From Longman Dictionary of Contemporary Englisha mine of information (about/on something)a mine of information (about/on something)KNOW somethingsomeone or something that can give you a lot of information about a particular subject and that is therefore very useful or helpful The website is a mine of information about all forms of cancer. → mine
Examples from the Corpus
a mine of information (about/on something)• Study a local map and the Ordnance Survey, which is a mine of information.• A trip to Brussels to meet the responsible officials can turn up a mine of information.• If used properly, the diary was a mine of information.• His column in the Angling Times was the first thing that I turned to and what a mine of information. 