Stabilizing a quarry where rockfalls threatened to crush critical infrastructure under construction demanded a meticulous approach and required workers to rappel slopes to remove loose material. At a cost of less than $500,000, the design-build project involved an outer highwall corner stabilization for a primary crusher station, mitigating rockfall along the conveyor near the highwall and the installation of six micropile caps to structurally support the dump ramp deck.

In the highwall corner, a bench collapse led to a significant slab breakdown and smaller block failures. A combination of the rock mass jointing and the ripple effect of heavy joint structures created poor conditions that required the team to use rock bolts and a reinforced layer of shotcrete to reinforce the area. In the second area, where rockfalls had occurred over the last year on a 900-ft slope near the future conveyor, crews used scaling techniques to remove loose debris and install rock anchors for additional support, a particular challenge considering work in the upper crest area was constrained. Crews successfully coordinated to stay safe.