학술논문

Combining ground stability investigation with exploratory drilling for mine water geothermal energy development; lessons from exploration and monitoring
Document Type
Academic Journal
Source
Scottish Journal of Geology. 59(1-2)
Subject
29A|Economic geology - energy sources
boreholes
chemical composition
Clackmannanshire Scotland
coal seams
D/H
discharge
Dollar Colliery
energy sources
Europe
fluid flow
geothermal energy
geothermal exploration
Great Britain
ground methods
grouting
hydrogen
isotope ratios
isotopes
Lower Coal Measures
mine water
mining
monitoring
O-18/O-16
oxidation
oxygen
pyrite
Scotland
seasonal variations
solutes
stability
stable isotopes
sulfides
United Kingdom
well completion
Western Europe
Language
English
ISSN
0036-9276
Abstract
Mine water geothermal's potential for decarbonisation of heating and cooling in the UK has led to increased national interest and development of new projects. In this study, mine water geothermal exploration has been coupled with ground investigation techniques to assess ground stability alongside seasonal mine water hydrogeology and geochemistry. Drilling operations in late 2020 at Dollar Colliery, Clackmannanshire, Scotland, encountered mined coal seams with varying conditions (void, intact, waste, etc.), reflecting different techniques used throughout a protracted mining history. We found that time and resources spent grouting casing through worked mine seams (ensuring hydraulic separation) can be saved by accessing deeper seams where those above are unworked. Continued assessment of existing water discharges and completion of boreholes with slotted liners into mined coal seams and fractured roof strata allowed chemical and water level changes to be monitored across a 1-year period. Mine water heads and mine discharge flow rates vary seasonally and are elevated between late autumn and early spring. The mine water has a low dissolved solute content. Dissolved sulphate-34S isotope data suggest increased pyrite oxidation during lower water levels. These findings can inform future building decisions, whereby housing developments on site could use the mine water for heating. Thematic collection: This article is part of the Early Career Research collection available at: https://www.lyellcollection.org/topic/collections/early-career-resear ch Supplementary material: https://doi.org/10.6084/m9.figshare.22188801