Brazilian President Michel Temer has signed a decree allowing a nature reserve in the Amazon rainforest to open for mining. Located in northern Brazil, the 47,000 sq.km Copper National Reserve (Renca), which is about the size of Switzerland, is rich in minerals like gold, zinc, phosphate, and manganese, reports Xinhua news agency.

The decree, which was also signed by his minister of Mining and Energy on Wednesday, cancels the park’s status as a national reserve. However, it still calls for “the application of specific legislation regarding the protection of native vegetation, nature (and) indigenous border lands and zones”.

The park includes nine different protected zones, two of which are indigenous lands where mining is completely banned, but at least four other zones appear to be accessible to regulated mining activity. Environmental activists say paving the way for mining at the park could exacerbate existing conflicts between mining companies and indigenous groups. Renca was created in 1984 to prevent mining activity from excessively encroaching on wildlife and indigenous communities.