Acid mine drainage poses a significant environmental challenge resulting from mining activities. It can occur during and after the exposure of sulfide minerals to water, oxygen, or oxidizing bacteria. Extensive copper ore exploitation, processing, and the deposition of substantial amounts of mining waste have caused severe geological, hydrogeological, and geomorphological changes, including soil contamination, as well as local or even regional-scale pollution of rivers and groundwater. This study focuses on the utilization of waste mine waters and unbalanced portions of the mine deposit, such as flotation tailings, to transform their negative characteristics into environmentally friendly ones. In previous research by the authors, acid mine water from Robule, a part of the Bor copper mining and smelting complex in Serbia, was effectively treated using flotation tailings, resulting in a solution suitable for safe discharge. This paper investigates the characteristics of the solid residue remaining after the treatment of modified flotation tailings to assess the feasibility of its safe disposal back into the environment. Standard procedures such as TCLP and EN 12457-4 tests were employed to evaluate the leaching characteristics of the solid residue. Additionally, the residue underwent long-term leaching with melted snow to simulate environmental conditions over one year, and the drainage water was analyzed and compared with the results of the standard leaching procedures. The investigated treatments demonstrate improved economic and environmental outcomes, with a process tailored to environmental preservation.