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Tue May 18 2021

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New demolition technique proves its viability at Croft Quarry

19 Oct 20 Demolition specialist AR Demolition has brought down structures at a Leicestershire quarry using methods not usually seen outside of military applications.

The Croft Quarry screen house coming down
The Croft Quarry screen house coming down

AR Demolition used weapons-grade hypersonic ‘kick and cut’ charges to bring down a large screen house at Croft Quarry.

Chief executive Richard Dolman believes that the project is the first time such charges have been used in the demolition industry, without the normal pre-weakening activity usually employed to bring a structure down. He reckons that the technique could now revolutionise safety in the industry.

AR Demolition, which is based in Carlton near Market Bosworth, has been working at Croft Quarry since the start of the year after being contracted to complete decommissioning demolition by site owner Aggregate Industries.

The explosives work was part of a joint project to demolish the 1,200-tonne screen house as well as 150 metres of conveyor belts at the bottom of the quarry pit.

Designed by explosives specialist Alford Technologies, the kick and cut technique brings together two forms of explosive charge. The first charge effectively carries out the task of pre-weakening that would otherwise be done by human crews inside the structure.

Since the collapse of the boiler house during demolition at Didcot power station, killing four demolition workers, clients have sought to avoid specifying demolition methods involving pre-weakening. The boiler house came down unexpectedly during pre-weakening operations ahead of a planned controlled explosion. This is the context in which Alford Technologies has been developing the kick and cut method.

Mr Dolman said: “No one has used this technology in UK demolition before. It was a project which has taken considerable forethought and planning and we are delighted with the results. It’s a major stepping stone for us and, in my view, a huge moment for our industry. The fact that you can bring down buildings by severing steel without pre-weakening is a landmark moment.”

He added: “Alford Technologies have been working on these theories for a long time but, until now, there has been typical reticence in our industry to adopt new technologies. So I’m pleased to have been able to put the ideas into practice and find new ways of increasing safety in our sector.

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“It was our first opportunity to test the technology and we have learned lessons along the way. We’re now looking forward to using the method on future projects.”

AR Demolition chief executive Richard Dolman
AR Demolition chief executive Richard Dolman

Alford Technologies managing director Roland Alford, son of the company’s founder and chairman Dr Sidney Alford, said: “We used our Dioplex charges to make a hypersonic blade which cuts through steel like butter, eliminating the need to burn and weaken steel beams.

“When combined with the Wallhammer kicking charge to remove the columns, the speed of these military grade munitions means they are relatively easy to control.

“Without the need to use human beings on weakening work, safety is greatly increased. If necessary, the charges can be placed by robots thereby removing the human element completely.”

He added: “We are proud to have worked alongside such an innovative contractor to have brought this technology into practical, commercial usage. And we look forward to working with AR Demolition on future projects.

“The demolition industry now stands to benefit from the evolution of scientific improvements which, combined with the vision of a man such as Richard Dolman, mean that we can shape the future of the industry and improve safety for everyone involved.”

Conveyor belt explosion
Conveyor belt explosion

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