press release

Unocal unit intends to make conditional offer to purchase all outstanding shares of Northrock Resources Ltd.

El Segundo, Calif., April 10, 2000 - Unocal Corporation (NYSE: UCL) today said that its Unocal Canada Resources subsidiary intends to make a conditional offer of C$10.10 per share for the approximately 21.9 million shares (52%) of Northrock Resources Ltd. (TO: NRK) that Unocal Canada Resources does not already own. Unocal has proposed making this offer with the consent of, and in full cooperation with, Northrock.

Unocal Canada Resources currently owns 19.6 million shares (48%) of Northrock Resources Ltd. Unocal Canada Resources acquired these shares in transactions that closed in May and December of 1999.

The offer to be made for the remaining shares of Northrock will be subject to certain conditions including obtaining all required regulatory approvals and a minimum of 90% of the Northrock shares not already owned by Unocal Canada Resources being tendered to the offer.

Various conditions will have to be satisfied before the offer is made, including the Northrock board of directors recommending acceptance of the offer to the shareholders of Northrock Resources Ltd and consenting to Unocal Canada Resources making the offer, Northrock and Unocal Canada Resources entering into a definitive support agreement regarding the offer, and Unocal's board approving the making of the offer.

Unocal does not expect that the board of Northrock Resources Ltd. will decide whether to recommend acceptance of the offer until it has received and considered a valuation from an independent appraiser. Accordingly, Unocal does not expect to mail the offer documents to Northrock shareholders until early May.

Unocal is one of the world's largest independent oil and gas exploration and production companies with major operations in Asia, and the U.S. Gulf of Mexico, in addition to its interests in Canada.

Forward looking statements regarding commercial acquisition activities in this news release are based on assumptions concerning market, operational, competitive, regulatory, environmental, and other considerations. Actual results could differ materially as a result the foregoing and other factors as outlined in Unocal's 1999 Form 10-K report filed with the Securities and Exchange Commission.

Updated: April 2000