No, nobody has mentioned that one yet :)
For the benefit of anybody coming late into this post, it's all about what is worth, and what is not worth, including on mineral/product type drop-down. This appears both when adding mines and when searching mines, and also runs the mines by type pages
http://www.aditnow.co.uk/mineral/mines-quarries-uk-mineral-type.aspx .
I add to it fairly frequently, and after feedback from other members.
Basically we add major minerals and products and take a point of view on others. For example Fullers Earth was decided to come under Clay, and certain very specialised minerals where only 1 or 2 mines in the UK exist we opted to list under 'Other Rock', but in nearly every other instance add a specific classification.
I update the list every month or so, aside from anything else it avoids lots of 'unknown' mines which isn't very helpful to people looking for information.
my orders are to sit here and watch the world go by