Atkinson installed 950 structural steel arch supports in two existing openings leading into the limestone mine—which remained fully operational during construction. The steel arch supports were placed every four feet along a declining 17 percent sloping grade. Atkinson also installed substantial steel and concrete structures at the intersections of 10 cross passages between the two access excavations. Approximately 17,500 cubic yards of concrete and cementitious backfill were placed behind the steel supports and against the in-place ground to provide continuous support of the loose ground above.

Atkinson's scope of work included other preparations and construction. This included removing and reinstalling high-voltage power lines as well as installing a water piping system to supply and discharge water during mining operations. Our crews removed and reinstalled a 4,000-linear-foot, 60-inch mainline conveyor belt used to transport crushed limestone out of the mine to increase the efficiency of the conveyor system.