It was May 2010 when David Hunter of Torwood announced in the comments section that he had found an identical pool at Carbrook. David and his wife Stephanie had been researching Carbrook House. As they walked the grounds, they spotted a ring in the grass that had been missed by locals who had lived all their lives in the area.
They started scraping and soon uncovered the circular shaft with a wall of three bricks thick but it was full of earth — so no way of knowing if there was a Brick Arch. There was a nearby manhole, also full of earth.
The internal diameter of the shaft is a rather quirky 19 feet 7 inches whereas the Torwood Blue Water Pool is a perfect 20 feet.
This shaft was right above the entrance to the (north) Carbrook Clay Drift Mine. Jones Saw Mill once occupied the Carbrook grounds but now only a few concrete machine plinths remain. A local man who has lived much of his life in the area had a story that the shaft was a creosote tank for soaking timber.
The nearby manhole, was saturated with a tarry residue that had similarities to creosote.
It was time to separate the facts from the red herrings and Stephanie started to think it might be a Gasometer for storing coal-gas. This might account for the tar residue in the manhole.
About a mile to the east is Glenbervie House and we know that in 1850 it had its own Gas Plant to, presumably, fuel the new gas lighting. Carbrook could quite reasonably have had its own Gas Plant.
Stephanie found the following drawing of a coal gas manufacturing plant from 1911 and reckoned the shaft may have been filled with water. A bell shaped lid would rise and fall as the gas flowed in the goesinty and out the goesooty.
Then came the proof. A 1910 Ordnance Survey map showed not one but two Gasometers. Well done the Hunters — investigation closed — after they find that second shaft! The Gasometers were built long before the Carbrook Drift Mine — strike one red herring.
Perhaps understandably, Stephanie is not a great fan of my Airshaft theory for the Torwood Blue Water Pool and she suggests a possible Gas Plant for a nearby large House. The nearest house is Denovan but it is 1 kilometre away. Carbrook is 132 metres and Glenbervie is 248 metres from respective gas plants — both are next to their stables.
The strongest argument for the Airshaft is simply that the Brick Arch points towards Quarter Colliery number One Shaft.
The snag is that it is fully 1.6 kilometres from the production shaft. The later shaft, Quarter number Two Shaft has its own Airshaft just a few steps away.
Was Torwood chosen for its height to produce a good natural draft before they had electric fans? — there is at least one wee snag.
The Dales Wood stands just North East of number One Shaft and is 10 metres higher than the Blue Water Pool ground level. Dales Wood would seem to be a more sensible location for a natural draft Airshaft.
Hopefully there are more clues and facts to be discovered. My next job is a photo up the Brick Arch.