SURF crews complete stabilization project in the Yates Shaft

In 2021, crews at Sanford Underground Research Facility (SURF) completed an amazing feat: stabilizing a large section of the Yates Shaft in just six months. 

“Teams across SURF pulled together to make this happen—the shaft crews, engineering, operations—and still we supported science and excavation,” said Wendy Straub, director of hoists and shafts. “We did the work safely. We did it efficiently. There were so many things that came together to make this a success story.” 

This article explores the Yates Shaft, the work that was done and the teams that made it happen. 

The Yates Shaft 

The Yates Shaft was built by Homestake Gold Mine in the late-1930s. Unlike its twin, the Ross Shaft, which was lined with steel beams, the Yates Shaft was constructed with timber due to the scarcity of steel leading up to the second World War. 

A feat of engineering, the 5,140-foot structure is comprised of 803 stacked support sets that divide the shaft into three main compartments: the North and South cages, which transport people and supplies between levels; the North and South skips, which hauled ore from underground; and the Utility Compartment, which houses air, water, communication and power lines, as well as legacy piping. 

Today, the Yates Shaft is SURF’s primary access to the underground. The shaft conveys everything science needs to operate and provides access to science experiments and underground infrastructure. 

“Most mining shafts have a lifespan of about 50 years; it is because of the workmanship and ongoing maintenance that we are operational today,” said Syd DeVries, the senior principal engineer for building and site infrastructure for Fermilab’s Long-Baseline Neutrino Facility (LBNF). 

To ensure the longevity of the 81-year-old shaft, leadership developed a methodical construction approach called “top-down maintenance” in 2013. Top-down maintenance involves inspecting and grading every component of every set—timbers, posts, guides, bolting, lacing and turnbuckles—and making necessary repairs. 

“Data tells a story,” said Will McElroy, deputy director for operations. “When you have nearly 800 sets with so many individual components, you need data to inform your decisions.” This data guides infrastructure crews as they move from the surface and work their way down the shaft, set by set. 

Inspecting the Yates Shaft 

During a routine, weekly inspection on June 28, 2021, a member of the Yates Shaft crew noticed something amiss in the Utility Compartment: a piece of lacing, or protective timber, had come out of place. 

The crew removed the lacing to view inside the Pipe Compartment, a walled-off section within the Utility Compartment. From that vantage point, they saw that structural damage had occurred within the Pipe Compartment. “We found that a wall plate [a horizontal wooden beam] had been broken and that other components of the Pipe Compartment needed our attention as well,” Straub said. 

The crew issued a stop work order and stabilized the area. After comprehensive inspection, several concerns were discovered in the Pipe Compartment between the 1700 Level and the 2600 Level. The team shifted their focus from top-down maintenance in the Cage and Skip compartments to a concentrated stabilization effort in the Pipe Compartment. 

“It’s very important to note that it was our preventative maintenance and established procedures that identified this issue and brought it to our attention,” McElroy said. 

Undertaking stabilization

With this stabilization work at the top of their to-do list, regular Yates Shaft operations were paused temporarily and underground access was diverted to the Ross Shaft. “We shut down Yates Shaft operations to make sure we had dedicated time to make inspections and carry out repair work,” McElroy said. 

The Yates Shaft crew worked alongside SURF’s engineering and safety teams to establish a plan, then got to work. 

Early in the top-down maintenance efforts, the Pipe Compartment had been walled-off to ensure that no loose debris could enter the other compartments. When moving to a new set, the crews alleviated hazards, stabilized the work area, cleared out debris and built temporary work platforms. From the work platforms, crews removed and secured legacy piping, then replaced and restored timber and ground support. 

They repeated this process from late-June through mid-December. Between the 1700 Level and the 2600 Level, there are 149 support sets, many of which were slated to receive some restoration attention within the Pipe Compartment. In total, the crews removed 150,000 pounds of steel in the form of legacy pipe and replaced approximately 580 tons of timber. 

On December 16, after comprehensive inspections and safety reviews, the Yates Shaft pipe compartment stabilization project was complete. 

This video shows the interior of the Utility Compartment in the Yates Shaft, after the stabilization project was complete. Video by Adam Gomez and Matthew Kapust. 

Keeping science moving

Throughout this effort, SURF kept science moving. 

The Yates Shaft is typically dedicated to moving personnel and supplies for research in the Davis Campus, while the Ross Shaft is dedicated to the LBNF excavation effort. But for six months, crews and the majority of deliveries were managed solely through the Ross Shaft. 

This resulted in a massive coordination effort between SURF, researchers and contractors—coordinating cage times, blast schedules, access to experiments, transportation across the level, deliveries to the Davis Campus—all the while ensuring the safety of every person underground. 

For researchers at the Davis Campus, that meant 14-hour shifts underground from July through November, then a limited-access period of four hours per week in November and December. Jaret Heise, SURF science director, described the months as “feast or famine” for the research experiments at the Davis Campus. 

“During the feast, when we were working excessive hours underground, and the famine, when there was limited access, the research teams persevered—the path to keeping science going at the Davis Campus wasn’t an easy one to follow, but we made it work,” Heise said. 

In addition to the work by researchers, operations, engineering and science personnel directly supported activities at the Davis Campus, including upgrades to various liquid nitrogen systems to ensure experiment cooling and purging needs continued to be met. “I definitely want to thank everyone—every single person—who went underground during that period and helped science advance, because they really carried the effort through,” Heise said. 

The team that made it happen

“SURF relied on in-house talent throughout this restoration,” McElroy said. “Our expertise in engineering, planning and coordination, and execution of the work carried the project from start to finish.

Four rotating crews of Yates Shaft infrastructure technicians worked around the clock to push the effort forward. Members of the Ross Shaft and Underground Maintenance crews aided the effort in the Yates Shaft. Hoist operators volunteered to work overtime to ensure both Yates Shaft conveyances were staffed. The Ross Shaft crews worked to provide increased access to the underground. The engineering team drafted and vetted project plans. The science team worked with research groups to push science forward. Fermilab was instrumental in coordinating science access from the Ross Shaft station to the Davis Campus. Crews worked safely with continuous support from SURF’s Environment, Safety and Health team. 

Today, the Yates and Ross Shafts are again working in tandem to support operations at SURF. Weekly inspections, monthly surveys and top-down maintenance activities continue in the shafts. In the long-term, SURF is working on a plan to replace the Yates Shaft’s timber sets with steel infrastructure. 

“For the work that was done—the effort that was put in to create a plan, set a schedule and meet that schedule—these teams truly deserve a huge amount of recognition,” Straub said. 

Below are photos of three of the Yates Shaft crews. Not pictured: Russell Bauer, Jake Mack, Jim Nonnast, Will Hover, Rodney Loup, Charlie Roth, Dick Goetz, Brent Knottnerus (engineering support)

Left to right: Zak Mau , Pat Urbaniak, Casey Schaff, Dustin Mund, Mike Mergen. Photo by Wendy Straub.

 

Left to right: Juan Molina-Harris, David Schaffer, Dan Essink, Ashana Baumberger, Dustin Mund. Photo by Nick Hubbard

Left to right: Joseph Sigdestad, Ricky Allen, Michael Harvey, Alexis Novotny. Photo by Nick Hubbard