Thundermin and Cornerstone Announce a Significant NI 43-101 Mineral Resource for the Little Deer Copper Deposit,

TORONTO, ONTARIO, Jul 07 (MARKET WIRE) --
Thundermin Resources Inc. ("Thundermin") (TSX: THR) and 50% joint venture
partner Cornerstone Resources Inc. ("Cornerstone") (TSX VENTURE: CGP) are
pleased to announce the results of a National Instrument 43-101 ("NI
43-101") compliant mineral resource estimate for the Little Deer Copper
Deposit (the "Deposit") which is located approximately 10 km north of
Springdale in north-central Newfoundland. The mineral resource estimate
was completed by Micon International Limited ("Micon") of Toronto,
Ontario, Thundermin's and Cornerstone's independent resource estimate
consultants.

Micon has estimated that the Deposit contains 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 (see Table 1 and Figure
1).

Table 1: Micon Mineral Resource Estimate, July 7, 2009

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Resource Classification Tonnes (t) Copper Grade(%)
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Indicated 1,087,000 2.9
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Inferred 1,950,000 2.3
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Notes:
1. Assaying of drill core since 2007 by Thundermin and Cornerstone suggests
that the reported mineral resource may contain from 0.02% to 0.03%
cobalt. However, a reliable estimate of the overall cobalt grade for the
reported mineral resource is not possible at the present time as cobalt
was not consistently assayed on historical drill core.
2. An average dry bulk density of 3.06 tonnes per m3, as determined from
direct measurements from drill core, has been used for the tonnage
estimate.
3. In order not to distort the estimated grade of the Deposit with the
influence of extremely high grade copper samples, four copper assays from
two historical drill holes have been capped at 11.0% Cu. This capping of
high copper grades reduces the overall estimated grade of the Indicated
Resource by 0.03% Cu.
4. A copper price of USD $2.17/lb (being the 27 month London Metal Exchange
forward price as at June 1, 2009) and an exchange rate (USD/CAD) of
1.1 : 1 was used for the mineral resource estimate (copper price of CAD
$2.39/lb).
5. A cut-off grade of 1.25% Cu was used to construct a domain model of the
copper mineralization on cross sections spaced 50 m apart (+/-25 m
viewing windows).
6. The grade of the mineral resource estimate was determined using the
ordinary kriging method.
7. Mineral resources which are not mineral reserves do not have demonstrated
economic viability. The estimate of mineral resources may be materially
affected by environmental, permitting, legal, title, taxation,
sociopolitical, marketing or other relevant issues.
8. The quantity and grade of reported Inferred Resources in this estimation
are conceptual in nature and there has been insufficient exploration to
define these Inferred Resources as an Indicated or Measured Mineral
Resource. It is uncertain if further exploration will result in the
upgrading of the Inferred Resources into an Indicated or Measured Mineral
Resource category.

To view Figure 1: Longitudinal View, Little Deer Copper Deposit
Looking NNW, please visit the following link:
http://media3.marketwire.com/docs/thundermin707.pdf

The Little Deer mineral resource estimate was calculated using a database
containing 85 current and historical drill holes, 63 (30,800 m) of which
were drilled from surface between 1961 and 2009 and 22 (3,008 m) of which
were drilled from underground during 1968. The database includes all of
the holes drilled by Thundermin and Cornerstone up to and including holes
LD-09-22 and LD-08-16A, the results of which were released on June 16,
2009.

The mineral resource estimate was prepared by Mr. Reno Pressacco,
M.Sc.(A), P.Geo., Senior Geologist for Micon of Toronto, Ontario. Mr.
Pressacco is an independent Qualified Person ("Q.P.") in accordance with
NI 43-101. Mr. Pressacco has reviewed the contents of this news release
for accuracy. A NI 43-101 compliant Technical Report for the mineral
resource estimate is currently being prepared by Micon and it will be
filed on SEDAR within 45 days. Mr. Andrew Hussey, P.Geo., Project
Geologist and Lands Manager, Cornerstone Resources Inc., is the Q.P.
responsible for supervising the drilling program on the property for the
purposes of NI 43-101. Mr. Hussey has also reviewed the contents of this
news release for accuracy.

The Little Deer Copper Deposit is well situated to take advantage of
Newfoundland's developed infrastructure. The Deposit is located
approximately 16 km from the Trans Canada Highway and it is easily
accessible by a 10 km network of paved and gravel roads north of
Springdale, where there is an available skilled mining workforce. The
site is approximately 8 km from a major power transmission grid and there
is a plentiful supply of fresh water in the area. The Whalesback tailings
impoundment site, which may be able to be used to store additional
tailings, is located only 1,200 m north of the Deposit. There is also
reasonably good access to a deep water port for any future shipment of
copper concentrates. The Duck Pond base metal concentrator, which is
owned by Teck Resources Inc., is located approximately 165 km by paved
and gravel road from the Little Deer site, 66 km of which is on a
secondary paved road and 70 km of which is along the Trans Canada Highway.

To date, the Little Deer Copper Deposit has been intersected over a
strike length of approximately 1,050 m and to a vertical depth of
approximately 895 m. The Deposit remains open to the east, west and at
depth and the potential for discovery of additional mineral resources is
believed to be high (see Figure 1).

Diamond drilling on the Deposit is on-going and it is expected that two
new holes, designed to expand the reported initial mineral resource
estimate, will be completed as part of the $900,000 exploration program
outlined for the first half of 2009. Results from these holes will be
released once they have been completed and assays are received.

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 Little Deer
copper deposit and the terms of the agreement with Weyburn can be found
in news releases dated May 1, June 21, July 9, October 30, December 11,
2007 and January 24, April 9, May 15, June 6, June 17, July 25, November
26, 2008 and February 25, May 12 and June 16, 2009 and on Thundermin's
and Cornerstone's respective websites and on SEDAR.

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.

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.

Contacts:
Thundermin Resources Inc.
John B. Heslop
President & CEO
(647) 344-1167

Thundermin Resources Inc.
James W. Gill
Chairman
416-450-1851
info@thundermin.com
www.thundermin.com

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