I do greatly believe that the central quarry field that is located south of the Khafra causeway,..was not the qurry that was used for extracting the stones to build the Great Pyramid. Reason: it is very stupid to expand ones energy to haul up 5 to 2 ton blocks up the quarry then up the pyramids. I do believe that the main quarry used for extracting the limestone core blocks and the limestone building blocks were quarried at a higher level such as from the higher grounds west of the Khafra pyramid. You may need half the energy to push stones down then haulling them up. I am sure that is how the project managers saw it. Decreasing the energy needed,..means decreasing the size of the labor force,..means decreasing the cost,..means the abiity to succeed in accomplishing the task. One would use gravity as a tool to help,..other then struggle against it. This western quarry must exist ,..but covered by sand.