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.

“As the title of the talk suggests, the main thesis will be to describe what happened,” said Buck, who holds a master’s degree in geological engineering from the University of Utah. “And then we will lead up to the current condition of the site.”

The “we” Buck mentioned is himself and Clark Martinez, owner of Xcavation Company, a Park City-based corporation that capped the Daly West shaft after its collapse.

“I’m so thrilled to have Clark coauthor this discussion with me,” Buck said. “His company is widely known for closing, stabilizing and reclaiming mine sites in and around Utah and the adjoining states for many years.”

Martinez, a Park City High School graduate, is also a fourth-generation miner, according to Buck.

“After he graduated he got work with Park City Ventures, and they reopened the Ontario Mine in 1976,” he said. “He also worked in the Keetley tunnell and the Snake Creek tunnel, that runs from Heber to the former Judge Mining property.”

The two will discuss the Daly West’s situation by using some of Martinez’s photos, some of which haven’t been seen by the public, Buck said.

“I’m thrilled Clark agreed to share his story from his company’s files,” he said. “We have some good stuff to share regarding how things look and what has been done.”

In order to explain why the head frame collapsed, Buck and Martinez decided to start the lecture with a segment about how mine shafts are sunk and built.

Park City’s Daly West Mine, located near where the Montage Deer Valley now stands in Empire Canyon, was a premium example of lead and silver mining operations during its heyday in the mid- to late-1890s, Buck said.

“When the shafts were first sunk, the supporting structure was timber,” he said. “Miners used timber framing to provide the structural support for air lines, guides for the cages and skips, and the pumping lines for the water. All of these things were attached to the timber.”

In addition, the timber provided support for the ground that wasn’t solid rock, Buck said.

“The problem is that timber doesn’t last forever,” he said. “As the boards grew weak and began rotting, mines had to replace them, but once the mining companies abandoned the shafts, the maintenance stopped.”

The lack of maintaining the rotting timber supports was one of the reasons the Daly West head frame collapsed, but it didn’t collapse at once, according to Buck.

“There was a partial fail in 2012, which Clark’s company stabilized, and then in 2014, another part of the shaft started to collapse,” he said. “The problem was this happened in the fall, and winter was right around the corner, which prevented stabilization work other than covering the crater until the spring.”

Martinez signed the contract to stabilize the shaft on May 12, 2015, but the head frame collapsed the next day, before he could do any work, Buck said.

“We’ll talk about that, and then the rest of our presentation will be about the current stabilizing efforts,” he said.

The other thing the two will address is the new plans to repair the 45-ton head frame.

“Deer Valley, Park City Municipal and the Empire Pass Master Owners Association are all collaborating together to lift the head frame, fix its feet and reerect it on a sight that is close to the original shaft,” Buck said.

Buck and Martinez will close the discussion by mentioning the Silver King Coalition shaft and the Thaynes shafts, which are also in danger of collapsing.

“Friends of Ski Mountain Mining History have plans to do some studies and remedial work to prevent those shafts from falling like what happened to the Daly West,” Buck said. “But that discussion is another story.”