Abstract: Upon completion of dislodging and transporting mine material from an underground mine, the mine is converted to a repository for the disposal of hazardous waste. The mine includes a network of connected chambers each formed by surrounding sidewalls into which parallel spaced boreholes are drilled to dislodge mine material from a seam in the rock formation. For use as repository, each borehole is lined with a layer of water permeable material. Drums containing hazardous waste are encapsulated within spherical cement modules. The modules are positioned in spaced relation within the boreholes. Shock absorbing reinforcing material fills the voids within the boreholes surrounding the modules to protect the modules from damage due to seismic disturbances in the underground formation. Each of the cement modules is ventilated to dissipate heat through an air plenum into the central chamber.