The mines at the bottom of flagdale are very interesting, i saw them last summer, i definately remember seeing something about them somewhere, perhaps it was on this forum after i had been and seen them.
Certainly when looking at the DCA information on the caving areas wormhill does look like a promising area, with 10million gallons a day of flow.
http://thedca.org.uk/access-information/caving-areas
Jim lister of the TSG has definately tried to get permission to dig wormhill springs, but i believe he was turned down.
Staying at the same valley bottom level as wormhill springs the next nearest (possible) outlet for water would be at the quarry near the millers dale car park, although i've been to wormhill about 4times i've not parked at this car park, but you can drive down from wormhill towards millers dales and you will find the car park at the bottom.
This quarry will be looked at some point in the near future.
Working up the valley i guess the next feature you will find is the mine workings in flag dale. I'm still yet to don caving gear and have a look at these.
My last visit to wormhill was after some of the snow this winter, but unfortunately there was very little to see in terms of blow holes. However i had a good look at flag dale above the mine workings. however i could not see anything there either, although at the end of flag dale there is a very interesting shakehole, although it is just inside the nature reserve that runs from the mine workings to the fields at the top of flagdale. This makes permission for digging this rather problematic.
Again working up the valley, there is a path which effectively splits north and south wormhill, this path runs from the telephone box south of tunstead to old hall farm in wormhill.
http://binged.it/1xqHIfl
This is a good spot to view some of the complications of hydrology in wormhill.
In several places a band of lava runs through the landscape (i'm unsure as to how deep this lava runs), essentially this lava forces some of the water up from below and creates a stream on the surface. This has been harnessed by the farmers by creating round concrete troughs for watering holes, one upstream and one downstream.
Much of wormhill is dominated by such modification by farmers, which would suggest that there is a lot of bedding plane development at this higher level, maybe caused by the bed of lava running through it. Including the "well" in the centre of wormhill to commemorate brindley, one of the founding fathers of the uk's canal system
http://en.m.wikipedia.org/wiki/James_Brindley
All is not lost however for lower level cave development in wormhill. Firstly, please search for the work on hydrology done by john gunn on behalf of lafarge tarmac for development of their tunstead site.
Although i do not fully understand a lot of the work done by john, some of the conclusions are easy to lift and apply, there are some holes north of the quarry that flow out at wormhill springs without coming out in tunstead quarry.
There are a few tantalising depressions in the land, particularly about halfway between tunstead telephone box and old hall farm on the northern side, there is a rather large depression in the land. This would suggest that if there were cave below there could be a massive boulder choke below this depression.
North of this spot are a number of old mines, as i have no idea what these mines are, i cannot do any research into whether they may lead into natural. Most of these mines are just south of the road from bole hill to hargate hall. I will need to do some searching into these mines.