It turns out that the walkers did have boring and testing works in conisborough,so there might be remnants on the ground.
In particular cannons balls buried in the ground from test firings.
Fresh piece of informations on the boring mill at conisborough used by the walkers.
Some industries had been and gone by the middle of the 19th century, one notable example was the Burcroft Boring Mill.  Built in 1779 by Samuel Walker, an Ironmaster from Rotherham.  The mill was used in the boring and test firing of cannons cast at  masborugh in Rotherham; many of the cannon on Nelson’s Flagship “HMS Victory” were bored and fired for the first time at Burcroft.  At sometime before the mid 19th century the boring mill was converted to a sawmill, among the items made at the mill were bobbins for use in the Lancashire cotton mills.