A crane lifts the Daly West Mine head frame out of a collapsed mine crater in Deer Valley. An upcoming lecture by geologist Brian Buck and Xcavation Company owner Clark Martinez will cover the head frame's collapse in 2015, and its remedial preservation efforts. Photo by Clark Martinez The Daly West Mine head frame collapsed on May 13, 2015, and geologist Brian Buck is going to tell people why during a free virtual presentation. In a discussion titled “When the Daly West Shaft Collapsed,” hosted by the Park City Museum and the Friends of Ski Mountain Mining History at 5 p.m. on May 5, Buck will recount the collapse, tell why it happened and talk about the remedial activities that occurred immediately afterwards.