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VANCOUVER, British Columbia, Feb. 24 /PRNewswire/ -- Miramar Mining Corporation (OTC Bulletin Board: MAENF - news; Toronto: MAE - news) announces today that it has identified several refractory gold opportunities at its Yellowknife operations that could allow it to further increase gold production and reduce costs through the full utilization of its refractory processing capabilities. Earlier this week Miramar announced that the acquisition of the Giant Mine has allowed Miramar to boost forecast production from its Yellowknife operations to an annualized rate of 130,000 oz/year for the next two years(+). Cash costs are forecast to average under US$260/oz(+).
``Our strategy in Yellowknife is to continue to seek out ways to increase gold production, reduce operating costs and extend the operating life(+). These developments represent a tremendous opportunity for Miramar to achieve its objectives,' said Tony Walsh, Miramar's President & CEO. ``Miramar is moving rapidly to evaluate the potential for near term production increases from these opportunities.'
Refractory Gold Opportunities
``With the successful operation of the autoclave, Miramar has been evaluating opportunities to more fully utilize our ability to process refractory gold,' said Mr. Walsh. ``The availability of additional refractory gold has created an opportunity to boost refractory gold production from the Con and Giant mines, while reducing operating costs below the currently forecast levels(+).' Potential sources of refractory feed include refractory resources at the Con and Giant mines and a newly identified significant gold resource in tailings at the Giant Mine that could be upgraded prior to processing in Miramar's autoclave. Refractory gold is gold tied up in ores that require additional processing, such as autoclaving, to liberate the gold prior to the conventional leaching process used to recover gold in free milling ores.
Gold Tailings Reprocessing
Through its on-going assessment of the Giant Mine, Miramar has examined the potential to retreat higher-grade iron rich tailings, where a significant resource has been identified. This resource is contained in four separate tailings ponds and, based on detailed drilling completed in the late 1980's, is estimated at 11.6 million tons grading 0.055 oz/ton gold, for a contained 640,000 oz of gold. Grades in individual tailings ponds vary from a low of 0.033 oz/ton gold in the newest ponds to a high of 0.097 oz/t gold in the oldest. Miramar intends to focus on reprocessing the highest-grade tailings first.(+)
Previous attempts to reprocess this material through whole ore leaching failed due to the refractory nature of the gold. However, test work using magnetic separation indicated that approximately 50-55% of the gold could be recovered into a low weight, high gold grade iron oxide concentrate that could be processed in the Con autoclave(+). ``This would he very low cost material to process as the tailings are easily accessible, require no crushing or grinding and magnetic separation is inexpensive,' said Brian Labadie, Miramar's Senior Vice President Operations(+). ``Processing such a concentrate in the autoclave is straightforward and low cost, as the material is already largely oxidized.' Cash operating costs for the tailings reprocessing are estimated to be approximately US$200 per oz of gold recovered(+).
Additional Environmental Benefits from Iron Content
``Putting the tailings concentrate through our autoclave could have substantial benefits in addition to adding to our gold production,(+)' said Mr. Labadie. In the autoclave, arsenic in the presence of sufficient iron is stabilized as ferric arsenate an environmentally benign mineral that can safely be disposed of in tailings. Blending in a high iron content concentrate could allow us to accelerate the processing of Miramar's surface stored arsenical wastes, significantly reducing reclamation costs at the Con Mine,`` he said(+). The Con Mine has an estimate of 85,000 tons grading 0.47 oz/ton in arsenical wastes, which material is stored in surface containment ponds and is currently being processed through the autoclave as part of Miramar's concurrent reclamation under its 5-year mine plan. Further, this concentrate could provide an inexpensive source of iron for the stabilization of the 270,000 tons of arsenical wastes stored underground at the Giant Mine, if processed through the Con's autoclave(+).
Refractory Resource Opportunities
Miramar's current 5-year plan for the Con Mine was developed on a stand-alone basis, without considering any potential benefits from ownership of the Giant Mine. The 5-year plan focused on mining the lowest cost, most accessible ounces and left behind significant refractory resources which did not meet the plans' objectives. Refractory resources at the Con total 1.5 million tons grading 0.31 oz/ton gold, for a contained 467,000 oz. Recent success in processing refractory ore suggests that the refractory circuit at the Con mill can handle up to 50% more than the currently planned 600tpd-processing rate (Con and Giant ore combined) and, given the improved operating costs resulting from the acquisition of the Giant Mine, the economics of these resources are being reassessed(+).
Further, the Giant Mine has a significant gold resource of, outside of the Supercrest area that is currently being mined, totaling 5.7 million tons grading 0.23 oz/ton for a contained 1.31 million oz of gold. Preliminary evaluations suggest several higher-grade areas within this resource could potentially be mined and shipped to the Con for processing, as is currently being done at Supercrest.
``Successful operation of the Con autoclave, increased throughput in the refractory circuit and a supply of gold rich iron concentrates from the Giant tailings could make these resources profitable to mine and process at current gold prices, resulting in increased production, reduced operating costs and an extended mine life(+),' confirmed Mr. Walsh.
Implementation Plan
Miramar has several initiatives underway to take advantage of the opportunities discussed above. Miramar plans to complete a drilling and metallurgical testing program to support a feasibility study on the recovery of gold from the Giant tailings(+). The study should be completed by the summer of 2000 so that extraction and processing could begin as early as the spring of 2001, if the results of the study are favourable(+). ``Preliminary estimates suggest the capital cost for a magnetic separation plant are in the range of $2-3 million and operating costs would fall, (+)' said Mr. Labadie. ``Most of the plant and infrastructure is already in place to support such an operation.'
To fully optimize the refractory gold opportunities available, Miramar has retained consulting engineers Fluor Daniel Wright to examine alternatives that might allow further increases in the Con refractory processing capacity, such as the addition of a preoxidation circuit, an expansion of the existing autoclave vessel as well as other measures. This report is expected to be completed by September 2000 and will be used in the assessment of maximizing available reserves at the Yellowknife operations(+).
The existing resources at the Con and Giant mines are currently being assessed to determine which portions of the resources could be converted to reserves and what the impact would be on additional production and reduced costs.
(+)This News Release contains forward-looking statements within the meaning of the United States Private Securities Litigation Reform Act of 1995 concerning the Company's plans for the operation of the Con and Giant Mines. Reserve and resource estimates also may be deemed to be forward-looking statements because they reflect estimates of amounts of precious metals that will be found to be present in mineral deposits, and the assessment that the deposit can be mined profitably in the future. These forward-looking statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ materially from those reflected in this forward-looking statement, including, without limitation, risks and uncertainties relating to fluctuating precious and base metals prices; uncertainties in interpreting drilling and other test results; recovery rates; accidents, equipment breakdowns, labour disputes and severance costs or other unanticipated difficulties with or interruptions in production, the possibility of unexpected costs and expenses relating to environmental issues, uncertainties relating to the need for government approvals and the cooperation of government agencies in regards to the environmental liabilities of the Giant mine and other risks and uncertainties, including those described in the Company's Annual Report on Form 20-F for the year ended December 31, 1998 and Reports on Form 6-K filed with the Securities and Exchange commission.
All resource estimates reported in this disclosure are calculated in accordance with Toronto Stock Exchange National Instrument 43-101 and the Canadian Institute of Mining and Metallurgy Classification system. These standards differ significantly from the requirements of the United States Securities and Exchange Commission, and resource information reported in this disclosure may not be comparable to similar information reported by United States companies. The terms ``Resource(s)' and ``Reserve(s)' normally may not be included in documents filed with the Securities and Exchange Commission or are referred to as ``mineralization' or ``mineral deposits'.
Certain forward-looking statements in this report are indicated with a ``(+)'
For further information:
Tony Walsh, President & CEO, or
Brian Labadie, Senior Vice-President Operations
Miramar Mining Corporation
Tel: 604-985-2572; Fax: 604-980-0731
Toll Free 1-800-663-8780
info@miramarmining.com
SOURCE: Miramar Mining Corporation
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