Aureus Mining Inc. - Excellent metallurgical recoveries for Ndablama and Weaju
TORONTO, Dec. 10, 2013 /CNW/ - Aureus Mining Inc. (TSX: AUE) (AIM: AUE) ("Aureus" or the "Company") is pleased to announce preliminary metallurgical results for its Ndablama and Weaju Gold projects ("Ndablama", "Weaju"), located within the Northern Block of the Company's 100% owned Bea Mountain Mining licence in Liberia, and within 25 to 30 kms of the New Liberty gold project. These results follow the announcement by the Company on 11 November 2013 of maiden resources for Ndablama and Weaju, together exceeding a total of 600,000 ounces of gold. The metallurgical testwork was performed by ALS laboratories in Perth, Australia under the supervision of DRA Mineral Projects (Pty) Ltd ("DRA").
- Preliminary testwork was conducted on bulk composite samples from Ndablama and Weaju drill cores to test the metallurgical response of the oxide and sulphide material to a gravity / leach treatment route
- For Ndablama, cyanide leach tests for both the oxide and sulphide material returned overall gold recoveries of respectively 92% and 94%. A 70% gravity recovery was obtained for the sulphide material
- For Weaju, gravity / cyanide leach testwork for the oxide material returned recoveries between 92% and 98% across all cyanidation tests conducted. For the sulphide material, recoveries between 89% and 93%, depending on the head grade, were obtained across all gravity / cyanidation tests conducted. Gravity recoveries for both the oxide and sulphide material returned values ranging from 39% to 48%
- Both the Ndablama and Weaju ores are deemed to be amenable to gravity recovery and direct cyanidation using a Carbon in Leach process. Further detailed gravity / leach testwork will be undertaken in the future to assess if there is any variability in metallurgical response across these mineralised bodies
- Further exploration drilling is currently in progress at Ndablama
Commenting on the metallurgical results, David Reading, President and Chief Executive Officer of Aureus Mining Inc., said:
"The results from the metallurgical tests from Ndablama and Weaju further demonstrate the quality of Aureus' assets. With the New Liberty gold project rapidly progressing towards production, and with the potential for significant upside including the Ndablama and Weaju deposits, Liberia is demonstrating its credentials as the new gold district in West Africa."
DRA scoped and managed scouting testwork on the Ndablama orebody at the request of the Company. Testwork was conducted at ALS Laboratories in Perth, Australia (ALS), and limited to assessing the amenability of the ore to cyanidation.
Representative samples of oxide and sulphide material were selected by the Company geologists and dispatched to ALS. Bulk composites of oxide and sulphide material were constructed giving average head grades of 0.91g/t and 2.21g/t of gold for the oxide and sulphide material respectively.
Two leach tests incorporating gravity recovery stages were conducted on each bulk composite. Both the oxide and sulphide material are deemed to be amenable to cyanidation with average residue grades of 0.08g/t and 0.14g/t of gold obtained for oxide and sulphide material respectively. This returned overall gold recoveries ranging between 92% and 94% for the oxide and sulphide material, from head grades of 0.91g/t and 2.21g/t of gold respectively. Recoveries may vary according to head grades and further variability leaches will be conducted in the future to assess gold recovery variation across the Ndablama deposit.
Additionally, the sulphide material in particular returned a gravity recovery of 70%, which could be exploited to positive effect in the process plant design.
As the testwork scoped and managed by DRA was preliminary, only aspects of the gravity / leach circuit regarded as key to the success of the process were investigated. These included the grindability of the sulphide material and the leachability of both the sulphide and oxide material.
The Weaju sulphide ore gave a Bond BWi of 16.7 kwh/t and no problems are foreseen with achieving a primary grind of p80 75microns, as well as a regrind of P80 45microns, should this be required.
Both the Weaju oxide and sulphide composites, as supplied and tested, are deemed to be amenable to gravity recovery and cyanidation. The head grade of the oxide composite was 3.3 g/t of gold and the sulphide composites ranged between 5.5 and 6.1 g/t of gold. Gravity recoveries ranging from 39% to 48% were obtained for the oxide composite. For the sulphide composite, gravity recoveries between 40 to 48% were obtained.
For the oxide composite, residue grades ranging between 0.05g/t to 0.21g/t of gold giving recoveries between 92% and 98%, depending on the head grade, were obtained across all gravity / cyanidation tests conducted. For the sulphide composite, residue grades ranging between 0.55g/t to 0.31g/t of gold giving recoveries between 89% and 93%, depending on the head grade, were obtained across all gravity / cyanidation tests conducted. An acidic pre-oxidation stage, in addition to a lime pre-oxidation stage, was required to obtain a 0.31g/t of gold residue on the sulphide composite to achieve a 93% recovery.
Further gravity / leach testwork will be undertaken to comprehensively confirm the metallurgical response across the Weaju deposit and to assist with plant design and evaluation of recovery and reagent consumption. Additional work covering modelling of the gravity circuit, settling tests, cyanide destruction and arsenic precipitation tests together with kinetic column leaching will also be undertaken in the future.
About Aureus Mining Inc.
The Company's assets include the New Liberty gold deposit in Liberia (the "New Liberty Gold Project" or the "Project"), which has an estimated proven and probable reserve of 924,000 ounces of gold grading 3.4 g/t and an estimated measured and indicated mineral resource of 1,143,000 ounces of gold grading 3.63 g/t and an estimated inferred mineral resource of 593,000 ounces of gold grading 3.2 g/t. A Definitive Feasibility Study has been completed on the Project and construction has commenced with initial earthworks. The Project is expected to have an 8 year mine life and annual production of 119,000 ounces for the first 6 years of production. The Company has financed the Project's equity funding requirement, has mandated two banks for a project debt facility that have received credit committee approval, and has mandated one bank for a subordinated debt facility.
The New Liberty Gold Project is located within the Southern Block of the 100% owned Bea Mountain mining licence. This licence covers 457 km2 and has a 25 year, renewable, mineral development agreement. The North Block of the Bea Mountain mining license also hosts additional gold projects of Ndablama, Gondoja and Weaju, which are the focus of exploration programs during 2013. Ndablama has an inferred mineral resource of 451,000 ounces of gold grading 2.1 g/t and Weaju has an inferred mineral resource of 178,000 ounces of gold grading 2.1 g/t. The Archaen Gold exploration licence, which covers 89 km2, is also a focus of exploration for 2013, with Leopard Rock being the main target. The Yambesei (759 km2), Archaen West (112.6 km2), Mabong (36.6 km2) and Mafa West (15.6 km2) licences will also be subject to preliminary reconnaissance geological work.
The Company also has gold exploration permits in Cameroon.
Information in this report that relates to Metallurgical Test Work Results is based on information compiled by Glenn Bezuidenhout of DRA Mineral Projects (Pty) Ltd. Glenn Bezuidenhout is a Fellow of SAIMM, and has sufficient experience, which is relevant to the style of mineralization and type of deposit under consideration, and to the activity which he is undertaking to qualify as a Competent Person as defined by the NI-43-101 (National Instrument Code for the TSX). Glenn Bezuidenhout consents to the inclusion in this report of the statements based on his information in the form and context in which it appears.
This press release contains certain forward-looking information. All information, other than information regarding historical fact, that addresses activities, events or developments that Aureus Mining believes, expects or anticipates will or may occur in the future is forward-looking information. Forward-looking information contained in this press release includes, but may not be limited to, the future plans and objectives of Aureus Mining and their anticipated future growth, mineral resource estimates and the anticipated exploration and development activities of Aureus Mining. The foregoing and any other forward-looking information contained in this press release reflects the current expectations, assumptions or beliefs of Aureus Mining based on information currently available to Aureus Mining. With respect to the forward-looking information contained in this press release, Aureus Mining has made assumptions regarding, among other things: general business, economic and mining industry conditions; and it has also been assumed that no material adverse change in the price of precious and/or base metals occurs, no unusual geological or technical problems occur and no significant events occur outside of the normal course of Aureus Mining's respective business.
Such forward-looking information is subject to a number of risks and uncertainties that may cause actual results or events to differ materially from current expectations, including: risks normally incidental to exploration and development of mineral properties; uncertainties in the interpretation of results from drilling and test work; the possibility that future exploration, development or mining results will not be consistent with expectations; uncertainty of mineral resources estimates; adverse changes in precious and/or base metal prices; and future unforeseen liabilities and other factors including, but not limited to, those listed under "Risk Factors" in the Annual Information Form of Aureus Mining Inc. dated March 20, 2013 a copy of which is available on SEDAR at www.sedar.com, and in the Aureus Mining Admission Document, a copy of which is available at www.aureus-mining.com.
Any mineral resource figures referred to in this press release are estimates and no assurances can be given that the indicated levels of minerals will be produced. Such estimates are expressions of judgment based on knowledge, mining experience, analysis of drilling results and industry practices. Valid estimates made at a given time may significantly change when new information becomes available. While Aureus Mining believes that the mineral resource estimates in respect of their respective properties are well established, by their nature mineral resource estimates are imprecise and depend, to a certain extent, upon statistical inferences which may ultimately prove unreliable. If such mineral resource estimates are inaccurate or are reduced in the future, this could have a material adverse impact on Aureus Mining, as applicable. Due to the uncertainty that may be attached to inferred mineral resources, it cannot be assumed that all or any part of an inferred mineral resource will be upgraded to an indicated or measured mineral resource as a result of continued exploration.
Forward-looking information speaks only as of the date on which it is made and, except as may be required by applicable law, Aureus Mining disclaims any obligation to update or modify such forward-looking information, either as a result of new information, future events or for any other reason.
SOURCE Aureus Mining Inc.For further information:
Aureus Mining Inc.
David Reading / Paul Thomson
Tel: +44(0) 20 010 7690
Bobby Morse / Gordon Poole
Tel: +44(0) 20 7466 5000
RBC Capital Markets (Nominated Adviser and Joint Broker)
Jonathan Hardy / Richard Hughes
Tel: +44(0) 20 7653 4000
GMP Securities Europe LLP (Joint Broker)
Richard Greenfield / Alexandra Carse
Tel: +44(0) 20 7647 2800