The mafia makes money off of construction projects (usually the governmentally funded projects) in many different ways.
First, they can control the companies, like Masserone Construction, that supply labor or materials to complete a project. The Mafia uses its influence (read money) to help the company it owns (or controls) to win the bid to provide certain materials or labor to the project; they essentially bribe their way into the project. Then, once they win the bid, they charge inflated prices for material and labor, including the use of "phantom" or "no-show" laborers. The mafia can also steal construction materials left on site and sell them to other construction companies/projects.
So a guy like Jack Masserone and his company are in bed with the mob to get public contract jobs and the price of the mobster's influence is money for nothing. All getting funded by your tax dollars, with very little accountability. This is one reason that government funded constrcution projects are notoriously always millions and billions of dollars over-budget.
I'm sure that there are other tricks for the mob to make money with guys like Masserone, but these are the most well-known and prevalent methods.