Developing the project
A four-phase plan to reclaim the rock pile was prepared by Chevron Mining’s lead engineering consultant, Norwest Corporation, and was approved by the New Mexico state regulators.
Constructing the project
The work area was almost one half mile in length, with slopes ranging from 38° to 45°. With project safety of paramount concern, continuous monitoring was undertaken to measure displacement, groundwater conditions, and meteorological conditions. The plan’s Phase 1 entailed processing, haulage, and placement of 20,000 cubic yards of drain rock under what would become the toe of the stabilized pile. Phase 2 called for mass excavation of more than 500,000 cubic yards to form an initial buttress in the toe area of the existing rock pile. The cut materials
were moved down the face of the rock pile to build a stable buttress fill at slopes ranging from 2:1 to 2.5:1 (H:V). Phase 3 construction consisted of removing and redistributing the top of the rock pile by excavating about 800,000 cubic yards of it down to native ground. These cut materials were used to form stable slopes at 2:1 to 3:1 (H:V) for the remainder of the buttress fill. Phase 4 consisted of creating drainage controls to protect the re-graded surfaces. The project was located in the rugged Sangre de Cristo Mountains of New Mexico at an elevation of 10,000 feet.
Work was completed without a recordable safety or environmental incident.