When the locomotive that came to rest inverted over the pipeline was removed by SP, Calnev personnel observed that the entire top of the locomotive had been sheared off and that it had been resting at grade level. There was nothing visible protruding into the ground. Calnev, however, decided to excavate the portion of the pipeline that had been under the locomotive. Using a backhoe equipped with a 24-inch bucket, Calnev personnel excavated an area approximately 80 feet in length parallel to and about 2 feet east of the pipe to a depth about 4 inches lower than the depth of the pipe in the area. Pipe depth was reported to have been about 8 feet at the southern end of the excavated area and 6½ to 7 feet at the northern end. According to Calnev personnel, the soil surrounding the pipe was removed by hand so that the pipe was exposed from the 6 o’clock position to the 2 o’clock position facing south (see figure 4, excavation # 1). Calnev’s manager of operations testified that he personally entered the excavation, inspected the pipe, and found no damage to the coating or to the pipe.
Calnev officials then decided to excavate in an area north of the breach where, according to Calnev’s manager of operations, "…bulldozers had been repeatedly going off the end of the haul road" (figure 4, excavation # 2). According to the Arizona Pipe Line Company foreman, who performed the excavation, about 1 foot of pipe length was exposed from the 1 o’clock to 3 o’clock position looking north. When asked if any damage to the coating or pipe was noted, the foreman replied, "Couldn’t really tell by a visual look, and we didn’t bother exposing anymore due to our objective was to determine depth and alignment of the pipeline at that time." The depth of the pipe at this location was determined to be about 7 feet. With respect to the depth of the pipe, Calnev’s manager of operations testified, "…it was sufficient to where I was no longer concerned about any damage from the bulldozer activity."
By late afternoon on May 15, the wreckage had been removed and SP began to demolish the houses that had been damaged during the derailment. SP planned to close the breach that evening, relay their tracks, and begin removing the trona on the following day, May 16. According to Calnev officials, it was at this point that they began to formulate the next step of their inspection plan. Calnev understood that if SP began removing the trona on Tuesday, inspection of the pipeline would be delayed until the trona removal was completed. According to Calnev’s manager of operations, "At that point, we were still unsure of the integrity of the pipeline. It was still in a stable situation. It had not lost any pressure nor were there any signs of leakage. But yet we could not verify the integrity of the pipeline before then." Calnev’s plan was to move in additional equipment, remove all the trona over the pipeline down to native soil, and excavate and inspect the pipeline at any location where debris was found and appeared to have penetrated the native soil. According to Calnev officials, by removing the trona from over the pipeline, SP personnel would not have to work directly over the pipeline when they began hauling away the trona on the following day. According to Calnev’s manager of operations, this plan was discussed with SP officials and the incident commander, and no recommendations or modifications to the plan were suggested.