WorldWide Drilling Resource

Orphan Boy Mine Produces Heating and Cooling for Campus Building Compiled by the Editorial Staff of WorldWide Drilling Resource ® At Montana Tech of the University of Montana, water from a nearby mine is helping heat and cool a building on campus. The mine being used is the Orphan Boy, which was part of a larger silver mine built in Butte, Montana, in the 1900s. A huge slab of granite running thousands of feet into the ground separates it from a series of much larger, more famous copper mines nearby. As a result, the toxicity of the water is lower compared to the water in other mines, making it even safe for livestock to drink. Years of water pumping at the mine indicated the water temper- ature, which averages 78ºF (25ºC), was stable and suitable for long-term use. The purpose behind using the water as part of a heating system on campus was to demonstrate potential geothermal benefits to the surrounding city and other locations around the country. Montana Tech’s project at the Orphan Boy mine shaft is essentially a 50-ton ground source heat pump, which uses the mine’s warm water to heat and cool the school’s 56,000-square-foot Natural Resources building. Orphan Boy’s water temperature is distributed equally throughout the shaft, containing no hot or cold spots, which allows for more efficiency. The process involves a closed-loop system with 600 feet of plastic piping, extending down the shaft of the mine. The series of pipes make a loop 300 feet belowground and return 75-78ºF (24-25ºC) water to the surface. The facility pumps the water to a heat exchanger, where it’s warmed to 135ºF (57ºC) and can be used to either heat or cool the building. Heat pumps can produce 3-4 kilowatt-hours of thermal energy for every 1 kilo- watt-hour of electrical energy used to drive the heat pump. Shortly after completion of the project, data was collected which showed the heat pump delivered 88% of the annual heating needs for the Natural Resources building, reduced carbon diox- ide emissions by nearly 40%, and reduced the amount of money spent per year on utility costs by 40%. The project on campus has been a huge success. It shows how it can be economically viable to use water in a mine shaft to heat and cool a building. It’s an intriguing project for the city because Butte has hundreds of old abandoned mine shafts running beneath the streets, which are all filled with groundwater. However, the water was useless due to the contamination from the remnants of mining until this project provided a possible use. The question on everyone’s mind is, can the project be repeated on a larger scale for all of Butte, using the abundant mine water from the many copper mine shafts in the area. Many say it can work based on the University’s project, but the biggest problem being discussed is the needed infrastructure. The University had the foresight to build the Natural Resources building in preparation for the heat pump, so the building was already in close prox- imity to the mine shaft. However, trans- porting heat to buildings throughout all of Butte could potentially be an infra- structure nightmare. There are only a few examples of projects being able to tap into the geo- thermal potential of abandoned mine shafts. This project ranks as the only known example where heat exchangers were placed in a vertical mine shaft to use thermal currents. Donald Blackketter, Montana Tech’s chancellor and mechanical engineer by training said, “Where does it go from here? It’s like any kind of relatively new technology. I think it just goes incremen- tally along. People learn more and more about it. They can make fewer and fewer mistakes and make it work.” New & Used Bits, HDD Bits & Tools, Drag Bits & Wings, Bolt-On Drag Bits, Reverse Circulation Tools, Hole Openers, Claw Bits, Stabilizers, Subs, Custom Tooling & Welding, Hammer Bits, Drill Collars, Pipe Wipers, and Drill Pipe. Office: (661) 834-4348 Rod Henderson / Eran Henderson 661-201-6259 • 661-330-0790 sales@bitcobits.com www.bitcoinc.us 29 WorldWide Drilling Resource ® OCTOBER 2017