South (back) side of GPMTCP/GCP. There are 3 8 inch vent pipes on the left (1 is very short), the two on the right are 12 inch diameter and had valves to seal them off. The arrow is pointing to the approximate location of the remaining section of the left air intake pipe. There was a second one on the right side, but the end of that one is nearly totally buried.

Photo album created with Web Album Generator