Well it seems as though I’ve managed to produce some useful research from my PhD so far. With the help of my co-authors and editorial support from the Scottish Journal of Geology I’ve published the findings of my initial modelling work.

I’m aware that not everyone is as immersed in the exciting world of mine  water heat as I am, so I’ve tried to summarise the research in a non-technical way. Have a wee gander below and if you have any questions get in touch!

Non-technical summary for: Coupled hydraulic and mechanical model of surface uplift due to mine water rebound: implications for mine water heating and cooling schemes

Heat available from mines

Abandoned mine workings underlie the majority of the towns and cities in Scotland’s central belt. The water in these mines is a potentially large source of heat located close to heating demand. I’ve calculated that the amount of energy available in these mines annually is equivalent to around 8% of Scotland’s annual domestic heating demand, which is lower than previous estimates. If more heat than this is extracted, “heat mining” will occur and the heat source will be depleted. One way to mitigate this is to use the mines as a heat battery, where excess heat could be stored for times when heating is needed. This excess heat could come from industry which requires cooling (e.g. data centres, commercial refrigeration) or seasonally in the summer when cooling is required instead of heating.

Surface uplift

If mines are going to be used as heat batteries it is important to understand how they respond to the associated changes in water level, temperature and pressure. It is quite complicated to link all these processes together so as a first step I’ve focussed on how water level changes affect the structural integrity of the mine and the overlying ground. During coal removal water was pumped out to protect the miners. Following closure of the collieries, this pumping has stopped and the water level is returning to it’s natural level. As the water level rises the overlying ground also rises slightly in response – termed “surface uplift”.

Model results

I’ve developed a numerical model* to simulate these processes (mine water level rise and surface uplift) which focusses on one layer of mine workings. I’ve used actual mine water level data from Midlothian, Scotland where mine water rose by just over 16m between 2015 and 2017. Surface uplift data (satellite data processed using InSAR) over the same time period indicates the land above the mine workings rose at a rate of 8mm/year. This equates to 1mm of surface uplift for every 1m of water level rise. My model results for the same water level rise over the same time period simulated 1.4mm of surface uplift for every 1m of water level rise.

The close relationship between the real and simulated surface uplift to water level rise ratio gives confidence in my modelling methodology. My model will now be developed further to understand the potential impacts of mine water heating schemes on the integrity of mine workings.

*This is basically software which undertakes all the complicated calculations for me!

First paper published! / De-risking mine water heat schemes by blogadmin is licensed under a Creative Commons Attribution CC BY 3.0