A line of Bell Pits running across Newcastle's Town Moor, I had heard that they were visible, but never seen them before. 4 are listed on the HER with GRs supplied, but even with these and a low November sun, I could only find 2. Looking at the Lidar there seem to be at least 10 or 12. They are listed as being post medieval on the HER and were not mapped on the first Ordnance survey in the 1850s so would have disappeared by then. Likely mining the High Main Coal.
From British History Online
The Town Moor, or Castle Moor, was originally, according to Bourne, a wood very famous for oaks, out of which were built many hundred ships, and all the houses of the old town of Newcastle. It was given to the burgesses, he says, by Adam of Jesmond, about the reign of Henry III. But, by a clause in the charter granted to the burgesses by Edward III. in 1357, this Moor appears to have been an appurtenance of the town, under a certain fee-farm rent, paid to the crown from time imme morial. This king granted the further privilege of digging coals, stones, mines, minerals, &c. therein, for the use and benefit of the burgesses. (fn. 1)
A colliery that was working on the Town Moor at the time of the Commonwealth, extended 100 acres under the superficies, and was valued to the town at £35 per annum. The colliery on this Moor was advertised to be let April 16, 1763."