Frontier exploration for mine water energy resources

Geophysical and geochemical techniques have been at the forefront of geoenergy resource exploration for more than 100 years. This paper aims to serve as a case study for how they have been used in conjunction with available data to investigate and characterize a mine water resource at the site of the former Comrie Colliery, in Fife, Scotland, which is undergoing redevelopment that will include a solar farm. Through a combination of desk study, near-surface geophysics, in situ monitoring of water level and temperature, and hydrochemical analysis, we outline potential options for mine water resource use, including heat extraction from and storage within the Comrie No. 1 Shaft. The key challenges included locating the shaft and identifying the source of water discharging from the site. These were respectfully overcome using electrical resistance tomography (ERT) to detect the targeted mine shaft and comparing the water composition from several sample locations to show that the water outflowing from a site drainage culvert had a large mine water contribution. Building on this, we estimate that the mine water resource has a capacity 2.23 MWth. Using heat extraction from the culvert alone, there is a capacity of 0.91 MWth. Our approach demonstrates how to successfully find a flooded mine shaft at a long-abandoned site with no identifiable surface features and comparatively poor data availability, delivering a methodological framework for mine water thermal projects facing similar resource characterization challenges elsewhere.