Boulders the size of 'filing cabinets' put out of danger

Published on Monday 29 September 2008 09:59

UNSTABLE boulders the size of "filing cabinets" are being removed from Salisbury Crags in an emergency operation to prevent rock falls.

Expert engineers, archeologists and conservation workers have been carrying out the work for the past week, chipping off loose material to protect passers-by from its potential impact.

The specialist procedure, which is costing tens of thousands of pounds, was prompted by the discovery of fallen rock by pedestrians earlier this summer.

Historic Scotland's Martin Gray said: "The team has been removing anything that's loose or looks like it could become loose.

"There have been a lot of large pieces – some the size of filing cabinets – and other smaller bits, more like footballs.

"This is nothing for the public to worry about, though – it's a totally natural process."

Rocks regularly fall from the landmark, but this summer's wet weather is thought to have increased the occurrence, causing concern to experts about the safety of walkers in the area.

Falling rocks are caused by the elements – water which gets into cracks will naturally freeze, gradually causing them to expand and break.

Mr Gray, one of the rangers in charge of the Crags, said: "It is often a case if surrounding grass is particularly wet, it is enough to move the rock, causing it to fall."

Motorists have been unable to pass the Crags for over a week after an emergency meeting of specialists advised a road closure during the works programme. Experts allow the removed pieces of rock to fall as they are worked on, leaving them where they land.

Passers-by have been seen watching from a distance as the team of three climbers and four banksmen work on the Crags.

Motorists have also voiced frustrated at the prolonged closure of the road, which may remain shut for another week.

Mr Gray said: "Everybody has a right to moan. I am sure they don't think we closed the road because we felt like it though, it's because we were concerned."

Salisbury Crags is described by geologists as an "intrusion," developing from the ground 65 million years after Arthur's Seat, which is 350 million years old.

Experts believe the Crags "came up from the ground" due to a tilt in the earth. There is geological evidence that people lived in settlements at the top of the landmark during the Iron Age.

Mr Gray's team regularly checks the area for fallen rocks and it is hoped this procedure – the first of its kind – will prevent the need for further work for many years.