Annika Jacobson, head of Greenpeace Sweden told Radio Gotland that the activists will do everything they can to stop trees from being felled.
The Swedish Society for Nature Conservation has also called on the government to make the area around Ojnare forest a natural park and claims that the mine breaches European Union environmental rules.
Sweden’s Green Party and the Left Party support the demands.
On Friday the EU Environment Commissioner Janez Potocnik said the European Commission was looking into the case.
Nordkalk, the company responsible for the mine rejects the criticism from environmental groups and says the mine will only have a minimal impact.