I have had an issue with players getting the instant mine ability.

I tracked the error down, and deleted my preciousstones config, it generated a new one and the issue was gone.

So, I modded it again and it worked well, but then suddenly it started again.

Have I missed something in the config that might cause this?

I am on CB1.1 R4 using version 8.2.8

http://pastebin.com/SCLg6nnY

I see you're not using the field "mine-delay-seconds" -- Is that on purpose?

Example:
mine-delay-seconds: 3

The only other thing I can think of is that players are somehow being promoted to a permission group that has
the field "required-permission: preciousstones.mine"
(Set in whatever permission plugin you use.)

I'[ve seen no reference to that until you mentioned it.

And the perciousstones.mine is the proximity mine...giant explosion.

I am suffering from instant break.

You are giving them the " preciousstones.admin.superduperpickaxe" permission and they are typing ///