https://at.marketwire.com/accesstracking/AccessTrackingLogServlet?docid=0787736001&sourceType=1https://media3.marketwire.com/logos/20120224-merc_reg.jpg VANCOUVER, BRITISH COLUMBIA -- (Marketwire) -- 05/04/12 -- Mercator Minerals Ltd (TSX:ML) ("Mercator" or the "Company") announces that it has revised production guidance for its wholly-owned Mineral Park mine in Arizona, which is now expected to produce approximately 89 million copper equivalent pounds(1) during 2012. This compares to the prior guidance issued by the Company in January 2012, which estimated production of 90 to 100 million copper equivalent pounds(1).
Hard Ore & Mill Throughput
The Company believes the previously disclosed impact of hard ore on mill throughput has now been resolved. During the first quarter of 2012, harder than expected ore reduced mill throughput rates, which resulted in lower than expected copper production. The updated guidance is based on the concentrator achieving design throughput levels of 50,000 tons per day ("tpd"), with a hard ore blend of up to 40% of total mill feed. This threshold has been determined based on periods of operation with different ratios of hard ore in the mill feed.
Transition Zone Mineralization
The 2012 mine plan at the Mineral Park mine includes mining through the transition from supergene enriched copper material into primary hypogene copper mineralization. Mining of the transition zone has encountered a lower percentage of higher grade supergene copper mineralization than expected from the mineral resource model, resulting in a lower copper grade from this material than anticipated, while molybdenum grades are unaffected.
Approximately 20 percent of the material expected to be processed under the 2012 mine plan is comprised of transition zone ores. The Company believes that, as mining passes through the transition zone, copper grade and tonnage reconciliation should better correlate with the block model since the copper grades in hypogene mineralization both within and below the transition zone is less subject to the variability associated with secondary enrichment. Overall, the transition zone represents a small percentage of the overall mineral resource and the life-of-mine mineral reserves for the Mineral Park Mine.
The Company is presently evaluating the impact on the five year mine plan of mining other areas of the deposit that have a component of similar transitional material.
Updated 2012 Guidance
As a result of the lower head grade currently being mined in the transition zone, the impact of harder ore and the high oxide material processed through the mill in the first quarter 2012, the Company has revised its 2012 production guidance accordingly. As discussed above, the revised guidance is also based on the 50,000 tpd average throughput for the balance of the year:
Revised 2012 Production Guidance
Q1-2012 Q2 to Q4-2012 Total Actual Forecast 2012-------------------------------------------------------------------------Copper in concentrate (million lbs) 9.0 30.0 39.0Copper cathode (million lbs) 0.9 2.7 3.6 -------- ------------------------Total Copper 9.9 32.7 42.6Molybdenum in concentrate (million lbs) 2.3 8.1 10.4Silver (000 ounces) 211 335 546Copper equivalent (1) (million lbs) 20.1 69.5 89.6Milled tons (millions) 4.4 13.7 18.1Average copper grade 0.140% 0.137% 0.138%Average molybdenum grade 0.036% 0.039% 0.039%Average copper recoveries 72.6%(2) 80.0% 78.3%Average molybdenum recoveries 70.9%(2) 75.0% 74.1% (1) All references to copper equivalent production is calculated using a molybdenum/copper ratio of 4.53, based on the Company's estimated 2012 metals prices. (2) Recoveries are lower in Q1/12 as a result of processing partially oxidized ore stockpiles, which stockpiles have been fully depleted.
As noted in a news release dated April 10, 2012, blending of partially oxidized stockpiled ore through the mill during the first quarter 2012 reduced metal recoveries. Mining of the partially oxidized stockpile has since been completed and recoveries have returned to normal.