SAFETY fears at the National Coal Mining Museum have led to the closure of its underground tour.
Directors say water could be present in a nearby old coal seam and although there is no imminent threat of flooding, the tour is being closed until further notice.
It is the second time in the prestigious museum's history that the former Caphouse Colliery at Overton, between Grange Moor and Wakefield, has been closed to the public. It was shut in 1997/98 for 10 months.
Richard Saward, commercial director, said: "This is a blow, particularly in the light of the advances made over the last two months and the planned developments for the year ahead.
"We overcame a similar problem in the past and are confident we can do it again."
The closure was prompted after routine data collected through a borehole monitoring system suggested water may be present - and could threaten the underground attraction.
Further investigations are needed and trips down are suspended until further notice.
A £6.5m redevelopment of the surface galleries and attractions was finished in April 2002.
The museum is open all year round from 10am to 5pm except for December 24 to 26 and January 1.