PolyMet Mining Corp. announced that Richard Lock, a veteran mining executive who has led construction and development of large copper and other mines around the globe, has joined PolyMet as senior vice president and project director for the NorthMet Project. Mr. Lock most recently was construction director for the KAZ Minerals Peschanka open pit copper mine located in Russia, within the Arctic Circle. Previously, he held executive and project director roles at Arizona Mining Inc.'s Hermosa project, a lead-zinc-silver mine in southern Arizona; Yara International's Dallol project, a sulfate of potash mining project in Ethiopia; Western Potash Corporation's Milestone project, a potash solution mining project in Canada; and Rio Tinto's Resolution and Keystone copper projects in Arizona and Utah, respectively. Earlier, Mr. Lock held leadership roles in the development of Canadian Natural Resources Limited's Horizon oilsands mining development in Alberta, and Rio Tinto's Diavik diamond mine in Canada's Northwest Territories. Unrelated to Mr. Lock's appointment and for personal reasons, Dennis Bartlett retired from the PolyMet board of directors, effective December 31, 2019. He joined the board in 2017.