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Tri-Valley Unit Acquires Valley Sand & Gravel Assets

On Tuesday, September 13, 2005, Tri-Western Resources, LLC, a 50-50 joint venture operated by Select Resources Corporation, the minerals subsidiary of publicly traded Tri-Valley Corporation (AMEX: TIV), agreed to acquire the majority of the operational assets and equipment of Valley Sand & Gravel, located near Trona, California; the transaction being completed on September 19, 2005 with the transfer of funds.

The Valley Sand & Gravel operational assets and equipment include two gravel processing operations, including one dry and one wet (wash) plant, mobile mining equipment, stacker / conveyer sets, diesel generators, work offices, work-shop and other assorted equipment capable of producing 250 tons an hour.

Some of the equipment at the Trona site will be moved to Tri-Western Resources Basalt Quarry, located near Boron, about 65 miles to the south. The equipment to be moved includes excess stackers and conveyers, a Detroit diesel generation set, spare electrical equipment, 3 Mid-Western Screens, cones and storage bins, and other material handling equipment used in sorting crushed rock. Other equipment will be moved to Tri-Western Resources Monarch Calcium Carbonate Quarry, located approximately 50 miles to the west.

The Company is in its 43rd year of business as a successful operating company and for 32 years has been a full reporting 12 (g) publicly traded Delaware Corporation. Tri-Valley Corporation stock is publicly traded on the American Stock Exchange under the symbol "TIV" in the United States and is also traded in Europe on the Frankfurt Stock Exchange under the symbol "TVC WKN 911919." Our company websites, which include all SEC filings, are www.tri-valleycorp.com and www.tri-valley.de.

This press release contains forward-looking statements that involve risks and uncertainties. Actual results, events and performance could vary materially from those contemplated by these forward-looking statements which includes such words and phrases as exploratory, wildcat, prospect, speculates, unproved, prospective, very large, expect, potential, etc. Among the factors that could cause actual results, events and performance to differ materially are risks and uncertainties discussed in the company's quarterly report on Form 10-Q for the quarter ended June 30, 2005, and the annual report on Form 10-K for the year ended December 31, 2004.

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