The cave is covered by an unusual octagonal roof slab.

These have been removed and the openings infilled with a flat roof slab.

The roof slabs and walls are about 1 m thick, to bear load from all sides.

The firm continued work on in 2008 to restore the cantilevered south roof slab above the sanctuary of the temple.

Among other measures, the 8,700-pound roof slab had to be reset.

Rehabiliation of the station has included repairs to the roof slab and repaving.

Several large roof slabs had come down, bringing tons of broken rock with them.

The frame has a raked roof slab and circular columns.

Just fifty feet of dark void, all the way up to the underside of the roof slab.

Many of these roof slabs had a distinctive shape, pierced with a single hole to take a nail, were found on the site.