The earliest dated reference to Bournmoor Colliery is in February 1784 when the 'scale of changes for wagon maintenance at General Lambton's Collieries at Harraton, Lambton and Bourn Moor' were recorded. This suggests that the initial sinkings for the colliery may have begun in 1783 or earlier. In August 1784 calculations regarding the dimensions and accounts of an engine house at Bourn Moor were made by George Green. The engine house had provision for three 13 foot diameter haystack boilers and an undated plan showing the same dimensions and the title 'Bourn Moor Engine House' has survived. The A pit lay to the north side of Bournmoor Farm. B Pit (HER 4997) at NZ 3207 5154. It is not clear which of the early pits the engine house was designed for. The colliery was expanded in 1789-1797 with the sinking of C Pit which lay to the north of the A183, probably sunk in 1789 or 1790. In june 1791 D Pit was working the high Main Seam suggesting that the sinking may have begun as early as 1789. Although General Lambton would have been involved in the establishment of Bournmoor Colliery (other Lambton family collieries were Lumley, Harraton and Lambton) it is likely that from the beginning the operation would have been leased out. An abstract for an agreement has survived dated 1st January 1785 by Mr Featherstonehaugh and Co for working General Lambton's Collieries at Harraton, Lambton, Bournmoor and Lumley for five years. In 1800 John Buddle was appointed inspector of the Lambton Collieries and reports soon followed regarding Bournmoor Colliery. The upcast was then being aired from Lady Ann Pit (HER 3141). Buddle descended the D Pit shaft to the Maudlin Seam and noted the poor state of the roof which required two rows of props. In 1800 a new set of pumps were installed in the D Pit engine house and a new beam installed in the following year. An estate map of 1812 shows a raff (timber) yard, brick garth, cottages (D Pit Row), engine and small gardens. Records are illusive at this time which suggests that the mine was used for pumping rather than drawing coal. The importance of the pumping role is underlined by concern at the state of the engine, with the option of its abandonment in favour of the Morton engine (HER 3140) being actively considered in 1814. A significant change occurred in the organisation of the Lambton collieries in 1813 when John Lambton came of age. He immediately took back control of his collieries from the contractors and in their place he appointed a 'colliery board'. In 1815 deposits of salt were discovered coating the inner surface of one of the boilers at D Pit. Similar discoveries at Lambton led to the discovery of a saline spring and the subsequent establishment of a salt works at nearby New Lambton. D Pit was closed by 1823 and the engine is likely to have been used exclusively for pumping. It is recorded as drawing water from a dormant colliery in 1835. The centre of coal production on the Lambton Estate at this time appears to have shifted from this area to collieries at Cocken, Sherburn and Littletown. Around 1854 a new pit was superimposed on the D Pit and coal production was resumed. The old arrangement of the D Pit was replaced by new buildings, including a new engine house erected on the south side of the shaft. A group of at least 19 buildings had been built to the north of the d Pit, arranged in a rectangle so enclosing a central yard. These are likely to be houses with a series of gardens on the south and east sides. By 1856 the Lambton Railway (opened in 1819) had been extended with the addition of the Lambton Railway D Pit Branch linking the D Pit and Lady Ann Pit to the Lumley Branch. The Bournmoor engine was located at the junction of the D Pit and Lumley branch lines. This may have been a stationary steam engine and a long narrow building to the west, recorded on the Ordnance Survey 1st edition map as 'Duney's Bay' may have been an engine shed. An early electric telegraph line (HER 3144) was c