The Kamyr Ball Valve, METC SOA Test Valve No. A-17, accumulated 640 valve cycles in the Valve Static Test Unit and over 16,900 valve cycles in the Valve Dynamic Test Unit. During dynamic testing (with minus 8 mesh and 5/16''x 1/8''limestone), the stem packing was replaced twice and the valve was disassembled once to remove compacted fines from the body cavity. The seat leakage after testing was less than one-half of the rate allowed in the state-of-the-art project for a 6-inch valve. The inspection after testing showed sight abrasion and galling on the stem. With a suitable purge system to minimize the entry of fines into the stem packing and body cavity, this valve would be expected to have outstanding performance in lockhopper service with dry solids. Pilot-plant experience with a large valve (10-inch) from the same design series has shown that this design has the capability for a service life in excess of 10,000 cycles.