About 10,000 measurements were taken. Fifteen holes were drilled specifically to study dissolution features. These drill holes included drill hole ERDA 10 in order to study deep dissolution and 6 drill holes in Nash Draw in order to study shallow dissolution. Other boreholes were drilled to study specific features other than dissolution. This survey technique responded to density variations of the rocks and changes in elevation.
Sinkholes have low densities.
A geological log is created when a geologist on-site logs the cuttings that are returned to the surface in the drilling fluid. The log does not show a perfect picture. Sending electronics down a drill hole may make various measurements. Because salt rocks are highly soluble, the DOE had to be sure the site was in an area where solution from the surface would not attack the underground site. The facility horizon was selected and the DOE studied the formations in the shafts.