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TORONTO, ONTARIO--(Marketwire - July 13, 2010) - Thundermin Resources Inc. ("Thundermin") (TSX:THR) and 50% joint venture partner Cornerstone Resources Inc. ("Cornerstone") (TSX VENTURE:CGP) announce that they have extended the option with Weyburn Investments Limited ("Weyburn") to earn a 100% interest in the Little Deer copper deposit (the "Deposit") located approximately 10 km north of Springdale in north-central Newfoundland.

Under the terms of the agreement with Weyburn, in order to extend the option beyond the third anniversary of the agreement, Thundermin and Cornerstone agreed to pay Weyburn a total of $200,000 ($100,000 each in cash and/or shares at each company's election) on or before July 12, 2010. Thundermin elected to issue 840,336 shares, at a price of $0.119 per share, and Cornerstone elected to issue 684,932 shares, at a price of $0.146 per share. These payments will maintain the option on the Deposit in good standing until July 12, 2011. Further details on the terms of the agreement with Weyburn can be found in a news release dated May 1, 2007 and on Thundermin's and Cornerstone's respective websites and on SEDAR.

Diamond drilling programs undertaken since July 2007 have greatly expanded the known copper mineralization within the Deposit. On July 7, 2009, Thundermin and Cornerstone reported a National Instrument 43-101 ("NI 43-101") compliant mineral resource estimate for the Deposit comprising Indicated Resources of 1,087,000 tonnes at an average grade of 2.9% Cu and Inferred Resources of 1,950,000 tonnes at an average grade of 2.3% Cu. The mineral resource estimate was prepared by Mr. Reno Pressacco, M.Sc.(A), P.Geo., for Micon International Limited ("Micon") of Toronto, Ontario, an independent Qualified Person ("Q.P.") in accordance with NI 43-101. An updated NI 43-101 mineral resource estimate, based on drill hole results subsequent to the July, 2009 estimate, is anticipated later this summer once final results from the current 11,000 m drill program have been received.

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 has royalty interests in a further 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 that is currently the focus of underground work by 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.

For further information on Thundermin Resources Inc. please visit Thundermin's website at [ www.thundermin.com ] or the SEDAR website at [ www.sedar.com ].