During 2021, KETL team member Jacob Chizek built a three dimensional solid model of the Negaunee's Mather mine, facilitating our detailed design and analysis of a PUSH system. The model was important for many reasons, but most importantly, Jacob's work let the team create more precise estimates of the mine's size and form. The increased precision made all of the other PUSH study better because the team members could work from very realistic estimates of the mine's size, capacity, and layout.
Jacob started his work with skills in computer modeling, particularly CAD and SolidWorks, but he'd never done anything like this before. He wanted to make a three-dimensional solid model of the Mather Mine using engineering maps from the late 20th century (1960s-1980s). This model would then provide accurate volumetric estimates. Like most mechanical engineering students, Jacob had worked up 3d drawings of objects before, but always 'widgets' that he'd imagined himself. This job required that he start by tracing digital maps of a real 3d environment, import those sketches and overlay them at the correct scale, then add volumes overtop of the flat plots.
Jacob started his work using a mosaic of snapshots that research team members made of historic maps in the collections of the Cliffs Shaft Mine Museum in Ishpeming and the Michigan Department of Environment, Great Lakes, and Energy's Oil, Gas and Minerals Division Upper Peninsula Geological Repository archive in Gwinn, Michigan. While this project did not allow for formal digitization of all the underground maps, by working between a few critical maps drawn at different times to different scales, supplemented using detail from the largest maps, he built a 3d model that captured the extent of the underground workings.
The model provided more precise measures of the volume of water in the flooded mine's different levels, which the team then used to compare different models for energy storage design.
At the same time, the model also helped the team visualize different design options. How big of a turbine can fit into the Mather B's shaft? What if we designed the system to pull water up the Mather A shaft, then drop it down through a turbine and into the lower reservoir through the Mather B shaft? What if we used the entire mine as a the lower reservoir and built a surface pond? What if we designed a very small system, using only the Mather B shaft?
Because he could geolocate his underground model, connecting it to the surface, we could also visualize the relationship between the under- and aboveground features, including existing power lines, streams and waterways, buildings, and other area mines.
When the team held a public meeting to share a preview of their findings with the residents of Negaunee, Mr. Chizek shared his model with the audience, including some veteran miners from Mather's operating days. As one might predict, the model was very popular! people stood around the large monitor, sharing stories and talking about things they remembered, places they'd been underground, and those areas they'd never seen.
Jacob’s modeling work enables additional technical analysis (heat transfer, water flow, volume/capacity, etc.) for systems like geothermal HVAC, Low-differential geothermal power, aqueous mineral reclamation, etc. At the same time, his models also support a range of SciComm activities, perhaps allowing the Cliffs Shaft Museum to create an exhibit or video, aiding planning by the cities of Negaunee and Ishpeming, and enriching public interactions on social media. We will see what develops!
The next step in this process might be to create an ultra-high scale model of the mine workings. That would require the quality digitization of hundreds of large-scale maps held by EGLE and the Cliffs Shaft Museum, then hundreds of person-hours of time tracing and building the model. This would result in the the most detailed model possible without draining the mine to complete a modern survey of current conditions. However, an Enterprise Team at Michigan Tech has started brainstorming on an underwater ROV that could remotely scan and map old flooded mines, building a new 3d model of current conditions without the expense and environmental risk of pumping the mine dry or risking human lives through survey. Autonomous underwater survey robots would be very powerful tools for PUSH design, but are still mostly science fiction. Jacob's model is an excellent resource for the team and provides all a research team needs to evaluate PUSH potential in a given location. If organizations move to begin planning a real facility, then the best possible model will become an important tool!
Jacob Chizek is an undergraduate student studying Mechanical Engineering at Michigan Technological University. His contributions were initially supported by our grant from the Alfred P. Sloan Foundation (grant number G-2018-11305) and continued thanks to a Student Research Grant from Michigan Tech's Great Lakes Research Center. Jacob is interested in grid scale energy storage solutions and found this modeling exercise gave him time to imagine other potential innovations for energy storage in flooded and abandoned mines. He is also a member of MTU's Supermileage Systems Enterprise, where he works on the engine subteam.
Editorial update: People asked, so I thought I would mention these facts here:
Our study case study in Negaunee, Michigan, showed that the mine could be ultra-long duration storage, providing continuous power to 30,000 people for 3.5 months--at a profit--once it is built.
Based upon how it was designed, if the Mather B was a hydropower station, it would be among the largest facilities in the world. It is a battery, however, not a generator!
Our team's geospatial analysis shows about 1,000 possible sites for grid-scale PUSH facilities in the United States, with enough energy capacity to meet the projected national needs for storage.
Perhaps more importantly, it is in the public's interest to solve all these problems--energy storage, mine reclamation, rural economic development, energy justice-- using the energy transition as an opportunity to bring a sustainable economic resource to communities that have been abandoned by mining, as they struggle with reclamation and revitalization.
The report is downloadable here.