Case study Mortimer Quarry

The director of a quarry products company in need of a new tunnel for a quarry outside Reading, returned to Bison Precast’s design team to recreate an order he had made for a similar job some years previously.

Andrew Liddle, Divisional Director of Hills Quarry Products, ordered a 30-metre belt conveyor reclaim tunnel for Mortimer Quarry in Reading, composed of 16 three-metre by three-metre concrete box culverts, to match the reclaim tunnel he had installed at Stoney Wick quarry in 2010. The box culverts for the tunnel, which, once constructed, was buried under a pile of sand and gravel excavated at the quarry, had to be manufactured to withstand the considerable weight of material continuously falling on top of it.

Andrew Liddle said, “The design of reclaim tunnel I had constructed for our Cerney Wick quarry, outside Cirencester, was ideal for containing a conveyor belt system and has worked efficiently since its installation, so I decided to return to Bison Precast and effectively repeat the same order for a different quarry.”

The reclaim tunnel systems can process up to 1,200 tonnes of sand and gravel every day. In each tunnel, small openings were made at the top of the two middle box culverts to form a single opening when the two culverts were installed and enabling material to feed through from a cone above.

“The concrete box culvert system designed by Bison Precast lends itself to this type of reclaim tunnel,” continued Andrew, “as it’s essential to have minimum clearance either side of the conveyor belt. This system gives you more space and affords less waste, and I’d certainly recommend it to other quarry operators.”

Thomas Randell, Technical Sales Manager for Bison Precast said, “Our design team based this tunnel system on the previous job for Mr Liddell and Hills Quarry Products. It was created to support not only 8000mm of fill, but also withstand vehicle loadings. The box culverts were effectively identical on both projects, facilitating a swift design period and a faster turnaround for the customer.”