By the time Tim Currier, the mayor of Massena, New York, found out that Bitcoin miners had set up shop in his small town, it was too late to stop them.

Massena is a border town of about 10,000 along the St. Lawrence River, which provides residents of the area with a wealth of affordable and reliable hydroelectric power. That cheap juice also lured the cloud mining service Coinmint, which illegally moved into a vacant building in an industrial park in January and plugged in a fleet of computers. T…