If you put MRO-R18 over R245 and get it to line up properly, Muttrall Shaft corresponds to Muttrall West Shaft, which is sunk on the rather-stoped tin lode. There is a bit of a historic enigma which Ham Jenks was also unclear about....that Muttrall Lode was actually a tin lode. The later plans do not show the tin lode, but call the main telegraph hill copper lode "Muttrall Lode". I think this is wrong. Thomas, with his 1819 map and report, calls the main lode "Wheal Unity Lode" (which it is) and refers to the tin lode separately.
It is unclear whether the tin lode is parallel to the copper lode (this is referred to in text, but the R18 plan when overlaid, looks like the adit level in the Muttrall Section follows the outcrop of the tin lode and the copper lode was developed after. My latest think is that the footway shaft is an adit shaft, and Old and East Muttrall Shafts are on the outcrop of tin lode. I think Wheal Muttrall was a tin mine and later on, the further development of Gorland involved stripping out the copper on Wheal Unity lode....where I don't expect it was very rich.
There are a couple of anomalies indicated on the R18 plan and if the tin lode was an earlier thing (which would account for it's different mineralisation and dip) it's possibly displaced by "a load" of meters and then this would all make sense. If this isn't the case (and there are no other older structures which would show a similar displacement) it means there is a whole lot more unrecorded structures which would really complicate things.
I'm going to have a look at the very early Wheal Gorland cost book in CRO, to see if there is any other written information as to what was what. It's quite clear that Wheal Unity Lode (the minerally copper one) was quite a major show, but things indicate the muttrall shafts were first used for tin, on the tin lode. The copper being hit at depth, on the underlie.
Either way, the evidence for everything is severely limited and I'm sure at some point, more evidence will be obtained, one way or another.
One thing is certain, it is VERY interesting.
Another thing, from a minerals point of view is the difference between Robert's Lode (aka Great Gossan lode) which was the source of a lot of the tile ore and cuprite and the rest of it being earlier and of different composition.
Looking at the plans and seeing what cuts what, it appears that there was (perhaps) a tin mineralisation resulting in the tin lode, then the main NE-SW copper mineralisation and then perhaps a further series of movements resulting in "stuff" on the strike of Great Gossan, then everything being subjected to crosscourse movement later on.
It is a proper puzzle which requires a lot more evidence to get a handle on. It's quite likely that early mineral samples are caught up in the nomenclatural confusion so little can be inferred from their characteristics.
It would most certainly be interesting to see if there are any pillars left in the tin lode and whether these can give an indication of the nature of the lode.
I'd be interested in having a chat with anyone who is trying to make sense of the layout of the area.
The material in the west shaft tip doesn't seem to be very interesting. There are no sulphides present at all. The initial thought was that west shaft was to the west, footway was old shaft and that put "another shaft" where one was found and capped years ago. That would have put west shaft as a later addition, which miraculously appeared on the later plans.
Sadly, the records the old men left are either in private collections, or are rubbish. I don't know where the plans were copied from, but the later ones are MRO copies of something earlier and missing..