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Ultimate weapon for trench warfare

A Nottinghamshire contractor believes it has found a way to speed up motorway cable installations in the shape of a go-anywhere trencher from trench guru Roger Bourgein. Judith Cruickshank discovers the secret of the SlopeMaster

THE INFORMATION revolution scheduled to hit Britain's motorways has produced an interesting spinoff in the form of a specialist trenching machine, the result of an unusually close collaboration between customer and supplier.

The customer is Carnell Contractors, a specialist in the installation of motorway communications networks.

The supplier is LD Bourgein, which distributes the Case range of trenchers in the UK, plus its own range of equipment, developed from years of experience in the business.

Carnell was set up 10 years ago as a groundworks subcontractor. Managing director Darren Nelson has a general business background and came into construction through contacts in the industry.

Quick to seize the opportunities he saw, his first venture as an independent contractor came perhaps a little more quickly than he expected and he laughs as he remembers scrambling around to find enough manpower to carry out that first contract.

It was this business background that enabled Mr Nelson to spot the potential for a specialist in cable laying on the motorway network, and his hunch seems to have been born out. The company turned over £2.7 million in 2001 and is taking on ever larger projects.

By specialising in a particular type of work, and one that is relatively new, it became clear to Mr Nelson that a genuinely specialist piece of plant was needed to operate at maximum efficiency, something other than the mini excavators normally used. So he approached LD Bourgein as a company with long experience in all forms of trenching.

'What Carnell needed was pretty standard except for one variable, ' says Roger Bourgein. 'If you are working on a live motorway, then you are restricted to just 1.8 m of the hard shoulder. Exceed that by as much as a finger's width and a lane has to be coned off.' And that, explains Mr Nelson, 'means expensive night working'.

Trials had clearly demonstrated that Bourgein's Trench Wand attachment was the ideal excavating tool, but the tests had been carried out using a standard wheeled excavator - a machine far too large for Carnell's requirements.

A number of discussions followed, some attended by specialist attachment manufacturer David Kocurek.

It was at one of these meetings, after some hours spent wrestling with the problem, that Mr Kocurek suggested a trencher was the best option for taking the project on.

Mr Bourgein took as the basis of the new machine a Case 860 trencher. The first action was to strip out the four-cylinder Cummins engine and replace it with six cylinders. This immediately increased the engine power to 200 hp and upped the rate of hydraulic flow from 157 to 338 litres/min at 410 bar. 'We also fitted a big cooling fan, ' Mr Bourgein explains.

A backhoe boom fitted to the rear of the machine carried the Trench Wand, but the problem was then how to counterbalance the offset weight. The answer, says Mr Bourgein, was to think simply.

'We emptied out the right-hand side of the chassis and moved everything to the left. I then went to a local scrap heap and bought some sheet lead, which we had made up into specially shaped counterweights.'

Using this method Bourgein produced a stable machine with a powerful offset trenching head, and thus the SlopeMaster was created.

Narrow tyres completed the spec, ensuring that the machine could operate safely within the 1.8 m width of the hard shoulder.

And the range of the trenching arm allows the machine to operate in all locations, whether the line of trench to be dug is located alongside, above or below the hard shoulder, all without benching.

Another considerable bonus of the SlopeMaster is that the Trench Wand produces a tilth which is fine enough to be used for reinstatement. This immediately eliminates trucks bringing in reinstatement stone and hauling away unsuitable material, not to mention saving landfill and aggregate tax costs.

Carnell was delighted with the machine and first trials showed that productivity seemed likely to outstrip the best expectations. But then came a setback when the Trench Wand was stolen from the parked machine - an operation which must have taken considerable planning.

Despite advertising a substantial reward for the return of the equipment, nothing came back. Mr Nelson speculates that it was taken out of the country within a short time of being stolen. But it meant that until a new one could be manufactured and delivered, the SlopeMaster was out of action.

Happily, it was only a matter of a few weeks before the machine was back on the road - fitted with some additional highly sophisticated anti-theft technology.

Since then, the machine has been working constantly.

Currently it is carrying out a contract on the M5 and Mr Nelson reports that in good ground it is producing a consistent 500 m a day. This, he estimates, is around five times as much as would be possible with conventional mini excavator methods.

A long-term contract is currently under negotiation and Carnell is also looking towards the rail industry, where Mr Nelson can see plenty of opportunity for a machine with the output and versatility of the SlopeMaster.

The machine has aroused considerable interest among other trenching contractors, reports Mr Bourgein, but so far Carnell is alone in having the highoutput SlopeMaster in its fleet and is already some way towards winning a return on its significant investment.