Tunnel vision at Holme Hall

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New 60m long tunnel to open up new extraction area at Tarmac’s magnesium limestone quarry near Maltby

WORK is currently well under way on a 60m long tunnel that will open up a new production area at Tarmac’s Holme Hall magnesium limestone quarry, near Maltby, in Yorkshire.

Located beneath the busy B6094, when completed later this year the tunnel will be large enough for a 4m high Caterpillar 775 dumptruck to pass through.

Work on the tunnel commenced in February 2011 and had to be carefully designed so as not to disturb a 15in cast iron high-pressure water pipe that takes water from a borehole at Austerfield to Clifton Reservoir, which is used to supply Rotherham.

‘Construction of the tunnel has been very complex job because of the water pipe,’ said Luke Brooks, Holme Hall and northern district concrete zone manager at Tarmac. ‘We are very pleased at the progress we have made to ensure that disruption is at a minimum for the local community.’

Contractors Morgan Sindall are undertaking the horseshoe-shaped tunnelling work using an innovative hydraulic hammer and patented concrete spraying construction technique that removes the need for rock bolts and drilling, thereby minimizing disturbance to the water pipe.

It is envisaged that the first dumptruck will be able to drive through the new tunnel by October 2011.

Tarmac, who employ more than 70 people at Holme Hall Quarry, expect to extract approximately 34 million tonnes of limestone at the 200ha site over the next 20 years.