Since 1681, gunpowder has been officially introduced for mining. Mining in the particularly hard Kongsberg Mountain is energy intensive, so the silver mine continues to develop technology throughout the operation to reduce production costs. A large artificial dam powers the mine's hoisting system before electricity is introduced. In 1624, a road from Hokksund to Kongsberg was built to serve the Kongsberg Silver Mines, the most important road built in Norway in the 17th century. In 1665, the road was extended to Kristiansand and Larvik.