Brodsworth Mine Water Monitoring Borehole

The Coal Authority (Client) was established by Parliament to undertake specific statutory duties, set out in the Coal Industry Act 1994, associated with licensing coal mining operations; managing property and the historic legacy arising from the ownership of the coal reserves and underground workings; settling subsidence damage claims not falling on coal mine operators and providing access to coal mining information.

1. Background The mine water in the Barnsley-Manvers-Grimethorpe mine water block is thought to be rising. Recovered mine water in this area represents a potential risk to the overlying Permian aquifer, as well as surface water in the area. To assess the mine water regime, and inform future mine water management strategies, a borehole is required that would target the Brodsworth or Bullcroft colliery mine workings. Therefore, the Coal Authority (CA) requires a mine water monitoring borehole to increase the monitoring infrastructure in the area. The data from this borehole will be used to improve understanding of mine water in the Barnsley-Manvers-Grimethorpe mine water block, through water level monitoring and quality sampling.

2. Key Requirements Operational time: By summer 2025

Methodology: Anticipated to require a pilot hole to be drilled by wireline coring methods to assist in maintaining verticality

Borehole depth: Estimated 515 metres below ground level (m bgl) Final internal diameter Minimum of 150mm

Borehole deviation: <2m from surface location of borehole (<0.2 from vertical)

Design life: Minimum of 20 years

Headworks: To be completed under a square split lockable manhole cover at surface, minimum of 600mm x 600mm with D400 rating

3. Delivery The CA look to collaboratively engage with landowners to obtain access and a licence to carry out the drilling works. It should be noted that this engagement may take up to a maximum of 15 months, from initial point of contact however, in some cases this is significantly less. With this in mind, the Invitation to Tender is sent out part-way through this timeframe. Nevertheless, and to avoid any delays, the Contract will be awarded with a Contract Award Date and Start Date as two different dates.

4. Engagement Opportunities The CA are always looking for ways to improve and streamline projects. Due to the defined verticality requirements, it is envisaged that the most robust and reliable method of completing the mine water monitoring boreholes is by drilling a pilot hole using a wireline coring system, followed by reaming to the required diameter(s). However, the CA would welcome your feedback on this including any other methods that may be deemed more suitable to guaranteeing verticality such as directional drilling.

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