Landslide knocks line out for at least two months
Owners of a south Yorkshire colliery were this week facing a substantial compensation claim from Network Rail after it emerged that a landslip had closed a key section of railway for at least two months. A pile of colliery waste suffered a rotational and translational failure twisting the line vertically and horizontally.
The effect of the landslip at Hatfield Colliery was first noticed on 9 February when a train driver on the Doncaster to Goole line reported a “rough ride” through the area. Network Rail started to monitor the situation before suspending rail services on 12 February.
The slip worsened considerably over the following 24 hours leaving the trackbed heavily deformed.
Network Rail said that it will take eight weeks to repair the damage to its track once Hatfield’s owners have remediated the collapsed spoil heap embankment. In the meantime, passengers are using a replacement bus service.
But mining company Hargreaves, which is managing the site, told NCE this week that it had still to work out a recovery plan. It wants to let the slip settle naturally before attempting any remedial work.
Hatfield is currently owned by a group of banks that is owed money by previous owner Powerfuel which went into receivership two years ago.
Hargreaves operates several of its own collieries in the North East, and expressed surprise at the slip. The spoil heap is up to 30m high and has been built up over a number of years, but is no higher than other spoil heaps on the site that show no sign of movement.
“As far as we know, there have not been any major stability problems at Hatfield in the past, although minor ground movements are common in most spoil heaps,” said a Hargreaves spokesman. “Some other spoil heaps on the other side of the Hatfield site are up to 40m high and show no sign of stability problems.”
The spokesman confirmed that Hargreaves is working with external civil engineering consultants to find a solution for the site but declined to name which companies are involved.
The Health & Safety Executive has accepted the consultants’ advice to allow the collapse to settle naturally and reach equilibrium before starting remediation work.
“The movement is being monitored around the clock and this suggests that the slope is reaching a stable situation,” added the spokesman.
“Once the slope has stabilised we will be designing a major earthworks programme, but it is not clear at this stage whether this work will focus solely on the collapsed section or extend to the rest of the spoil heap adjacent to the railway,” he said.
“We hope to have a clearer picture by the end of the week.”
Images of the landslip have been analysed by Durham University Wilson professor of landslides Dave Petley who believes heavy rain and the local geology may have played a part in the collapse.
“It would be surprising if the heavy rainfall levels we have seen over the last year were not a factor,” he said.
“It is an interesting landslide with both rotational and translational failures.”
“The local geology maps show that the tip has been constructed over a layer of alluvium and I believe that the failure started in this layer,” he added.
“This lead to the ground under the railway moving forward as the heap shifted downwards.
“The toe of the landslide is now acting as a counterweight to the main slope.” Petley suggested that any earthworks will have to start from the top of the slip. “It will be a challenging remediation,” he added.
A bus replacement service is currently running between Doncaster and Goole stations. Closure of the line is estimated to be costing Network Rail around £500,000 a week in fines.
However Network Rail has said that responsibility for the slip lies with the colliery’s owners and that they will be liable for the costs of the closure.