Concerns were heightened in the late 1980s after a roadwork contractor hacked through a section of the mines with a backhoe while excavating a trench. The then Bath City Council appointed a team, led by Dr Brian Hawkins, to investigate and map the mines following repeated accidents by utilities contractors and the increasing traffic over the mines area.Back to Top
The team also identified especially hazardous areas. The condition of the supporting pillars was examined and Dr Hawkins classified them 1 to 5 where 1 meant the lowest level of deformation and 5 represented the highest levels of deformation and deterioration. In essence, a classification of 5 meant that the pillar had failed and that it had minimal capacity to support the roof.Back to Top
A total of 3,737 pillars were surveyed with over 20% of pillars graded 3 to 5 which meant that they were deemed unstable with the remaining pillars considered unstable in the long-term. Nevertheless, given the potential domino effect which was likely to take place if one pillar collapsed, transferring the weight onto nearby pillars, even short-term stability of the mine could not be guaranteed for those pillars classified as 1 and 2. The conclusion was that the stability of the mines could not be guaranteed and a widespread progressive collapse could occur over a short time with extensive impact on life and property.
In 1994 Dr Hawkins completed a series of studies which identified the nature of the problem more fully. Only 1% of the solid floor was visible and roof collapses to within 3 metres of ground surface had taken place, some of which manifested themselves on the surface including collapses in the nearby golf course and rugby field and in people's driveways.
Following a visit in 2000, Her Majesty's Inspector of Mines (HMIM) recommended a series of safe access ways to be driven through the mines complex to determine the extent of remedial works required.Back to Top