Injection of slurried wastes is carried out within deeply buried strata. Appropriate target strata are identified in terms of sufficient porosity and permeability, and overburden that includes permeable and impermeable strata. Slurry is injected at sufficient pressure to establish fracturing within the target strata. The injection pressures and the resulting waste pod are monitored by a suite of monitoring procedures, including bottomhole pressure and surface uplift. The injection is carried out in a series of injection episodes separated by interinjection episodes. Apparatus for preparing and injection the slurry include a mixing chamber, a partly encased well and a bottomhole pressure gauge. Process monitoring apparatus controls the operation of the system.