Pilot area activities – #10 Hydrogeological characterisation of abandoned mine workings for low-enthalpy geothermal in Glasgow, Scotland

Kirsty Shorter, 17 March 2020

Drilling, installation and testing of 12 boreholes

The British Geological Survey is currently constructing a geoenergy observatory in Glasgow, Scotland to provide an underground research facility to study abandoned mine water geothermal heating and cooling.  The works started in November 2018 with drilling of a stratigraphic rotary cored borehole to 199 m (102 mm dia. core) with installation of downhole seismic sensors, followed by open hole drilling of 11 further boreholes.  A series of wireline logs (gamma, caliper, sonic/cement bond) were run in the deeper boreholes, drill cuttings were collected from all open hole boreholes, with installation of temperature (DTS) and ERT cables on the outside of the casing of the mine water boreholes.  Six of the boreholes were screened over the mine workings, two in the bedrock and three holes were screened in the superficial deposits to enable environmental baseline monitoring of groundwater chemistry and water quality parameters.  Most recently, in early 2020, hydrogeological test pumping was undertaken on 10 boreholes (step-drawdown and constant rate).

Full details of this project can be found on the dedicated website: https://www.ukgeos.ac.uk/observatories/glasgow

Next steps will finalise well installations including CT2X data loggers (with monthly downloads), bladder pumps in seven mine water and bedrock boreholes, and submersible pumps in the three superficial boreholes.  The surrounding compounds will be installed with ground gas probes, near surface scanning lasers (for CO2 and CH4), InSAR reflectors, barometers and a weather station. We will also be starting a monthly groundwater sampling programme for the next year. During the sampling each month, field parameters of the water samples will be manually recorded, this includes pH, temperature, specific electrical conductivity (SEC), oxidation-reduction potential (Eh) and dissolved oxygen. Samples collected include organics (total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH) and volatile organic compounds (VOCs)); Inorganics, isotopes (C and O/H), organic carbon, Cr6+, NH4, and alkalinity measurements.

This project will contribute to MUSE by furthering our understanding of the geothermal potential of a mined system, providing new data and evidence for low enthalpy geothermal in a highly monitored system.

The Glasgow Observatory will be available for research in 2020 and access requests are currently being accepted.  For more information on how you might be able to use this facility please go to:

https://www.ukgeos.ac.uk/research or contact ukgeosenquiries@bgs.ac.uk

Maps of the UKGEOS Glasgow borehole locations, including detail of the mine water and environmental baseline boreholes at Cuningar Loop (in red box). Contains Ordnance Survey data © Crown copyright and database rights. All rights reserved [2020] Ordnance Survey [100021290 EUL]. Taken from (Monaghan, Starcher, & Barron, 2020)
Drilling boreholes and collecting rock chip samples during the drilling in summer/autumn 2019

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