(Reuters) -Newmont said on Monday Tom Palmer will retire by the end of the year, in an unexpected move after spending more than a decade with the world's largest gold miner. Rival Barrick Mining also announced the sudden resignation of Mark Bristow as CEO earlier in the day. Bristow had led the Canadian miner for nearly seven years after its merger with Randgold Resources. Both Newmont and Barrick face a period of significant industry transformation amid these leadership shifts. Palmer will step down on ...