MINE OVERBURDEN AND MINE WASTE AS A RENEWABLE ENERGY STORAGE PLAY

Various forms of mining in the US result in the excavation and movement of mass in excess of 5 Gt annually. This mass - be it overburden, waste rock, or mineral processing wastes (e.g., coal ash, tailings, slag) - currently provides mostly negative societal value because few valuable products are generated using it, and the mass is often considered an eyesore or an environmental liability.

We define Big Mass as mass ≥1 Mt that is moved across the Earth’s surface as part of some human activity. Further, we take for granted that Big Mass from mining will be generated into the foreseeable future within the US and global economies. We propose here a scheme that integrates Big Mass with other infrastructure to yield a device that provides potentially large positive societal value, a device for storing intermittent renewable energy such as wind and solar and releasing that energy on-demand to produce electricity. We call this device a Big Mass Battery, or BiMBy™ (Patents Pending) and we have studied two general BiMBy designs: 1) strip mine BiMBy, a device having relatively low thickness:width ratio of 1:20 or so (example 50 m : 1000 m; active Rosebud Mine, Colstrip, MT) and 2) open pit mine BiMBy, a device having relatively high thickness:width ratio of 1:7 or so (example: 200 m : 1600 m; inactive Anaconda Mine, Yerington, NV).

To be economically viable, a BiMBy device needs to be built at a huge scale. Such a device may easily have a map footprint of ≥1 km², a total mass of ≥100 Mt, and a renewable energy storage capacity equivalent to a 10-100+ MW power plant. As fossil fuels are phased out over the next decades, synergies between activities such as coal mining, fossil fuel-based electricity generation, renewable energy-based electricity generation, and BiMBy construction and operation could provide an economic lifeline for communities currently at risk because of heavy economic dependence on fossil-fuel extraction (e.g., Colstrip, MT). A BiMBy device has the potential to remediate some past mining sites (e.g., Anaconda Mine; Berkeley/Butte Pit) by transforming the mining sites into valuable, on-demand, renewable energy-based power plants.