Nasty shale processing

[AS48 <as48@xxxxxxxxxxxxxxx>]

I have already sent the following enquiry to the micropal. net, so those 
of you who have already seen it, please forgive me for foisting it on 
you again.  


As most of you know, one of the major bugbears of fossil (and 
particularly microfossil) preparation is breaking down hard indurated 
and/or black shales to extract the enclosed beasts. In my time I've had 
a go at most methods, without great success. I've just now been 
presented with some hard grey graptolitic shale from the Welsh 
borderlands. I've been asked if I can break it down to free the 
graptolites. This stuff is immune to treatment with the usual chemicals 
like Hydrogen peroxide, Petroleum ether and apparently all acids except 
HF. I could in fact use HF and am aware that some methods have been 
published, but I would like to avoid HF if possible.
   I was wondering whether out there in Palaeoland, anyone has come 
across anything new that could chemically disaggregate this type of rock 
without risk to life and limb.

Best Wishes to all,

Andrew Swift
Dept of Geology,
University of Leicester,
UK