Combe Down and Bathampton Down Quarries (grid reference ST761625) make up a 6.22 hectare (15.37 acre) Site of Special Scientific Interest (SSSI) in Bath and North East Somerset, England, important for its bat population.

Combe Down forms a plateau capped by Great Oolite limestones between the valley of the River Avon and Horsecombe Vale.

[3] An underground survey of the Firs and Byfield mine areas was carried out in 1994, commissioned by Bath City Council.

[1] An Environmental Impact Assessment was completed for the stabilisation scheme and submitted to the Local Planning Authority in December 2002.

This highlighted that the mine is within the World Heritage Site of the City of Bath; adjacent to the Cotswold Area of Outstanding Natural Beauty (AONB); within a conservation area, containing a number of listed buildings; a Site of Special Scientific Interest; a candidate Special Area of Conservation; of international importance for Greater and Lesser Horseshoe bats; and of international geological importance, partly due to the work of William Smith.

A Bath and North East Somerset Council outline bid for a two-phase stabilisation project was accepted in August 1999, by English Partnerships who administered the programme for the then Office of the Deputy Prime Minister.

The work was largely complete by November 2009, by which time approximately 600,000 cubic metres of foamed concrete had been used to fill 25 hectares of very shallow limestone mine, making it the largest project of its kind in the world.