Acidification is a universal problem at all mining sites in which oxygenated water comes in contact with sulfide minerals or other reduced sulfur compounds. An International Workshop was held in September 1995 at the Department for Inland Water Research of the UFZ-Centre for Environmental Research in Magdeburg on the limnology of lakes created by open-cast lignite mining, emphasizing the often observed geogenic acidification after oxidation of pyrite. The volume has 25 chapters including a chapter with results of group discussions about the topics mentioned above and further problems that were identified during the meeting. The monograph gives a baseline of the state of science on the worldwide problem of geogenic acidification of lakes following human mining activities.