Complex sentence: Drainage problems in the mine meant that a proposal to build a low level sough was put forward in 1772 but this was not completed for many years, probably in the 1840s, being driven up from Hollowford Brook at Trickett Bridge in Castleton to the workings.
Split into simpler sentences: Drainage problems in the mine meant that a proposal to build a low-level sough was put forward in 1772 but this was not completed for many years, probably not until the 1840s. It was driven up from Hollowford Brook at Trickett Bridge in Castleton to the workings.