s&r your own link tells you that the term Candyman was contemptuously applied to the strikebreakers to which you refer. The more common use of the term, and the reference in Cushie Butterfield, is another name for a rag and bone man (certainly the image that Tommy Armstrong gives in his songs about strikebreakers -"South Medomsley" and "Oakey Strike Evictions")who would sound his trumpet to make the neighbourhood aware of his presence. Thus the wonderful expression "you ought to be shafted with a ragman's trumpet". The muckman mentioned in the song would be a refuse collector - a latterday bin-man. "Cushie Butterfield" is a very popular North East song and it does not need to be affilliated to either the mining industry or the seafaring trade to achieve that honour.