VANCOUVER, BRITISH COLUMBIA--(Marketwired - June 27, 2013) - Magellan Minerals Ltd. (TSX VENTURE:MNM)(OTCQX:MAGNF) ("Magellan") is pleased to report that metallurgical results from the first phase of testing for the Feasibility Study on the Coringa Project have been received.
Highlights include:-
- 96.7% - 99.0% overall gold recoveries from samples ground to a P80 of 75 microns using a combination of initial gravity separation followed by carbon-in-leach cyanidation for 48 hours
- 92.3% - 96.7% gold recoveries from sulphide samples at the relatively coarse grind of P80 of 150 microns, after cyanidation for 48 hours
- Recoveries of 51.1% to 65.2% via gravity methods at a grind a P80 of 150 microns. Previously reported recoveries via gravity testwork indicated recoveries in the range of 40-50% at P80 of 150 microns
Whole ore carbon in leach gold recoveries of greater than 95% after 24 hours of leaching were achieved from two composite samples; the first sample representing 243.64kg of sulphide ore from the Galena, Mae de Leite and Serra zones, and the second representing 280.74kg of sulphide ore from the Meio and Come Quieto zones. These results are as good or better than the previous results obtained after 48 hours of leaching. In addition, gold recovery by gravity concentration resulted in recoveries greater than 50%. Additional testing is on-going now to optimize the flowsheet. The test results are an important step in advancing the design of the processing plant.
| Grind size (P80 microns) | ||||
| 150 | 106 | 75 | ||
| Gravity recovery (7L/m fluidization) | ||||
| Composite 1 | 65.2% | 63.6% | 62.6% | |
| Composite 2 | 51.1% | 47.5% | 47.4% | |
| Leach recovery (after 48 hours with activated carbon) | ||||
| Composite 1 | 96.7% | 98.0% | 99.0% | |
| Composite 2 | 92.3% | 94.8% | 96.7% | |
Note: These recoveries do not include additional losses incurred during elution and electrowinning
For the gravity test work, a total of 4kg of each sample were milled for three different grind sizes (P80 = 150,106 and 75 microns) and passed through a Knelson lab concentrator MD-3 using three different fluidization water flow rates (3,0 - 5,0 - 7,0 L/m). At each fluidization water flow rate, one concentrate was taken from each sample. Each concentrate was then dried, weighed and leached using cyanide concentrations of 20.000 mg/L (rolling bottle).
For the whole ore leach tests with activated carbon, a 3kg sample from each composite was taken and sub-divided into six sub-samples of 500g. Each sub-sample was then placed in a bottle under the following conditions; activated carbon, 18 g of carbon/l, pH adjusted to 10-11 (with hydrated lime), 40% solids, sampling (Au, CNFREE, pH) at 2, 6, 8, 12, 24, 48 hour intervals, and an initial cyanide concentration of 1000 g/t.
The test work was carried out by Testwork Desenvolvimento de Processo Ltda in Nova Lima, Brazil from March to June of 2013. Although preliminary, the results are as good or better than previous test results reported in the December 2012 Preliminary Economic Assessment Technical Report.
Commenting on the results, Alan Carter, President & CEO stated "these new metallurgical test results on larger samples of ore have been conducted as part of the feasibility study at Coringa, and confirm our earlier work which indicates gold recoveries in excess of 95% from a combination of gravity separation and leaching. The metallurgical work is an important step forward in advancing the Coringa feasibility study."
This press release was reviewed by John Kiernan, P.Eng., Magellan's VP Project Development and a qualified person in compliance with National Instrument 43-101.
Magellan Minerals (TSX VENTURE:MNM)(OTCQX:MAGNF) is a TSX Venture Exchange listed exploration and development company with two advanced gold properties in the Tapajos Province of northern Brazil. The Coringa project is currently the subject of a Feasibility Study and contains Measured and Indicated resources of 561,000oz of gold (3.2Mt @ 5.5g/t gold) and Inferred resources of 534,000oz of gold (5.5Mt @ 3.0g/t gold). The Cuiu Cuiu project contains 100,000oz of gold in the Indicated category (3.4Mt @ 1.0g/t gold) and 1,200,000oz of gold in the Inferred category (31Mt @ 1.2g/t gold).
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.
This news release contains forward-looking statements. Forward-looking statements address future events and conditions and therefore involve inherent risks and uncertainties. Actual results may differ materially from those currently anticipated in such statements. Particular risks applicable to this press release include risks associated with achieving production on the project within the parameters identified in the economic assessment, the ability of the project to generate significant cash flow to the company and earnings to the shareholders of the company. These statements are subject to risks due to regulatory, technical, economic and other factors. In addition there is no guarantee that additional exploration work will result in significant increases to resource estimates. The reader is referred to the Company's most recent annual and interim Management's Discussion and Analysis for a more complete discussion of such risk factors and their potential effects, copies of which may be accessed through SEDAR at http://www.sedar.com
News release #2013-7
