Case Study

Open Cast Mine Regeneration Mirfield, West Yorkshire

Second phase of the creation of an industrial park

Moorhead Excavations/Caddick Construction
Lime/Cement Treatment
20 weeks



The second phase of an industrial project at Mirfield near Huddersfield in West Yorkshire. Working closely with Moorhead Excavations on the earthworks the regeneration of this open cast coal mining pit site will deliver five industrial units. We also worked with the same team to deliver the first phase in 2018. The site was not without its challenges as the site fell some six metres across part of it and the works were carried out over winter - less than ideal!
Our works included the construction of a Structural Fill platform with a maximum depth of around 6m where the open cast pit had been mined out. The slope of the pit wall was also 1 in 2 requiring careful placement of treated layers. The rest of the site was more level but still required treatment. The specification required CBR of greater than 15% and 95% compaction with less than 5% air voids requiring lime/cement stabilisation across the site.
Two units also needed supplemental support with CMC (Controlled Modulus Column) piles to avoid differential settlement due to the proximity of the pit wall. To enable this we constructed a 5500m2 piling platform to accommodate the piling rig loading. The platform then performed the role of a load transfer slab and structural fill was then laid in layers over the top up to finished level.
The structural fill comprised 30,000m3 of lime and cement stabilised upfill built up in layers using site stockpiled materials. Finally the 38,000m2 of external yard and access infrastructure was surface stabilised to achieve 30% CBR.
Two mixers were utilised to mitigate lost programme time due to particularly inclement weather (frost and rain) across the Pennines - although this is difficult to believe looking at two of the images!