A LEADING geologist has been describing how a wall of water has frustrated attempts to uncover so-called "hot rocks" near a redundant cement plant in the North Pennines.

But he forecast that the French-owned drilling rig - nicknamed "the space station" by local people - would strike an energy-giving vein of green granite in Weardale, County Durham, in the next two weeks.

Professor Paul Younger, who is leading the £400,000 study near the Lafarge cement works (formerly Blue Circle) at Eastgate, said they would then have a much clearer picture of the geothermal qualities of the granite.

Prof Younger, of the civil engineering and geo-sciences department at Newcastle University, who was addressing a public meeting organised by the Friends of Killhope mining museum, said his team had been taken by surprise by how quickly events had moved since they started drilling six months ago.

But they had been frustrated by masses of groundwater they had met, which had gradually slowed down drilling. It had also made the geothermal signals they were getting unclear.

He said the borehole, near the site of the old Cambokeels mine, was only the second to be drilled in Weardale - the first was at Rookhope, in 1961.

"We believe there is more than an evens chance of harnessing geothermal energy from this site for use on the Eastgate site when it is redeveloped," he said.

"That would be like a gift from God, because the recovery costs are negligible when compared with other energy sources."

But Prof Younger admitted it was less certain that the heat-producing quality of the granite would allow it to be exported to a wider area.

He also revealed that the drilling team had discovered a warren of "really weird" large caves, which had been completely filled with clay some time in the past.

They were lying under a field of large boulders just under the surface.

The search for "hot rocks" at Eastgate is being funded by regional development agency One NorthEast and the French-owned Lafarge cement conglomerate.