That's 'em! It's a few years since I last had a trudge around those parts! :~)
Thanks Tony. At least I won't tell a contractor his dolomite is rubbish, rather confirm that it has the right mix of sizes.
Just out of interest, what is DTp2 ? Is that the 50mm crusher run stuff?
Not quite. DTp2 has a slightly different 'grading envelope' to DTp1. I can't fiond the spec just at the mo', but if memory serves me well, it has more 'dust' than DTp1. It's a minoor diff, and not one that would make a masive difference to a residential drivewa\y, but, seeing as it's the same price (to withing pennies!) as DTp1, you might as well have the best stuff!
50mm crusher run is a very loose term that would probably be classed as a "Selected Fill Type 1 (SF1)". There's no grading envelope for 50mm C/run - it's all, more or less, passed through a 50mm sieve, so, theoretically, you can end up with all lumps or all fines, but, generally, it's a rough mix of lumps and fines.
Aren't you glad you asked! ;)