Searching for a miracle in maze of mine tunnels 'In their opinion this remains a rescue mission, and there is still a chance for the boy'

Each time, the wet-suited members of the Mines Rescue Service dig deeper into the tunnels that criss-cross the ground, they have to step back and wait for pumps to drain the water that seeps in from all sides.

The water has made it all but impossible to use infra-red cameras to hunt for the body heat of the missing teenager.

He apparently disappeared after trying to rescue his dog from a hole which opened up in the cemetery as almost two inches of rain brought floods to central Scotland.

The searchers said yesterday they had not given up hope that the 18-year-old had found an air pocket.

The imminent arrival of a remote-controlled camera mounted on caterpillar tracks will bolster their search.

They said they had made good progress following a four-foot- high tunnel that would once have been used by miners hauling coal.

Two mechanical diggers have excavated a trench 70ft long and up to 25ft deep, exposing some of the old tunnels to daylight.

Barrie Jones, chief operating officer of the Mines Rescue Service, said: ''To be frank, the biggest problem is water and the fact that these are very old mine workings, and the uncertainty of those workings.

''There is no doubt this is work that has to be conducted very cautiously.''

It could turn out to be a mammoth operation. Old land records suggest the tunnels may extend for hundreds of metres. The network was dug to exploit the Kiltongue coal seam which comes close to the surface in the cemetery.

The nineteenth-century miners would shore up the tunnels with stone taken from the roof as they dug for coal.

But as more and more coal was extracted the roadways - as they are known - would join up, leaving more space than support.

Alan Grant, mining engineer with JWH Ross & Co, said that over time the action of water or the oxidation of coal could be enough to cause the roof to collapse.

Initially layers of rock above the workings would hold out but eventually successive levels can give way, causing a hole to migrate up towards the surface. If the workings are close to ground level, a sudden downpour can be enough for the ground to be swallowed.

However, Mr Grant said it was extremely rare for people to be hurt. ''These holes are not terribly common. It doesn't happen every day or every week but it will happen a few times a year,'' he said.

Inspector Les Gray, of Strathclyde Police, who is co-ordinating the search, said the specialist teams would ''work all night if it was safe to do so''.

He added: ''In their opinion, this remains a rescue mission and there is still a chance for the boy.''

He stressed that graves had not been disturbed during the excavations but said progress was also hampered by charts of the mines that dated from 1890.

While one family was praying for the safe return of their son, others had begun to get back to normal after the floods.

Andy Kerr, the Scottish finance minister, visited householders in the east end of Glasgow and promised an investigation into the cause of the floods.

However, he said that the executive and Glasgow City Council would not pick up the tab for those who had no insurance.

''As an executive and as the council, we can't be the insurer of last resort,'' the minister said after inspecting flood damage.

''But that is not to say we are heartless. We are looking to work with the social work department and the department of work and pensions to ensure that all the money that can be made available will be made available.''

The minister and Frank McAveety, deputy health minister, spent more than an hour touring the Greenfield area, where more than 57 families are still in temporary accommodation.

Many of the flood victims blame inadequate sewage or water drainage systems for the devastation. However, the council says drain cleaning work was carried out last month.