Interesting, in GrahamI's photo of 3/4 of the mill built, it seems a small section of the third quarter is a smithy or workshop- opposite the water wheel. It has a large slate chimney and a couple of smaller iron ones, suggesting a forge, and it would pre date the seperate workshop buildings.
Of course it could also be a steam engine driving the mill, with the exhaust up the two smaller chimneys and the boiler towards the rear... but I don't know.
The "mark 1" connection was in existence by 1865, and was superceded by the "mark 2" between 1877 and 1889.
The Votty Tuxford Incline was working to DIffwys Floor 3 (it's final location) by 1912, allowing Votty to tip over their old tips, followed by Maenofferen at a higher level.
The workshops appear to have been built between 1924 and 1926, the main electrical building around 1909.
The "new" connection to the Rhiwbach tramway was made in 1930, using the reversing stub in the oild quarry.
Grahami
The map is the territory - especially in chain scale.