CS Capstone Copper Corp

At a 0.5% Copper cut-off grade, total mineral resources at the Minto Mine now exceeds 1 billion pounds of copper

VANCOUVER, May 30, 2011 /PRNewswire/ - Capstone Mining Corp. ("Capstone") (TSX: CS) today announced the result of a National Instrument 43-101 compliant mineral resource estimate for the Wildfire/Copper Keel area at the Minto Mine in Yukon, Canada.  Wildfire/Copper Keel is now recognized as a southeastwardly extension of the Area 2/118 deposit which is currently being pre-stripped in preparation for mining. The combined Area 2/118/Copper Keel/Wildfire mineral resources are now recognized as a single mineral deposit and will be referred to as the Minto South Deposit ("MSD"). The Copper Keel region of this larger deposit model is still open and exploration drilling is currently in progress with two drills.

"The exploration success at Minto continues to be translated into mineral resource additions that support the near term growth strategy at our mining operations. Since 2006 the Minto Mine has realized steady expansion through a program of discovery and feasibility in a series of phases that have increased mine life and throughput. Capstone plans to follow up this latest mineral resource addition with a new Pre-Feasibility Study (Minto - Phase VI PFS) that is expected to start in the third quarter of 2011," said Brad Mercer, Vice-President, Exploration for Capstone.

Additional Mineral Resources by Class in the Wildfire/Copper Keel Region of MSD at a 0.5% Cu Cut-off Grade ("COG")**

*Rounded to nearest thousand; totals may not sum exactly due to rounding.

**Exclusive of all previous resources estimated for Area 2/118 deposit

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.

Minto South Deposit (MSD) - Mineral Resource Estimate

Geological modelling using new drill holes from 2010 and 2011 (partial) in the Wildfire/Copper Keel area indicate that Wildfire and Copper Keel are a southeast extension of mineralization located on the Area 2 side of the previous Area 2/118 resource model and not separate deposits as initially thought.  Approximately 134 new drill holes were added to the existing database of 235 holes to estimate a mineral resource for the entire MSD. These new data indicate a continuity of mineralization between Copper Keel mineralization and the deeper levels of Area 2. The new model indicates that there was also continuity of mineralization between Wildfire and the shallower levels of Area 2 before erosion removed mineralization and created the false impressions of a gap between the two deposits.

The 219 million pounds of copper gained in M&I resource class and attributable to the Wildfire/Copper Keel area of the MSD block model was determined by tabulating all mineralized blocks at the stated cut-off grade that lie outside of the southeast perimeter of the previous Area 2/118 block model.

The table below is a tabulation of all mineral resources by class for the combined Minto South Deposit at a 0.5% Cu COG.

Total Mineral Resources by Class for the Minto South Deposit at a 0.5% COG***

*Rounded to nearest thousand; totals may not sum exactly due to rounding.

***This tabulation includes mineral resources previous outlined for the Area 2/118 deposit.  For new mineral resources added by the new interpolation please refer to the previous table.

Total Undeveloped Resources for the Minto Mine

The following table details the total of all of the undeveloped mineral resources on the property at a COG of 0.5% Cu. The table includes Minto North, Minto East, Minto South and Ridgetop as listed form north to south. Any resources remaining in the Minto Main deposit are excluded because mining of this pit has been completed. Existing ore stockpiles are also excluded.  At the end of this news release is also a table of the undeveloped mineral resources for Minto at select copper COGs. Estimated grade and tonnage stated at copper COGs below 0.5% copper are for illustrative purposes only; to show the sensitivity of the mineral resource to changing copper COGs. Some of the estimated grade and tonnage at lower COGs may lie outside of any constraints imposed for "reasonableness of mining" purposes with respect to National Instrument 43-101.

Mineral resources at higher cut-off grades are for illustrative purposes and do not necessarily imply a higher potential for economic extraction. Only those mineral reserves determined by previous feasibility studies 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 anticipated to start in the third quarter of 2011 to apply economic considerations to the newly estimated mineral resources in the Wildfire/Copper Keel extension of the MSD.

Total Mineral Resources by Class for all Deposits Outside of the Minto Main Pit at a 0.5% Cu COG****

*Rounded to nearest thousand; totals may not sum exactly due to rounding.

****Excludes any resources remaining in the Minto Main Deposit, where mining as now ceased, as well as existing stockpiles of ore originating in the Minto Main Deposit.

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 m by 10 m by 3 m (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 1.5m 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 kriging method. Whereas the silver grades were interpolated using the inverse distance squared method only. Interpolated results are reported in measured, indicated and inferred categories and are based on continuity of the mineralization and sample density.

Minto South Deposit (MSD) -- Mineral Resources by Class at Select Copper Cut-offs

Minto South Deposit (MSD) -- Mineral Resources by Class at Select Copper Cut-offs - continued

*Rounded to nearest thousand; totals may not sum exactly due to rounding.

**Exclusive of all previous resources estimated for Area 2/118 deposit

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 ("NI 43-101") and reviewed by Brad Mercer, P. Geol., Vice President, Exploration for Capstone, the person who oversees exploration activities on the Minto Mine property.

The mineral resource estimate reported herein for the Area 2/118/Wildfire/Copper Keel deposit was estimated by Wayne Barnett, Pr.Sci.Nat. and Marek Nowak, P. Eng. of SRK Consulting. Dr. Barnett is the Independent Qualified Person under NI 43-101 responsible for the MSD mineral resource estimate and has reviewed the information in this release in respect of the MSD mineral resource estimate. The database used to estimate the Wildfire/Copper Keel deposit was audited by SRK. SRK is of the opinion that the current drilling information is sufficiently reliable to extend with confidence the boundaries of the mineralized domains from Area 2 into Wildfire/Copper Keel, and that the assaying data is sufficiently reliable to support estimating mineral resources. The mineral resources presented herein have been estimated in conformity with generally accepted CIM "Estimation of Mineral Resource and Mineral Reserves Best Practices" guidelines and are reported in accordance with Canadian Securities Administrators' National Instrument 43-101. Mineral resources are not mineral reserves and do not have demonstrated economic viability. In the opinion of SRK, the block model resource estimate and resource classification reported herein are a reasonable representation of the mineral resources at Wildfire/Copper Keel deposit at the current level of sampling.

With respect to the MSD mineral resource estimate, 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. 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, screen metallic assay method is used to determine the total gold content and gold content 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 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 Acme Analytical of Vancouver.

Cautionary Note Regarding Forward-Looking Information

This document may contain "forward-looking information" within the meaning of Canadian securities legislation and "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995 (collectively, "forward-looking statements"). These forward-looking statements are made as of the date of this document and Capstone Mining Corp. (the "Company") does not intend, and does not assume any obligation, to update these forward-looking statements, except as required under applicable securities legislation. 

Forward-looking statements relate to future events or future performance and reflect Company management's expectations or beliefs regarding future events and include, but are not limited to, statements with respect to the estimation of mineral reserves and resources, the realization of mineral reserve estimates, the timing and amount of estimated future production, costs of production, capital expenditures, success of mining operations, environmental risks, unanticipated reclamation expenses, title disputes or claims and limitations on insurance coverage. In certain cases, forward-looking statements can be identified by the use of words such as "plans", "expects" or "does not expect", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates" or "does not anticipate", or "believes", or variations of such words and phrases or statements that certain actions, events or results "may", "could", "would", "might" or "will be taken", "occur" or "be achieved" or the negative of these terms or comparable terminology. By their very nature forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Such factors include, among others, risks related to actual results of current exploration activities; changes in project parameters as plans continue to be refined; future prices of mineral resources; possible variations in ore reserves, grade or recovery rates; accidents, labour disputes and other risks of the mining industry; delays in obtaining governmental approvals or financing or in the completion of development or construction activities; as well as those factors detailed from time to time in the Company's interim and annual financial statements and management's discussion and analysis of those statements, all of which are filed and available for review on SEDAR at www.sedar.com. Although the Company has attempted to identify important factors that could cause actual actions, events or results to differ materially from those described in forward-looking statements, there may be other factors that cause actions, events or results not to be as anticipated, estimated or intended. There can be no assurance that forward-looking statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements.

Accordingly, readers should not place undue reliance on forward-looking statements.

SOURCE Capstone Mining Corp.