The variation of carbon dioxide in the Cospuden–Zwenkau dump, in the southwest of Leipzig in Saxony, Germany, is caused by a variety of reasons, some having to do with the different types of residual mining spoils used as lower and upper dump materials, and some having to do with the dynamical evolution of conditions both within the dump and externally as time progresses.
The purpose of this article is to show how one can quantitatively handle such variations of external and internal conditions, even when one does not know with precision whether, for instance, a leak exists and the fraction of gas it can leak. Nevertheless, one can construct model behaviors that allow the exploration of the probable consequences of such likely leaks. In addition, the variation of the lake-level pressure, the variation of the seasonal swing of temperature, and the variation in the availability of the supply of carbon dioxide are all factors that one can investigate to determine their influence on the saturation of carbon dioxide in the dump waters, the amount of free-phase gas that one anticipates to be in the dump, and the potential loss of carbon dioxide from the dump to the atmosphere. Results of such investigations are presented here so that one can determine the influence of each factor in the potential release of carbon dioxide and also the residual free-phase gas still trapped in the dump, as well as the amount still in solution with water. The general procedures are applicable to any dump involved in carbon dioxide generation and/or release.