This report describes the work performed by the Pacific Northwest Laboratory and its subcontractor Battelle Columbus Laboratories on the Wire Rope Improvement Program during FY-1979 and the first half of FY80. The program, begun in 1975 by the US Bureau of Mines, was transferred to the US Department of Energy (DOE) on October 1, 1978. Since that time, the DOE's Division of Solid Fuels Mining and Preparation has sponsored the program. To address identified problems and provide information from which behavior of large-diameter wire rope could be better understood, efforts in the following areas were undertaken: large-diameter rope testing, small-diameter rope testing, data analysis and evaluation, wear and failure analysis, load sensor development, and technology transfer. Wire ropes 3/4 in., 1-1/2 in., and 3 in. in diameter were tested in bend-over sheave fatigue. Attempts were made to correlate fatigue life of these ropes. Limited field rope data were available to compare with test results. The modes of failure and wear in laboratory ropes were compared with those seen previously in field ropes. A load sensor was designed and ordered in FY79. It will be connected to the drag rope and jewelry of working draglines during the summer of FY80. Technology …