Installation of three up to 120m deep diaphragm wall shafts with diameters between 8m and 35m at Woodsmith Mine in North Yorkshire (England)-PPT Presentation

PPT Presentation

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The Woodsmith Mine project in North Yorkshire, England, involves constructing three diaphragm-wall shafts up to 120 m deep and 8–35 m in diameter. The mine will access polyhalite, a naturally occurring, multi-nutrient mineral used as an agricultural fertilizer. The shaft solution was designed to avoid long-term impacts on the surrounding National Park landscape.<br /><br />Ground conditions comprise alternating sandstone and mudstone, with unconfined compressive strengths ranging from 0.5 to 115 MPa, as well as groundwater. Design work addressed complex geometry, over-consolidated rock-like ground, temperature effects and water pressure.<br /><br />The shafts were built using double-phase diaphragm walls excavated with a cutter. A hybrid cutter wheel, fitted with chisels, teeth and reamer plates, was suited to both overburden and hard rock. Construction controls included cutter inclination monitoring to meet a tolerance of approximately 1 in 600, GRP spacers to centralize reinforcement cages, and fast-swelling polymer to reduce slurry losses. Bentonite slurry was mixed, stored and de-sanded on site.<br /><br />BAUER’s B-Tronic system monitored cutter depth, inclination, rotation, pressure, penetration rate and other operating parameters in real time, supporting construction control and equipment servicing. The project reported 200,000 man-hours without a RIDDOR-reportable incident.

Keywords

Woodsmith Mine

North Yorkshire

diaphragm wall shafts

polyhalite

agricultural fertilizer

groundwater

hybrid cutter wheel

bentonite slurry

B-Tronic system

construction safety