Hi Gordon. You've very nearly answered all of my questions there.
How long to build each one given the distance from the (known?) quarry to the pyramids? How often would one of these ramps fail? How long to repair a major breakage? I know figures for these would be impossible to state definitely, but really worst case scenario has to be factored in to any study.
Also, what happens when the stone reaches the pyramid? The angle of the sides means the upper surface is obviously moving away from the final ramp/lifting station. Do you envisage a series of lifting stations up the side of the pyramid, with a new one added as each level is added? It would work, but how long to consturct each new piece? I suppose these could be built in kit form as each layer is being added and the erected quite quickly when needed. That way it's just extra carpenters, not extra time that is needed.
Each stone obviously has to be moved into place when it does reach the pyramid. Can this part be done and keep up with the number of stones being delivered?
As I said previously, a really fascinating idea.