TORONTO, ONTARIO--(Marketwire - June 16, 2011) - Thundermin Resources Inc. ("Thundermin") (News - Market indicators) and 50% joint venture partner Cornerstone Resources Inc. ("Cornerstone") (TSX VENTURE:CGP) announce that a 25 hole, 12,690 m Diamond drilling program that commenced on the Little Deer Copper Deposit ("Deposit") on December 1, 2010 was completed on May 28, 2011. Assay results for the last 10 holes of the program are presented in Table 1 (see below). Results for the first 15 holes of the program were presented in news releases dated January 20, March 22 and April 26, 2011. The Deposit is located approximately 10 km north of Springdale in north-central Newfoundland.

The primary purpose of the current drill program was to increase the estimated mineral resources in the Deposit to the five to six million tonne range and to confirm the continuity of the copper mineralization in certain areas of the Deposit. The potential increase of the current mineral resources is conceptual in nature and it is uncertain whether the recently completed exploration drilling will result in an expansion of this mineral resource.

Holes LD-11-53, 54, 55 and 56, which were drilled to further define the eastern margin of the Deposit, all intersected variable amounts of copper mineralization over varying widths. Hole LD-11-57, which was drilled at depth along the eastern margin of the Deposit, intersected an extensive chlorite alteration zone but failed to intersect any significant copper mineralization.

Holes LD-11-58, 59, 61 and 62, which were drilled approximately on the -100 m elevation to confirm historical drill data in the upper central portion of the Deposit, all intersected variable amounts of copper mineralization over varying widths. The best intersections were 3.5% Cu over a core length of 2.9 m in hole LD-11-58 and 2.1% Cu over 6.0 m, including 8.6% Cu over 1.1 m, in hole LD -11-59. Hole LD-11-60 was abandoned due to drilling difficulties.

John B. Heslop, President and CEO of Thundermin, said "We are pleased with the overall results of the recently completed drill program as drilling continues to intersect good grade copper mineralization over mineable widths. We were also able to establish continuity of the copper mineralization in certain areas of the Deposit and have successfully reproduced copper grades and intervals in the area of the Deposit where we have recovered a large amount of historical information from the archives. We look forward to the completion of a revised National Instrument 43-101 ("NI 43-101") mineral resource estimate for the Deposit in the next couple of weeks".

P&E Mining Consultants Inc.

As announced on April 26, 2011, P&E Mining Consultants Inc. of Brampton, Ontario ("P&E") has been retained to complete an updated NI 43-101 compliant mineral resource estimate for the Deposit. This updated resource estimate will include results from 48,432 m of drilling in 82 holes completed by Thundermin and Cornerstone since June 2007 and all assay information from a total of 86 surface and 122 underground historical drill holes that were recovered from the archives of the Newfoundland and Labrador Department of Natural Resources. The historical holes were all drilled by British Newfoundland Exploration Company between 1961 and 1970. Additional details on the Deposit can be found in numerous Thundermin and Cornerstone news releases dated between May 1, 2007 and April 26, 2011 which are on each company's website and on SEDAR.

P&E has also been retained to complete an internal scoping review for the Little Deer project. This review will evaluate a range of potential mining and operating scenarios for the project and provide the management of Thundermin and Cornerstone with preliminary information on the economic viability of developing a new copper mine at Little Deer.

Mineral Resource Estimate

On October 13, 2010, Thundermin and Cornerstone announced that an updated NI 43-101 compliant mineral resource estimate had been completed by Scott Wilson RPA under the supervision of Mr. Reno Pressacco, M.Sc. (A), P.Geo., Senior Geologist for Scott Wilson RPA and an independent Qualified Person ("Q.P.") in accordance with NI 43-101. Scott Wilson RPA estimated that the Deposit contains Indicated Resources of 1,150,500 t at an average grade of 2.8% Cu within the Little Deer Zone and additional Inferred Resources of 1,227,300 t at an average grade of 2.2% Cu within the Little Deer Zone and 1,108,200 t at an average grade of 1.9% Cu within the Footwall Zone. An NI 43 -101 compliant Letter Report entitled "Mineral Resource Update for the Little Deer Project" dated September 30, 2010, to support the updated mineral resource estimate, is available on Thundermin's and Cornerstone's websites.

Metallurgy

On October 19, 2010, excellent metallurgical results from scoping level test work on core samples from the Deposit were announced. This work, which was undertaken at SGS Lakefield Research Limited ("Lakefield") of Lakefield, Ontario, indicates that a saleable, high grade copper concentrate grading over 28% copper with over 97% recovery and free of any deleterious elements can be produced from the Deposit.

Qualified Person

Mr. Andrew Hussey, P.Geo., Project Geologist and Lands Manager, Cornerstone Resources Inc., is the Q.P. responsible for supervising the drilling program and the compilation of all of the historical data on the Deposit for the purposes of NI 43-101. Mr. Hussey has also reviewed the contents of this news release for accuracy. All holes drilled by Thundermin and Cornerstone are NQ in size. Bulk density measurements, rock quality designations and photographic logging of significant mineralized intersections are performed systematically prior to assaying. The core is logged and the mineralized sections, where appropriate, are sawn in half at a core logging facility in Springdale. Half of the core is submitted for analyses to Eastern Analytical Limited, an independent and qualified assayer located in Springdale, Newfoundland and the remaining half of the core is kept for future reference. Blanks, duplicates and standards are routinely used as part of the assay procedures.

Little Deer Joint Venture

Thundermin, the operator, and Cornerstone have the option, on a 50/50 basis to earn a 100% interest in the Little Deer Copper Deposit and adjacent property from Weyburn Investments Ltd. Thundermin, under its joint venture agreement with Cornerstone, has the right to increase its interest in the Little Deer property to 75% by completing a feasibility study and by arranging 100% of the necessary bank financing required to place the property into commercial production. Details on the Deposit and the terms of the agreement with Weyburn can be found in numerous news releases and on Thundermin's and Cornerstone's respective websites and on SEDAR.

Junior Exploration Assistance Program

Thundermin and Cornerstone would like to acknowledge the financial support received from the Junior Exploration Assistance (JEA) Program of the Province of Newfoundland and Labrador in carrying out a portion of their work on the Little Deer property.

About Thundermin

Thundermin is a Canadian-based mineral exploration company focused on the exploration for and the discovery of economically viable base metal and gold deposits in Canada. Thundermin has an interest in, or the right to earn an interest in 11 base metal and gold properties in Canada. Thundermin also owns a 100% interest in the Lebel Township gold property, which is located on the Kirkland Lake Main Break in the prolific Kirkland Lake gold camp. Thundermin has royalty interests in 28 base metal and gold properties located in Manitoba, Saskatchewan, British Columbia and Quebec, the most significant being a 2.5% net smelter return royalty in the Pelletier Lake gold deposit which is under option to Alexis Minerals Corporation. Thundermin also has various shareholdings in thirteen other junior resource companies that are actively exploring for base metal, gold, chrome, vanadium -titanium and Diamond deposits in Canada.

Forward-Looking Statements

This news release may contain "Forward-Looking Statements" that involve risks and uncertainties, such as statements of Thundermin's plans, objectives, strategies, intentions and expectations. The words "potential," "anticipate," "forecast," "believe," "estimate," "expect," "may," "project," "plan," and similar expressions are intended to be among the statements that identify "Forward-Looking Statements". Although Thundermin believes that its expectations reflected in these "Forward-Looking Statements" are reasonable, such statements may involve unknown risks, uncertainties and other factors disclosed in our regulatory filings that can be viewed on the SEDAR website at www.sedar.com. For us, uncertainties arise from the behavior of financial and metals markets and from numerous other matters of national, regional, and global scale, including those of an environmental, climatic, natural, political, economic, business, competitive, or regulatory nature. These uncertainties may cause our actual future results to be materially different than those expressed in our "Forward-Looking Statements". Although Thundermin believes the facts and information contained in this news release to be as correct and current as possible, Thundermin does not warrant or make any representation as to the accuracy, validity or completeness of any facts or information contained herein and these statements should not be relied upon as representing its views subsequent to the date of this news release.