Coal Authority Works to begin on former Thornley Colliery site
The Coal Authority is expected to begin works on 13th January, to install a bore hole to monitor mine water levels, on the Woodland Trust land along the Hilly Path. The woodland may be known as Jubilee Wood or Coal Hill Wood.
The Authority has provided the information below for residents.
Work will continue for approximately 7 weeks. Once the drilling has finished, the site will be left secured with an access chamber cover. We will use this to access the borehole to monitor the water levels.
Thornley Colliery was sunk in the early 1830s, with first coal extraction in 1834. Below surface, coal was extracted from five seams; Five Quarter, Main Coal, Low Main, Hutton and Harvey. Following three decades of mining, Thornley Colliery was closed in 1970, the washeries in 1972 and the pit heaps were reclaimed in 1974.
During mining, water entered the workings via the surrounding geology and began to fill the workings when they were closed. Due to this, we manage the water within the mine workings to prevent it from interacting with the drinking water aquifers (underground reservoirs).
Often when the collieries were closed, the mine shafts were infilled, preventing access to the mine workings. To obtain data about the status of flooding and chemistry of the water, the Coal Authority often need to sink boreholes from the surface down to the mine workings.
At Thornley, we are sinking a borehole through about 157m (515 feet) of rock to the mine workings in the Five Quarter Seam. The Coal Authority will use this borehole for routine monitoring to confirm the mine water level at Thornley, and how this corresponds to other monitoring sites in the mine water block.
The data will be used to confirm mine water management strategies for the area and to understand how they could be improved in the future.
We don’t expect the work to cause any disruption. The contractor will put in place measures to ensure public safety, and there will be signage on site displaying further information. The Coal Authority thanks residents for their cooperation.
If you have any questions about this work, you can contact the Mining Remediation Authority on customerservice@miningremediation.gov.uk, or contact the Parish Council and we will do our best to assist.
