Well according to court documents as mentioned below, it is known that they were in mining stocks. If the Donald mentioned in your post is the same Donald Ruzzuto from the crime family, there could be a link there?

http://www.theglobeandmail.com/news/national/tax-refund-mystery-is-latest-of-montreal-crime-familys-many-links-to-officialdom/article14548776/

PUBLIC WORKS

According to other court documents, the Rizzuto family didn’t just exploit traditional rackets such as drug trafficking, extortion and loan-sharking but also pushed into mainstream ventures, for example rigging public contracts and mining stock.