[add info about shell companies, the volatile nature of a speculative industry like mining, the distinction between a "mine" and an "owning company"]
[how to find lists of companies in an area, relationships between companies, etc.] Most evidence of mining companies comes from government regulatory documents. See [gov regulation] page.
university archives:
https://digital.library.mcgill.ca/hrcorpreports/home.htm
https://www.lib.uwo.ca/business/records/index.html (esp annual reports collections
news, archives -- links to these