Yes Simon, these professionals and other self proclaimed "miining historians" and "mining experts" often get it wrong.
The link you mentioned is typical - apart from the obvious error in believing it to have been a pumping engine house (the pumps were in two houses north and west of the shaft and still discernible as such in the 70s) the story is incomplete. Lifting only a passage from the description of the 1729 sinking they give the depth at 456 feet, which is repeated, by others, on "Information" :lol: boards at the cliff top and in Haig yard. If they had done proper research they should quite easily have been able to gather that the engine house was constructed, as you say, around 1820 when the shaft was deepened to work the Six Quarters. At that time winding by horse gin from the Main Band (at 456 ft) was superceded by the engine (installed 1822?), the shaft being 838 ft deep to the water lodge drift. It should also be mentioned that the shaft was 10 x 8 ft elliptical in the initial sinking but was 10 ft dia. in the deepened section.