The anthropic activity, especially the one from the mining industry has an important impact over the environment, by massively degrading the ecosystems, reducing them including the biodiversity as well. The influence upon the environment factors starts at the same time as the preparation and exploitation does and this goes on and gets bigger at the same rate as the productive activities are developing. In some cases the negative influence is to be seen a very long time even after the entire productive activities stop in that area. The mining industry creates a source of polluting factors such as: heavy metals: lead, zinc, copper, cadmium, arsenic, mercury; cyanides, sterile after processing and so on. In the present paper we will expose the long term negative impact on the ecological equilibrium generated by the Leşu Ursului mine which has exploited non-ferrous metals for decades from Brosteni and Crucea in Suceava county and propose ecological rehabilitation methods.