(CNN)Hundreds of climate change protesters broke into a huge open cast mine in western Germany Saturday to protest against the country's ongoing dependence on fossil fuels. The activists, many dressed in white overalls, evaded police officers as they crossed fields and roads, before descending into the vast Garzweiler lignite mine, located south-west of Düsseldorf. The mine, which covers 48 square kilometers, is operated by German electricity giant RWE (Rheinisch-Westfälisches Elektrizitätswerk AG) and produces raw materials used in coal-fired power stations.