Borehole GGA02, UK Geoenergy Observatory, Glasgow

This report and accompanying data release describe the ‘as-built’ borehole GGA02 at the UK Geoenergy Observatory in Glasgow, as well as summarising an initial geological interpretation. Mine water borehole GGA02 at the UK Geoenergy Observatory in Glasgow encountered the Glasgow Upper and Glasgow Ell mine workings and was screened across an interval interpreted as a completely collapsed Glasgow Main mine working and overlying sandstone roof. Unfortunately, grout entered the inside of the casing in the final stages of borehole construction, cementing up the screened section and resulting in GGA02 being repurposed as a cased, sensor testing borehole. New sensors can be tested inside the uPVC casing to 67.2 m drilled depth. Hydrogeological testing of GGA02 was not possible. Borehole GGA02 has a number of types of sensor cabling installed. Fibre-optic DTS cable is installed between the bedrock uPVC borehole casing and the rock wall with capability to work in passive (monitoring) mode to 72.65 m drilled depth. Fibre-optic cabling is also installed on the outside of the steel superficial deposits casing with the ability for use in active or passive mode. Electrical resistivity tomography cable with the deepest sensor placed at 85.58 m drilled depth is available for cross-borehole monitoring and imaging with the adjacent borehole GGA01.