
    Argued December 15, 1977,
    affirmed January 16, 1978
    POWELL, Appellant, v. EDWARD HINES LUMBER COMPANY, Respondent.
    
    (No. [ A XXXX-XXXXX ], WCB 76-876, CA 8939)
    572 P2d 1335
    Neis Peterson, Portland, argued the cause for appellant. With him on the brief was Peterson, Peterson & Peterson, P.C., Portland.
    Scott M. Kelley, Portland, argued the cause for respondent. With him on the brief was Gearin, Cheney, Landis, Aebi & Kelley, Portland.
    Before Schwab, Chief Judge, and Thornton and Joseph, Judges.
    PER CURIAM.
   PER CURIAM.

In this worker’s compensation case the primary issue is a factual one — did claimant prove by a preponderance of the evidence that his original compensable back injury had been aggravated? We agree with the triers of fact below that he did not.

Affirmed.  