I'm attaching a map which might be of some interest. It's taken from the 1834 enclosures maps and I have overlayed the information from the relevant bits of Holme and Cartworth townships to create a composite covering the main quarry areas.
As you probably know, the township boundaries around magnum are a mess, with a bit of Holme wrapping round a bit of Wooldale and a detached bit of Cartworth. You need to see the Wooldale map too to get the full picture, but most of the areas relevant to the quarries are covered here.
You also need to look at it in conjunction with the the 1852 OS map, which I have an extract for this area, but suspect I may not be able to post it because of copyright.
The main quarries from 1852 tie up as follows:
Ellentree - parcels 110, 111, and part of 109 (H Lumb)
Ne Plus Ultra quarry (!) and Magnum Bonum - parcels 112 (J Firth), 113, 114
Round End quarry (Bare Bones) - parcel 117
Goose Hole quarry - parcels 232, 233
(One which I can't make out the name, north of Bare Bones Road) - parcel 214 (Joshua Littlewood & Benj Beeley)
Speedwell quarry and Non Pareil - part of 118 (John Harpin), 120 (W Bates) & 131 (S Morehouse)
I'm guessing that many of the quarries may have started up at around the time of the Enclosures Maps, or shortly after?
The other bit of info I have is from an account of a Home Valley Civic Society talk by Gordon Hallas (weekend Examiner 4th June 2011):
"Magnum Bonum Quarry had more than 60 people working in it in 1861, producing stone for local buildings and flagstones for railway platforms. The workers at Magnum Bonum Quarry lived in a group of cottages built for them in the hamlet of Magnum above Hade Edge."
And in relation to my 2x ggf John Turner, born 1821 in Elland:
(My own notes): Moved from Elland as a young man some time before 1840, to work at Magnum Bonum Quarries, Harden Moss, where he met and married Emma Mitchell, whose family had also moved from the Halifax/Northowram area to work at Magnum. He started out as a labourer ("stone getter" or "delver") through to 1854 (Matilda's baptism) but appears to have improved his lot as by 1861 he was described as a "stone merchant and grocer"; by 1871 he was a "quarry owner and stone merchant". At his death in 1889 he left a personal estate of £1,969.
As I live in a distant part of Lancashire, it's difficult to get access to West Yorkshire archives, so I'd be really interested if anyone can point me to any documents that might shed more light on the operation and ownershhip of the quarries.