Maiden Metallurgical Results for the Arizaro Project Indicate
Mineralization is Potentially Amendable to Heap Leach Processing
Vancouver, British Columbia � Goldrock Mines Corp. (TSX.V � GRM) May 1, 2013NR 13-06Goldrock Mines Corp. (�Goldrock� or the "Company") is pleased to announce that it has received initial metallurgical test work results for the Arizaro project. Arizaro is a gold-copper porphyry discovery located 3 km southeast of Goldrock�s 100% owned and fully permitted developmental stage Lindero gold deposit.
With the view to potentially utilizing the Lindero heap leach processing facility, preliminary metallurgical testing was conducted to start profiling leaching behavior of the typical Arizaro medium to high grade mineralization. This metallurgical test work was undertaken by Kappes, Cassiday and Associates in Reno, Nevada.
Four cyanide bottle roll test results were conducted on both fresh and oxide mineralization and show very favorable coarse fraction gold recoveries of between 64% and 73%. These recoveries are in a range typical of the early bottle roll test work for the Lindero deposit, and provide a preliminary indication that the Arizaro mineralization is amenable to heap leach gold extraction.
Diamond drill core samples were crushed to 80% passing 9.5 mm mesh, which is the nominal ore crush size for the designed crushing circuit at Lindero. The composites were prepared to produce representative samples of medium and high gold grades for oxide (weathered) and fresh (non-weathered material) portions of the Arizaro mineralization. Cyanide bottle roll metallurgical tests were then run on the sample composites at 1000 ppm cyanide concentrations for more than 50 days at a pH of 10.5.
The following table shows the results from the Cyanide bottle roll metallurgical test work:
Gold Grade |
Ore Type |
Calculated Head (g Au/T) |
Calculated Head (g Cu/T) |
Gold Recovery |
Copper Recovery |
Leach Time (days) |
Final pH |
% Oxide |
% Fresh |
Medium Grade |
52 |
48 |
0.42 |
1,974 |
73% |
17% |
53 |
10.5 |
Medium Grade |
52 |
48 |
0.62 |
2,230 |
64% |
26% |
53 |
10.4 |
High Grade |
0 |
100 |
1.04 |
3,326 |
72% |
33% |
53 |
10.7 |
High Grade |
60 |
40 |
1.86 |
3,367 |
67% |
22% |
53 |
10.5 |
Gold analyses of each particle size fraction from the bottle roll tails indicates that there is good leaching in the coarser fractions. The relationship between crush size and recovery will be tested in further more detailed test work programs. Cyanide and lime consumptions for the bottle rolls were comparable to those from Lindero, which are well within the average range of reagent consumptions for a heap leaching project.
Paul Matysek, President and CEO, commented
�This maiden metallurgical test work certainly increases our confidence that Arizaro has the potential to add to the Lindero project reserve base. The recently released Lindero feasibility study projects average gold production of 128,000 oz/year over the first three years of operation, and 109,000 oz/year over the initial nine years of operation. Adding Arizaro material to this production schedule could potentially add to mine life and gold production, enhancing an already robust project.�The Company is now working towards the release of a maiden NI 43-101 technical report for the Arizaro project in the second quarter of 2013, as well as a commencing detailed metallurgical test work, including heap leach column test work and detailed mineralogical analyses of the Arizaro mineralization.
Arizaro BackgroundThe Arizaro porphyry body was identified prior to the discovery of the Lindero gold deposit in 1999. The Arizaro porphyry system, as defined by drilling, surface sampling and mapped alteration covers a 600 metre by 500 metre surface area. Gold-copper mineralization occurs from surface to a true vertical depth of 300 metres and remains open for expansion in all directions. The Company initially tested the discovery with 16 diamond drill holes, all of which had significant mineralized intercepts with numerous thick sections greater than 100 meters with grades greater than 0.30 g/t gold and 0.15% copper, and with one hole returning 48 meters of 1.38 g/t gold and 0.36% copper.
Qualified PersonDavid Keough FAusIMM(CP) of Goldrock Mines Corp is a "qualified person" as such term is defined in National Instrument 43-101 (Standards of Disclosure for Mineral Projects) and has reviewed and approved the technical information and data included in this press release.
ON BEHALF OF THE BOARD OF DIRECTORS,
�Paul Matysek� Paul Matysek, M.Sc., P.Geo
President and CEO
For additional information
About Goldrock Mines Corp. Goldrock Mines Corp. is an emerging gold producer focused on the development of its 100% owned Lindero gold deposit located in Salta province, northwestern Argentina. The Company has been granted the primary mining permit by the Salta provincial government allowing the Company to develop the Lindero open pit, heap leach gold mine. Results of the Lindero Feasibility Study have recently been announced. Production will be at an initial throughput rate of 15,000 TPD, increasing to 18,750 TPD during the first year of operation. Average annual production will be 109,000 ounces during the first nine years. The Company has assembled an experienced operating team and is now arranging project financing with commercial production anticipated in 2015. Goldrock�s objective is to become a mid-tier gold producer with annual gold production of 250,000 ounces per year through organic growth and accretive acquisitions of near-term producing assets.
Neither the TSX Venture Exchange, nor its Regulation Services Provider accepts responsibility for the adequacy or accuracy of this release. Caution Regarding Forward-Looking Statements This press release includes certain statements that may be deemed �forward-looking statements�. All statements in this discussion, other than statements of historical facts, that address future exploration drilling, exploration activities, anticipated metal production, internal rate of return, estimated ore grades, commencement of production estimates and projected exploration and capital expenditures (including costs and other estimates upon which such projections are based) and events or developments that the Company expects, are forward looking statements. Although the Company believes the expectations expressed in such forward looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or developments may differ materially from those in forward-looking statements. Factors that could cause actual results to differ materially from those in forward-looking statements include metal prices, exploration success, continued availability of capital and financing, and general economic, market or business conditions. Accordingly, readers should not place undue reliance on forward-looking statements.