Minefinders Selects Dolores Gold and Silver Recovery Process.Business Editors VANCOUVER, British Columbia--(BUSINESS WIRE)--April 29, 2004 Minefinders Corporation Ltd. (the "Company") (AMEX AMEX See: American Stock Exchange :MFN MFN abbr. most-favored nation ) (TSX TSX Toronto Stock Exchange (TSE before April, 2002) TSX Transfer from Stack Pointer to Index TSX True Space Extension :MFL MFL Minimum Flows and Levels (ground water) MFL Modern Foreign Language MFL Magnetic Flux Leakage MFL Medium Flood (stage lighting) MFL Manitoba Federation of Labour ) has selected a combined flotation and heap leach mineral recovery process for the final feasibility study The analysis of a problem to determine if it can be solved effectively. The operational (will it work?), economical (costs and benefits) and technical (can it be built?) aspects are part of the study. Results of the study determine whether the solution should be implemented. on its Dolores Dolores (or Delores) was a common given name (until the 1960s in the USA); it is cognate with the English word "dolorous" (meaning sorrowful) and equivalent in meaning. gold-silver deposit located in Chihuahua, Mexico. The selection was made after extensive evaluation of standard heap leach, flotation, agitated ag·i·tate v. ag·i·tat·ed, ag·i·tat·ing, ag·i·tates v.tr. 1. To cause to move with violence or sudden force. 2. cyanide leaching, and pulp agglomeration ag·glom·er·a·tion n. 1. The act or process of gathering into a mass. 2. A confused or jumbled mass: , individually, and in combination with each other. In the selected process, high-grade and sulfide ores containing the majority of the project gold and silver will be preferentially directed to the mill and flotation plant, while low-grade ores will report directly to the leach pad for standard, low-cost heap leach processing. The addition of flotation to the Dolores mine plan is expected to substantially increase the overall percentage recovery of contained silver, while maintaining the percentage recovery of contained gold at favorable levels approximating those previously announced. The evaluation of the different process scenarios was completed on the basis of estimated capital and operating costs operating costs npl → gastos mpl operacionales and on recovery information generated from laboratory metallurgical testing. Following this analysis, it was determined that a combined flotation with heap leach recovery operation would provide the flexibility required to maximize returns at current and higher precious metals Precious Metals Valuable metals such as gold, iridium, palladium, platinum, and silver. Notes: Investing in precious metals can be done either by purchasing the physical asset, or by purchasing futures contracts for the particular metal. prices and remain cost effective in a lower price environment. The final bankable bank·a·ble adj. 1. Acceptable to or at a bank: bankable funds. 2. Guaranteed to bring profit: a bankable movie star. feasibility for the project will be based upon optimization of this operating scenario. Mark Bailey
Mark Bailey (born 26 November, 1970) is a cricket player in Hamilton, New Zealand. He played one one-day international for the New Zealand cricket team. , Minefinders' President and CEO (1) (Chief Executive Officer) The highest individual in command of an organization. Typically the president of the company, the CEO reports to the Chairman of the Board. commented: "The final selection of the Dolores operating process marks a major milestone in the commercialization of the project. While the metallurgy at Dolores has always been very good, we have taken the time necessary to ensure that all of the possible recovery processes have been thoroughly evaluated, so as to maximize the project's potential." Projected Flotation Recoveries Flotation test results from composited ore-grade intervals (shown in the first table below) from the Dolores deposit demonstrated a highly efficient recovery process, yielding enhanced gold recovery and very significantly increased silver recovery. These recovery efficiencies are expected to have a particularly positive financial impact, due to the increase in sulfide resources within the project area, the discovery of potentially important base metal concentrations, and recent increases in silver prices. The table indicates the projected total recoveries for each ore-type, based on results from SGS SGS Société Générale de Surveillance SGS Symantec Gateway Security (appliance) SGS School of Graduate Studies SGS Subgrid Scale SGS Singapore Government Securities SGS Shell Global Solutions Lakefield lock-cycle and other testing, using the proposed process, i.e. recovered gold and silver in the flotation concentrate is then cyanide leached and combined with gold and silver recovered from the leached tails to provide the "Total Recovery" percentages:
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Total Total
Composite Type Flotation Flotation Recovery Recovery
Au Ag Au Ag
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Mixed Oxide/sulfide ore 65% 67% 93% 82%
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Sulfide ore 91% 90% 90% 94%
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Sulfide/base-metal ore 92% 90% (i) (i)
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(i) total recovery results for sulfide/base-metal ores are pending
Metallurgical samples were composited to represent dominant ore-types found throughout the Dolores deposit and sent to SGS Lakefield Research Limited of Ontario, Canada for testing. The three ore-types selected include: 1) Composite 1 - mixed oxide and oxide/sulfide ores, 2) Composite 2 - simple sulfide ores, and 3) Composite 3 - sulfide ore with a significant base-metal (Pb-Zn) component. Each composite was subjected to a wide series of flotation tests using a range of variables in an effort to optimize flotation recoveries and processing. The table indicates that leaching of mixed and oxide tails, although requiring an additional circuit, provides a significant contribution to total recovery; and that leaching of sulfide tails may not be necessary. A cost/benefit analysis of this issue is ongoing. An additional 15 samples, totaling 105 kilograms, are undergoing variability testing to further characterize flotation response to the different rock types and oxidation states of ore-grade material from the Dolores deposit. Flotation testing is ongoing for the sulfide-base metal composite which has produced marketable lead and zinc concentrates which could be sent to a smelter to further enhance project economics. Projected Heap Leach Recoveries Heap leach recoveries from lower grade ores are estimated from recovery data indicated by the 32 columns of composited Dolores material tested and/or compiled by McClelland Labs of Sparks, Nevada. While additional data from ongoing column leach tests are being accumulated, the test results to date are sufficient to provide the projected recoveries presented below: ----------------------------------------------- Composite Type Recovery Au(i) Recovery Ag(i) ----------------------------------------------- Oxide ore 78% 45% ----------------------------------------------- Mixed ore 70% 50% ----------------------------------------------- Sulfide ore 59% 59% ----------------------------------------------- (i) presumed 100% passing -3/8 inch crush Summary It is expected that the proposed combination of flotation and heap leach circuits will ensure optimal project returns and substantially increase Minefinders' leverage to current and higher gold and silver prices at moderate projected capital and operating costs. Details of the Dolores project economics will be released in conjunction with the completion of the feasibility study. About Minefinders Minefinders is a highly successful precious metals exploration company with its advanced Dolores gold and silver deposit and several ongoing exploration projects in Sonora, Mexico. The Company is presently working on completing a feasibility study "A Feasibility Study" is an episode of the original The Outer Limits television show. It first aired on 13 April, 1964, during the first season. It was remade in 1997 as part of the revived The Outer Limits series with a minor title change. on the Dolores deposit and conducting exploration drill programs on its other prospects. Mark H. Bailey, MSc., P.Geo., a Qualified Person as defined by National Instrument 43-101, supervised the preparation of the technical information in this release. On Behalf of the Board of Directors MINEFINDERS CORPORATION LTD. Mark H. Bailey, President and Chief Executive Officer Safe Harbor Safe Harbor 1. A legal provision to reduce or eliminate liability as long as good faith is demonstrated. 2. A form of shark repellent implemented by a target company acquiring a business that is so poorly regulated that the target itself is less attractive. Statement under the United States Private Securities Litigation An action brought in court to enforce a particular right. The act or process of bringing a lawsuit in and of itself; a judicial contest; any dispute. When a person begins a civil lawsuit, the person enters into a process called litigation. Act of 1995: Statements in this release that are forward-looking, including statements relating to the size, and growth in size, of the Company's mineral resources and the timing of the further exploration and development of the Dolores project, are subject to various risks and uncertainties concerning the specific factors identified above and in the Company's periodic filings with the Ontario Securities Commission The Ontario Securities Commission (OSC) is a regulatory agency which administers and enforces securities legislation in the Canadian province of Ontario. The OSC is an Ontario Crown corporation which reports to the Ontario legislature through the Minister of Finance. and the U. S. Securities Exchange Commission. Such information contained herein represents management's best judgment as of the date hereof based on information currently available. The Company does not intend to update this information and disclaims any legal liability to the contrary. |
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