Speculation Mine would have been in the area of the Mireystock / Serridge cross roads at the very "top" of Upper Lydbrook........ south along the road towards the Bike Hire centre - Peddle-a-bike-away ?

http://www.lightmoor.co.uk/forestcoal/EastDean.html

Cannop maybe but stretching it to call Speculation Mine in Lydbrook.

However nice to see the mine's name living on.

Owner Baldwin Bros., Yew Tree Villas, Broadwell, Lane End, Coleford
Name Speculation No.2 Drift
Location Upper Lydbrook

http://www.lightmoor.co.uk/forestcoal/CoalSpeculation.html
On 28 June 1944 the gale was re-granted as Speculation No.2 to an E. Baldwin.

Speculation Colliery to Lydbrook Station
Speculation car park is signposted off the B4234
south of the junction with the A4136. Between the car park and the road, at SO 61271363, a
path on the line of the tramroad runs north and south. Going north, at SO 61231397 the path
turns east but continuing north through undergrowth, traces of a trackbed can be seen where it
enters a ravine. Here was the Mirystock tramroad tunnel, 200 yards long; in 1865 it was in
danger of collapse and was opened out into a cutting. Continuing, the ravine is soon partly
blocked by spoil; one scrambles up and continues on the line which converges with the
railtrack at a shallow angle, merging at SO 61341425 approximately. On the west side is a
drystone, backward sloping retaining wall which looks like tramroad, rather than railway,
work. This section is probably only negotiable in winter or spring.