VANCOUVER, British Columbia, February 2, 2012 /PRNewswire/ --
- Additional 67 Million Pounds of Copper in M&I Mineral Resource and New High Grade Copper-Gold Discovery
Capstone Mining Corp. ("Capstone") (TSX: CS) today announced the result of an updated National Instrument 43-101 compliant mineral resource estimate for the Wildfire/Copper Keel area at its Minto Mine in Yukon, Canada. Follow-up drilling in the Copper Keel region of Minto South Deposit ("MSD") in the second half of 2011 has added an additional 67 million pounds of copper resource in the measured and indicated categories. At a 0.5% copper cut-off grade, total mineral resources at the Minto Mine exceeds 1.1 billion pounds of copper.
In addition, the 2011 drill program produced a new discovery called Fireweed. A total of 26 holes were drilled on Fireweed "A" and "B". The best intercept to date is 3.2% Cu & 1.0g/t Au over 16.6 metres including 6.8% Cu and 1.9g/t Au over 7.1 metres in hole 11SWC-871 at Fireweed A and 3.4% Cu and 1.4g/t Au over 14.4 metres including 4.2% Cu & 1.3g/t Au over 7.6 metres in hole 11SWC-882 at Fireweed B. Fireweed "A" is located approximately 200 metres east of the Minto East deposit and Fireweed "B" lies a further 170 metres east of Fireweed "A". Fireweed drilling highlights are summarized in a table below and the full results are attached.
"Exploration success at Minto continues to translate into mineral resource additions to support our objective of organic growth at our existing mining operations," said Brad Mercer, Vice President, Exploration for Capstone. "Since 2006, the Minto Mine has achieved steady mineral resource increases through a program of discovery followed by feasibility studies in a series of phases. This updated mineral resource will be included in the next Pre-Feasibility Study, which is currently underway."
"The latest new Fireweed discovery, not yet included in any mineral resource estimate, was made by testing a geological target that became compelling after we completed a new 3D geology model of MSD," continued Mr. Mercer. "Future exploration at Minto will focus on depth, exploring beyond the limits of our existing geophysical surveys as our understanding of Minto's geology evolves," he added.
Drilling operations have begun again in 2012 on a $4.8 million exploration drill program (23,500 metres). Drilling will initially in-fill the relatively shallow gap between the MSD and the Ridgetop deposits. After that, the Company will follow-up its latest exploration success by refocusing on Fireweed and on the potential for further high grade mineralization at depth in the Minto system. As in previous years, the 2012 program will be conducted in two phases, winter and summer, separated by a pause in the spring for thaw and freshet. It is anticipated that the Company will provide an update of exploration results part way through 2012 when drilling is paused between phases.
Minto South Deposit (MSD) - Updated Mineral Resource Estimate effective as at December 31, 2011
The Wildfire/Copper Keel area is a southeastwardly extension of the Minto South Deposit. On May 30, 2011 the Company announced a mineral resource gain of 219 million pounds of copper from drilling conducted in 2010 and early 2011 in the Wildfire/Copper Keel area of MSD. Geological modelling incorporating these drill holes indicated geological continuity between the Wildfire/Copper Keel region and the Area 2/118 region and supported a geological reinterpretation indicating these areas are part of one larger deposit (MSD) and not separate deposits as initially thought. Subsequently, drilling in mid to late 2011 in the same area now brings the total holes in the current estimate to 423 and added a further 67 million pounds of copper in the M&I Class for MSD. Data from these latest drill holes add further confidence in geological continuity of mineralization modelled in the previous MSD estimate and also expands the limits of mineralization northward on the Copper Keel levels of MSD from the May 30, 2011 model.
Below are tables summarizing the new total mineral resource estimate for MSD and the gain in mineral resources at MSD since the last estimate.
Total Mineral Resources by Class for the Minto South Deposit**, *** at a 0.5% copper cut-off grade ("Cu COG")
Contained Contained Contained
Cu Gold Silver
Tonnes Copper Gold Silver (000's (000's (000's
Classification (000's)* (%) (g/t) (g/t) lbs)* oz)* oz)*
Measured (M) 10,387 1.21 0.45 4.07 278,028 151 1,360
Indicated (I) 28,556 0.98 0.32 3.44 616,152 290 3,162
Total (M+I) 38,943 1.04 0.35 3.61 894,180 441 4,522
Additional Inferred 8,134 0.81 0.24 2.93 145,718 63 767
*Rounded to nearest thousand; totals may not sum exactly due to rounding.
** Includes material mined but not processed during pre-stripping activities in the Area 2 region of MSD and currently held in stockpile.
Mineral Resources Addition by Class in the Wildfire/Copper Keel Region of MSD since May 30, 2011 at a 0.5% Cu COG
Contained Contained
Gold Silver
Tonnes Copper Gold Silver Contained Cu (000's (000's
Classification (000's)* (%) (g/t) (g/t) (000's lbs)* oz)* oz)*
Measured (M) 296 0.54 0.15 4.17 3,554 1 40
Indicated (I) 2,262 1.27 0.37 4.80 63,446 27 349
Total (M+I) 2,558 1.19 0.35 4.73 67,000 28 389
Additional Inferred 705 0.74 0.33 4.41 11,422 8 100
*Rounded to nearest thousand; totals may not sum exactly due to rounding.
Mineral resources that are not mineral reserves do not have demonstrated economic viability. Mineral resource estimates do not account for mineability, selectivity, mining loss and dilution. These mineral resource estimates include inferred mineral resources that are normally considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves. There is also no certainty that these inferred mineral resources will be converted to measured and indicated categories through further drilling, or into mineral reserves, once economic considerations are applied.
Total Mineral Resources at the Minto Mine as of December 31, 2011
The table immediately below summarizes the total mineral resource on the Minto property at a COG of 0.5% Cu. It includes the undeveloped Minto North, Minto East and Ridgetop deposits and the Minto South deposit where development (pre-stripping) is underway plus a small amount of resource remaining on the east flank of the Minto Main open pit that is relatively low grade and not considered in any current mine plan.
Total Mineral Resources by Class for all Minto Mine Deposits**, *** at a 0.5% Cu COG
Contained Contained Contained
Cu Gold Silver
Tonnes Copper Gold Silver (000's (000's (000's
Classification (000's)* (%) (g/t) (g/t) lbs)* oz)* oz)*
Measured (M) 14,828 1.35 0.53 4.43 441,744 254 2,114
Indicated (I) 33,103 0.98 0.32 3.42 714,010 341 3,643
Total (M+I) 47,931 1.09 0.39 3.73 1,155,754 595 5,758
Additional
Inferred 8,493 0.81 0.24 2.88 151,764 65 788
*Rounded to nearest thousand; totals may not sum exactly due to rounding.
** Includes material mined but not processed during pre-stripping activities in the Area 2 region of MSD and currently held in stockpile.
***Includes any resources remaining in the Minto Main Deposit not considered in current mine plans but excludes material existing in stockpiles that originated from the Minto Main Deposit.
Appended to this release are tables summarizing both the MSD and the total Minto Mine mineral resources at various copper COGs. Please note that estimated grade and tonnage stated at copper COGs below 0.5% copper are for illustrative purposes to show the sensitivity of the mineral resource to decreasing copper COGs.
Also note that mineral resources at higher cut-off grades are also for illustrative purposes and do not necessarily imply a higher potential for economic extraction. Only those mineral reserves determined by previous feasibility studies to be mineral reserves are currently considered economically viable. The property-wide mineral resource numbers reported herein are inclusive of all previously defined mineral reserves that are currently supported by previous pre-feasibility work. Please refer to the Technical Report titled Minto Phase V Preliminary Feasibility Study Technical Report dated December 15, 2010 filed on SEDAR for any further discussion about mineral reserves at Minto. A new pre-feasibility study (Phase VI) is currently underway to apply economic considerations to the newly estimated mineral resources in the Wildfire/Copper Keel extension of the MSD.
Mineral Resource Estimate Methodology
The mineral resource estimate for the Wildfire/Copper Keel addition to the Minto South Deposit reported herein was prepared by SRK Consulting of Vancouver. The estimate was completed in Gemcom Software GEMS© using a three dimensional block model (10 metres by 10 metres by 3 metres (vertical) block size). The mineralization was interpreted into nine distinct domains, modelled as wireframes and used as hard boundaries to constrain estimation. Geostatistical analysis was completed on the 1.5 metre composite assay data for each of the metals, and variograms were defined for each domain of mineralization. The grades for copper and gold were interpolated into the block model using ordinary krigingmethod, whereas the silver grades were interpolated using the inverse distance squared method only.