Environmental Consultant here. I would agree with what /u/Raligt has to say and would add that after a quick search online the stablisation works for the Crusader Avenue mineshaft were carried out by [Soil Engineering](http://www.soil-engineering.co.uk/case-studies/mine-shaft-stabilisation/). They have case studies online and it's probably worth a phone call to them to get their opinion. The info should be in the public domain as the work was carried out for the Coal Authority |