Capstone Mining Corp. (CS: TSX) today announced assay results for twenty-six new holes from the Wildfire / Copper Keel horizons at the Minto Mine.
Exploration drilling at the Minto Mine is now finished for the season and geologic modelling has started with the objective of completing the first NI43-101 compliant mineral resource estimate for Wildfire and Copper Keel before the end of 2010. The extent of both the shallower (Wildfire) and deeper (Copper Keel) mineralized horizons have increased significantly as a result of this recent drilling and the Copper Keel horizon, in particular, is still open to the north and east.
"The Wildfire discovery and the significantly expanded Copper Keel mineralization continue to return good thicknesses and grades," said Stephen Quin, President of Capstone. "These zones remain open to further expansion and offer potential for significant mineral resource additions based both on the drilling completed in 2010 and the potential for further expansions in 2011, when exploration drilling resumes in early 2011." The remaining drill results from the 2010 Minto exploration program will be released before the end of 2010.
Wildfire/Copper Keel Discoveries
The original Copper Keel mineralization was a blind discovery made in 2006 at a depth of 175 metres as a result of geologic interpretation. However, the discovery was not followed up until much later as exploration was then focused on evaluating the potential of the shallower Area 2, Ridgetop and Minto North targets, all of which are now deposits determined to be amenable to open pit mining. The Wildfire discovery was made in 2010 as a result of testing a geophysical target. However, when the first Wildfire hole continued to depth beneath the discovery, it intercepted a second zone of mineralization, which we now believe to be a significant extension of the original Copper Keel discovery. Subsequent drilling, including these results released today, have confirmed the presence of an upper NNE-trending "Wildfire" horizon (potentially amenable to open pit mining), and a deeper NNW-trending Copper Keel zone linking up to the original 2006 discovery (potentially amenable to underground mining).
Geologic modelling for the Wildfire discovery and the significantly expanded Copper Keel horizon is underway, with the objective of completing a maiden mineral resource estimate for these areas before the end of 2010. However, assays for approximately 43 holes in these areas remain outstanding and the timing for completion of mineral resource estimates is dependent on the timely receipt of assay results. As a result of this timing, the fact that the limits of mineralization are not defined and the probability that some portions of these mineral resources will be in the inferred category (pending infill drilling in 2011), the Wildfire and Copper Keel zones will be excluded from the Phase V Pre-feasibility Study ("Phase V PFS") currently in progress. Capstone will make a subsequent update to the Phase V PFS, once the limits of the mineralization have been defined and there is sufficient drill hole density to increase the mineral resource classification to an indicated category or better. Capstone plans to start drilling again in early 2011.
Quality Assurance
The technical information in this news release has been prepared in accordance with Canadian regulatory requirements set out in National Instrument 43-101 and reviewed by Stephen P. Quin, P. Geo., President of Capstone Mining Corp. The exploration activities at the Minto Mine are carried out under the supervision of Brad Mercer, P. Geol., VP, Exploration of Capstone.
The analytical method for the copper and silver analyses is aqua regia digestion of the samples followed by atomic absorption spectroscopy. Gold is analysed by fire assay fusion with atomic absorption spectroscopy finish for gold. Analyses are carried out by ALS CHEMEX in North Vancouver. When visible gold is noted in drill core samples or regular fire assay values appear abnormally high, the pulp and screen metallic assay method is used to determine the total gold content and gold contents of different size fractions. This is considered industry best practice when dealing with coarse gold mineralization where a nugget effect is suspected. This determination is accepted as the most representative value and is used in the assay database for mineral resource calculations. Blank and standard samples are used for quality assurance and quality control. Where more than two check samples assay outside expected ranges, the entire batch is re-assayed. After the completion of planned drill programs at Minto, random check assays will be carried out by Inspectorate-IPL of Vancouver.
Source: Capstone Mining Corp.