspectorate"), located in Richmond, BC, Canada. This study program was designed and is being supervised by SRK Consulting in Denver ("SRK") on behalf of Seafield.
Highlights:
-- All test composite samples evaluated were highly amenable to gold
recovery by a process flow sheet using conventional gravity
concentration followed by gold flotation from the gravity tailings;
-- All test composite samples, ground to a nominal P80 of 106mm, contained
significant amounts of coarse gold amenable to gravity concentration.
Gold recoveries of 52 to 65% were obtained in gravity cleaner
concentrates containing between 382 - 1,271 g/t Au;
-- Gravity concentration followed by gold rougher flotation from gravity
tailings resulted in gold recoveries ranging from 94 to 98%;
-- The next phase of the metallurgical program will investigate process
parameters required to cyanide leach the gold contained in the flotation
concentrates.
"We are delighted to confirm the high gold recovery rates for all major geo-metallurgical units in the Miraflores deposit and are confident these materials can be treated efficiently by the flow sheets evaluated with the present metallurgical development program," commented Dave Prins, Seafield's Chief Operating Officer. "As this study advances, the results obtained will provide the data required for the design of a potential commercial processing facility."
Sample Characterization
Three composite samples were prepared from multiple quarter-core drill hole samples representing the major geo-metallurgical units in the mineable areas of the deposit. Based on the mining plans developed in our earlier PEA study (see press release dated, April 23, 2012) two mining operations, an open pit and an underground mine were designed. In the open pit mine, the major geo-metallurgical units were determined to be White and Green breccias with a minor contribution of Red and Grey breccias and Basalt. In the underground mine the major geo-metallurgical unit are the White breccias, with minor amounts of Green breccias. The minor geo-metallurgical units are not included in the master composite samples and will be used only for process variability studies.
For the purposes of this study, the major geo-metallurgical units of both open pit and underground mines were studied in detail. Considering that the Miraflores deposit is essentially a large mineralized breccia containing multiple high-grade veins, the samples selected to be part of the master composites consisted of long mineralized quarter core intervals of varying grades, which included vein intervals.
To prepare the composites for the open pit mine, the drill holes and intervals selected crossed the proposed minable material blocks from the PEA mining plan. Similarly, for the underground mine, the drill holes and intervals selected were within the material blocks that could be mined as indicated by the PEA mining plan.
Table 1 below, shows the characterization of these sample composites.
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TABLE 1. Characterization of Composite Samples
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MATERIAL # of
MINE TYPE Drill holes WEIGHT AVERAGE GRADE
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Au, Ag,
Kg g/mt g/mt
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UNDERGROUND White Bx 11 408 1.71(1) 1.5
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OPEN PIT White Bx 9 516 0.75(2) 3.7
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Green Bx 10 572 1.64(2) 6.9
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Source: Inspectorate
(1)Average of triplicate splits (3 assays)
(2)Average of duplicate assay of triplicate splits (6 assays)
Metallurgical Test Results
Initial test work was conducted on the three composite samples representing the major geo-metallurgical units at a target P80 grind of 74 microns. After gravity separation, the gravity tails were subjected to rougher gold flotation using different reagent schemes. Once optimum process parameters for flotation were established, tests were conducted to evaluate gold recovery versus grind size for each master composite.
Table 2 shows the effect of grind size on gold recovery for the major geo-metallurgical units. An economic analysis will determine the optimum grind size.
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TABLE 2. Effect of Grind Size on Gold Recovery
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OPEN PIT UNDERGROUND
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WHITE BRECCIA GREEN BRECCIA WHITE BRECCIA
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P80 Au P80 Au P80 Au
microns Recovery % microns Recovery % microns Recovery %
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186 97 182 92.5 188 98.7
149 89.7 145 94.4 164 98.6
125 92.2 123 96.9 127 97.1
110 98.8 99 94.1 104 98.5
74 97.5 70 99 70 99
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Work in Progress
Future work to be completed is outlined below, with the metallurgical test work program scheduled for completion in Q2 2013:
-- Completion of Master Composite Studies:
-- Mineralogical evaluations
-- Gravity concentration-rougher flotation-cleaner flotation studies
-- Locked-cycle flotation tests
-- Concentrate cyanide leaching
-- Cyanide detoxification studies
-- Sedimentation studies
-- Tailings geochemistry evaluation
-- Comminution Testing (Master Composites and Variability Composites)
-- Bond ball mill work index
-- SAG Mill Comminution (SMC) tests
-- Abrasion work index
-- Metallurgical testing on variability composites
Seafield's Miraflores Deposit is situated in the Company's 100%-owned, 6,757-hectare, Quinchia Gold Project. Miraflores is a low sulphidation epithermal gold deposit located in Colombia's mineral-prolific Mid-Cauca gold belt. The mineralization is located in a hydrothermal breccia pipe with free gold associated with cement materials (the matrix) and high grade structures where gold is associated with zinc, lead, copper and iron. At surface, the breccia pipe has a drill-tested diameter of 250 metres by 280 metres. The breccia pipe widens and remains open at depth with a drill-tested vertical extent of 600 metres.
Review by Qualified Person
The results of the Company's metallurgical testing program presented in this news release have been reviewed and verified by Eric Olin, MSc, MBA, RM-SME, Principal Process Metallurgist of SRK in Denver, Colorado. Mr. Olin has over 30 years experience in the minerals industry with extensive consulting, plant operations, process development, project management and research & development experience with base metals, precious metals, ferrous metals and industrial minerals.
About Seafield Resources Ltd.
Seafield Resources Ltd. (TSX VENTURE: SFF) is a mineral exploration company currently focused on advancing its Miraflores Gold Deposit towards feasibility level. Seafield's 6,757-hectare Quinchia Gold Project is located in the Department of Risaralda of Colombia. SRK Consulting Inc's (Denver) Preliminary Economic Assessment on the Miraflores Deposit indicates robust economics with a pre-tax internal rate of return of 50% and a pre-tax net present value (8%) of $249M (see corporate PEA presentation at http://bit.ly/MFeL7q). Miraflores currently has a NI 43-101 compliant Measured and Indicated resource estimate of 1,925,542 ounces gold at 0.8 g/t Au (77Mt at a cut-off of 0.3 g/t Au) and an Inferred resource estimate of 103,043 ounces gold at 0.6 g/t Au (5.5Mt at a cut-off of 0.3 g/t Au). Additionally, the Company has a NI 43-101 compliant resource estimate for its Dosquebradas Deposit, also part of the Quinchia Gold Project, with an Inferred resource estimate totalling 920,772 ounces gold at 0.5 g/t Au (57Mt at a cut-off of 0.3 g/t Au). Seafield Resources Ltd. trades its shares on the Toronto Venture Exchange (TSX-V) under the symbol SFF and in the United States using CUSIP 81173R101. For more details on the Company, please visit www.sffresources.com.
Forward-Looking Statement
This news release includes certain "forward-looking statements" within the meaning of that phrase under Canadian securities laws. Without limitation, statements regarding potential mineralization and resources, exploration results, and future plans and objectives of the Company are forward looking statements that involve various degrees of risk. Forward-looking statements reflect management's current views with respect to possible future events and conditions and, by their nature, are based on management's beliefs and assumptions and subject to known and unknown risks and uncertainties, both general and specific to the Company. Although the Company believes the expectations expressed in such forward-looking statements are reasonable, such statements are not guarantees of future performance and actual results or developments may differ materially from those in our forward-looking statements. The following are important factors that could cause the Company's actual results to differ materially from those expressed or implied by such forward looking statements: changes in the world wide price of commodities, general market conditions, risks inherent in exploration, risks associated with development, construction and mining operations, the uncertainty of future profitability and the uncertainty of access to additional capital. Additional information regarding the material factors and assumptions that were applied in making these forward looking statements as well as the various risks and uncertainties we face are described in greater detail in the "Risk Factors" section of our annual and interim Management's Discussion and Analysis of our financial results and other continuous disclosure documents and financial statements we file with the Canadian securities regulatory authorities which are available at www.sedar.com. The Company undertakes no obligation to update this forward-looking information except as required by applicable law. The Company relies on litigation protection for forward-looking statements.
Neither 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.
Contacts:
Seafield Resources Ltd.
David MacMillan
Investor Relations
(416) 361-3434 ext. 202
dmacmillan@sffresources.com
www.sffresources.com