Geothermal Mining Prospector

– Led Opportunity Assessment of Geothermal Mine Water Systems in Canadian Inactive Underground Mines –

Situation

In 2006, the Mining Association of Canada and Natural Resources Canada (NRCan) commissioned a study to assess the opportunities for extracting geothermal energy from inactive underground mines in Canada and using the heat for space- and water-heating in surface buildings.

Over two centuries of mining in Canada have left thousands of underground mines that are no longer used but are still largely intact. With increasing energy prices, price instability, and the focus on energy independence, it may make sense to extract geothermal energy from some of these underground workings and use it to heat nearby buildings. The idea might sound far-fetched, but it has been around for decades and has many benefits for the community and the environment. Upon closure of a mine, turning it into a renewable geothermal energy source provides a welcome parting gift to the community and can improve a mining company’s public image.

Actions

FVB Energy prepared a technical description and design considerations for geothermal heat pump systems and district energy distribution of the extracted heat.

I led the entire assessment of Canadian underground mines:

  • Reviewed world-wide experience in operational geothermal mine water systems
  • Extracted the design considerations for the application of using inactive underground mines for geothermal systems
  • Secured and analyzed provincial and territorial mining databases to estimate the number of sites in Canada that were technically suitable for such systems; I used the following five criteria for technical suitability:
    • Depth of at least 30 metres as a proxy for sufficient mine water temperature
    • Extensive underground workings as a proxy for size and renewability of the geothermal reservoir
    • Closed after 1950 as a proxy for mine workings in good condition and availability of accurate mine data
    • Located near potential end-uses to minimize the cost of insulated pipe
    • Low possibility of re-opening to ensure long-term project financial viability
  • Assessed the technical and financial preliminary feasibility for two specific Canadian sites, including legal/regulatory, environmental, and socio-economic impacts for these sites
  • Estimated the potential greenhouse gas emission reductions

Outcomes

Based on the limited data on these thousands of mines and their nearby communities, I found 25 sites that met the screening criteria above, with the potential to reduce 10 kilotonnes of carbon dioxide equivalent per year (ktCO2e/yr) of greenhouse gas emissions. The remaining thousands of sites were too shallow, small, old, or remote, based on the best data at the time.

I presented the results in:

  • 2006 to the MAC Energy Task Force and NRCan
  • 2009 at the Energy 2009 industrial energy efficiency conference, alongside Ralph Ross – the lead technical consultant for the Springhill, Nova Scotia geothermal mine water system
  • May 2010 articles in Canadian Consulting Engineer magazine and Canadian Mining Journal