Group looks at storing energy in old mine shafts
By LISA BOWERS
Journal Staff Writer
NEGAUNEE — The July 26, 1979, closure of the Mather B Mine in Negaunee marked the end of an era.
It was the last of the underground iron mines to operate on the Marquette Iron Range, but if a Michigan Technological University study bears fruit at the end of June, the mine could usher in the beginning of a new one.
The pilot study, conducted by the university in collaboration with the city of Negaunee and WPPI Energy, will determine if abandoned mines can be profitably turned into utility-scale batteries, storing “green” energy for consumers on the electrical grid.
The Mather B was chosen, in part, because it has characteristics the research team determined a mine must have to provide underground pumped hydroelectric storage: both flooded and not flooded levels; enough water volume for utility-scale hydro storage; enough capacity for the hardware, such as turbines and pumps; and “robust underground structure.”
Timothy Scarlett, MTU associate professor of archeology and anthropology, said in an email Wednesday that a research team, consisting of MTU faculty and graduate students, toured the site of the abandoned mine earlier this month in order to gather information.
“Our team toured the site of the Mather B, walking the grounds of the Negaunee High School (which reused the old Mine’s dry house) and the city-owned property around the mine ruin,” Scarlett said. “The faculty and graduate students can really understand the site now as they think about the project’s potential.”
The team also held a public forum attended by about two dozen area residents who seemed “universally enthusiastic” about the project, said Roman Sidortsov, MTU assistant professor of energy policy, in a Wednesday email.
Negaunee Planning and Zoning Administrator David Nelson said while members of the public did express some concerns during the forum, the researchers were able to set them at ease.
“It was more explaining to the public how the actual system would work, the geological stability of the shaft itself and making sure that everybody understood that this is technically a pre-feasibility study,” Nelson said. “It’s at the extreme early stages. But that being said, Michigan Tech also plans on expanding out from this — if they do end up getting more funding for it — to possibly look at a nationwide feasibility of … using this technology in any one of the thousands upon thousands of mine shafts that exist throughout the country, and use that to stabilize the (electrical) grid.”
He said research was also conducted at the Cliffs Shaft Mine Museum, which has an archive and a large collection of historic documents from the Cleveland Cliffs Mining Co., including mine maps showing levels and sublevels of the Mather B mine during the 1950s and 1960s.
“A group of retired miners joined Mr. (Craig) Ilmonen for the day, talking with us and our students about the Mather B,” Scarlett said. “We looked at historic mine maps that helped us understand the mine’s structure and geology, which will directly inform our calculations in the case study — things like construction cost estimates, historic water drainages and potential energy.”
Basic knowledge of how the system would work is helpful in order to understand the importance of the maps to the study, he said.
“An underground pump hydro storage system’s potential energy — the capacity of the battery is dependent upon how far the water drops from the upper reservoir to the turbine, in this case the deeper the mine, the better, and the number of and size of the turbines, in this case limited by the size of the mine shafts in which the turbines would be installed. The maps show these details,” Scarlett said.
The total volume of water stored in the system will determine the length of time the turbines can produce power, he said — the more water the mine can hold, the longer the storage facility can produce the power.
Once the team has detailed digital scans of the maps, students can create a highly accurate 3D model of the mine for calculations.
Negaunee City Manager Nate Heffron said there is great potential in the project.
“From my perspective as the energy provider, I feel that we have several possibilities that could come out of this project,” Heffron said. “We have the potential of lowering energy costs. We have the potential to sustain a local and reliable energy source. We have that now, but the ability to store it here is very beneficial to us, I think. We are forging forward on the next generation of energy production, and that’s green energy.”
The researchers would like to involve Negaunee High School students in the next phase of the study, Scarlett said, which could include sending an underwater autonomous vehicle into the shaft to survey it.
“We talked about the idea of involving them in several ways, from robotic survey to water quality chemistry,” Scarlett said. “But until we talk to the teachers, we can’t say what might happen.”
Lisa Bowers can be reached at 906-228-2500, ext. 242. Her email address is firstname.lastname@example.org.