Way back in the 40's, a gang of us from Pitsmoor would catch a tram to Middlewood terminus then walk to Oughtibridge and Wharncliffe Crags. We would walk by way of, I think was called, Oughtibridge Lane. Nearly at the top of the hill was a path to the left which ran along the crags. This eventually ended at a large house where you could get refreshments.
Alongside this path at intervals of 50yds or so, were three or four large pits full of water and sometimes if it was summer and warm enough, and we had the 'bottle' we would dive in for a swim.
The pits were variable in size, but perhaps 10 to 15 feet square and about 10 feet deep, full of large stones and iron, and if I remember right, the water was clear but with a greeny blue color to the detritus in the bottom. Any amateur industrial archaeologists know what they were?

There used to be gannister mines along the hillside beneath Wharncliffe Crags, these pits might have been what remained of them.

I seem to remember Gannister was used in manufacturing steel, right? What kind of excavations would they have been, shafts or a sort of drift? Thanks for the feedback Greybeard.

Hi Texas, - Gannister is a hard shale type rock high in silica content. technically it is a clay used as a refractory material but it is so hard that it first has to be ground into a powder and mixed with water before it can be formed into firebricks. It was heavily used in the steel industry for lining furnaces etc.

Extraction was usually via drift mines into the hillside and there were many of them in the Wadsley, Worral and Oughtibridge area and some around Bradfield.

There is a large permanent pond in a field close to where we live which I found out was the old entrance to a gannister mine.

Interesting book on the subject from here...

http://hometown.aol.co.uk/__121b_B25IfaTchhC/Tp6s/zwBB6maKhfLZkAyjQF0rOX1nVI=

Presumably Greybeard, the quarry that was situated at the bottom of Rutland Road, produced Gannister. There was a brickyard nearby if I remember. The rock excavated there matched your description very closely, and material that could be found on Parkwood resembled it too.

Could be Texas, though the book only deals with the mines and quarries in this small area. Gannister it seems was only found immediately beneath the seam of 'Halifax' coal that runs through the area.

The Wharncliffe ganister pit kicked off in 1901 and was abandoned in 1909.
It had a relatively short life but they were many in the north of Sheffield including Worral, Wadsley and Outabridge