No. 86-7387. Argued and Submitted March 9, 1987. Decided August 6, 1987. John Welsh, Washington, D.C., for petitioner. Patricia S. Radez, San Francisco, Cal., for respondent. On Application for Enforcement of an Order of the National Labor Relations Board. Before FLETCHER, BEEZER and THOMPSON, Circuit Judges. PER CURIAM: The National Labor Relations Board (the Board) petitions for enforcement of its order requiring Yuba Natural Resources, Inc. (Yuba) to bargain with Operating Engineers Local Union