Any company who wants to start a mine can apply for permits at the Mining Inspectorate of Sweden (such as an application for an exploitation permit (Sw. Bearbetningskoncession) and the County Administrative Board reviews environmental matters within this process. The municipality has a say in zoning permitting and the Environmental court designated handles the application for an environmental permit.
A permit process including all these steps can in total take 5-10 years.
Source: SGU, “Mineralnäring och samhälle Hur en gruva blir till” http://sgu.se/mineralnaring/mineralnaring-och-samhalle/hur-en-gruva-blir-till/