. The historical hard coal mining area of the districts of Zwickau and Lugau/ Oelsnitz in Saxonia (Germany) is a source of heavy metals and arsenic polluting the adjacent ground- and surface waters. Heavy metals and metalloids like Zn, Cd, Ni, Co, As and Mn are transported, partially as fine precipitates, to the adjacent river Zwickauer Mulde and with that to the river Elbe. Some of the dumps are partially older than 150 years, and some of them were remediated more than 50 years ago. Today we still can learn from the more or less successful remediation measures after some decades of application. In this paper, three different dumps are presented and differences between their remediation measures and the long-term success of it shall be pointed out. As a result, especially a sealing and covering of a dump turned out as very successful for the prevention of AMD generation. A further utilization of such a remediated and revegetated area is possible, or it can be “given back” to the nature. In contrast, a revegetation without covering results in a long-term AMD-generation of such a mining dump site.