coaldust on compost heaps

hello all this is my first post. I have been growing veg on and of for a few years now but have just got my first allotment this year after a 2 year wait I was wondering if i could put the ashes from my coal fire which also burns wood, onto my compost heap, i once heard that coal ash is not good for the veg plot, i would be gratefull for any info

thanks

Wood ash good.
Coal ash not good.

Edit: Previous post made whilst I was slowly making mine.
         Glad to see that we agree. 

here...here...here...

Sorry to butt in on this thread ... what about spent char coal , you know the dust thats left of the bar b ?