Cannel coal had been dug from bell pits on Bradshaigh's estate since the 14th century where the seam was very close to the surface near the Old School Cottages.
[1] The sough was driven to drain the pits, which produced both coal and cannel and extended the life of their shallow workings, which were prone to flooding.
[2][3] Bradshaigh recorded a detailed survey of the construction of the sough and its shafts with instructions for maintenance so that, "the benefit of my 16 years labour, charge and patience (which it pleased God to crown with success for me and my posterity) may not be lost by neglect.
[8] Between its outlet and Park Pit the sough passed through several layers of hard sandstones, mudstones and the Cannel and King Coal seams.
[7] Such was the importance of the sough that in 1687, the estate bailiff, Thomas Winstanley, ordered its inspection and cleaning from bottom to top at least every two months and "the least decay thereof in any place speedily and substantially repaired".
It was inspected 14 times between 1759 and 1767 and in 1768 workmen spent 49 weeks cleaning the sough and a payment was made for repairing the hoppets (buckets) used to haul debris up the nearest shaft.
[14] The sough discharged iron-rich minewater into the Yellow Brook in Bottling Wood, discolouring it, and the River Douglas downstream, with ochre deposits.