I agree the waist can be stored fairly easily in the righ location and if the money is spent on building the site.
All this is needed is to sink a vertical shaft in the ground as deap as possible. In an are where it will not be effect by gound water or earth quake activitey.
The run horizontal tunnels of from the shaft at the bottom. Pack in the waist, back fill with concrete the move one level up and repeat the process.
The problem is that any location like this in Australia would require port handeling then a large amout of road freight the wast to the site.
