'The Seaton Delaval collieries had begun in 1838 with the sinking of what was to be known as A shaft. Eight shafts were finally sunk at the location. The shafts were in pairs, ten feet apart and eight feet in diameter. Each shaft was sunk to different coal seams at different depths. The multiple headgear within such a small area must have made for an impressive, and busy, sight. In fact, the only other colliery with multiple headgear was at Bedlington A pit. Some of the buildings from this complex still remain as part of the Seaton Delaval Industrial Estate.

In 1929 Seaton Delaval Coal Company merged with Cramlington Coal Company to form Hartley Mains Collieries Ltd. A period of modernisation took place after this merger, with electricity and mechanical coal cutters being introduced to the collieries.

Again, in March 1943 Hartley Mains Collieries Ltd was merged to become part of the Bedlington Mains Collieries Ltd. Nationalisation in 1947 brought about some further modernisation of the collieries. But by 1956 the colliery was showing its age and was put onto single-shift working. Seaton Delaval Colliery closed in 1960.

Away from the main Seaton Delaval Colliery site, however, in 1859 the company had extended their wagonway to reach a new sinking in the Newsham ward of Blyth. This was the Forster Pit. The first shaft was sunk to a depth of 737ft at a diameter of fifteen-and-a-half feet to the Plessey seam. However, due to geological faults this was found to be unworkable so an inset was made at 668ft to the Low Main Seam.

The colliery was so productive that by 1870 a third shaft had been sunk. A community grew up around the colliery which was called New Delaval. A brickworks was built on the colliery site to supply the materials for the miners' housing and other colliery buildings.

Geological faults in this area continued to be a problem to the colliery owners. There are two major faults between New Delaval and Seaton Delaval which isolated a large tract of coal. It was judged, by the Seaton Delaval Coal Company, to be less expensive to sink a further shaft than to drive a roadway through the faults. This they did in 1884. This is the triangular feature adjacent to the wagonway. It was known as the Relief Pit. A surface tub line haulage system was laid from the facilities at New Delaval Forster Pit to Relief Pit, powered by an endless rope hauler. This also worked the underground haulage system.

By 1900 the New Delaval collieries were producing well and were modernised with new headgear and tipplers. These good fortunes were not to continue and in 1930 the pits were made idle with only maintenance work being carried out. The headgear was moved to Dudley Colliery and miners evicted from their homes, which was considered as a cynical ploy to get the men to move to other pits in the group. However, the New Delaval pits were given a reprieve in 1933. According to an article that appeared in the News Post Leader in 1951 the Gloria pit was sunk in 1935 to allow access to coal hidden by a horseshoe-shaped geological fault. All the New Delaval pits were finally closed by 1955.

An article in the "Our Colliery Villages" series appeared in the Newcastle Chronicle during 1873 which described New Delaval. This is a short excerpt:

"New Delaval is not far from Newsham, but the colliery belongs to another company. Two shafts have been sunk near each other, one of which is entirely devoted to the working of the yard seam, while the other descends to a lower deep still, and is used for working the lower seams. The engine houses are of the most massive description, and the pit gearing, like that of Barrington, is light and elegant, being made of iron. About 350 or 360 are employed here, but as there are only about 200 cottages built as yet, large numbers of men and boys reside at Old Delaval, which is some three or four miles away. A train of carriages, however, is run between the two places several times during the day, at such hours as may be convenient for the men going to or returning from work."

From this we can establish that the Relief and Gloria pits made a comparatively small footprint on the ground as the coal produced was being processed at the larger collieries in the group. The workforce was residing in the well-established housing at the main colliery sites, which was close enough to actually walk to work, but special trains were provided along the colliery's own wagonway.'

Alan Fryer, Seaton Delaval Collieries, Burradon History, accessed 22/06/20, https://www.burradonhistory.co.uk/2013/12/seaton-delaval-collieries.html