In an emergency response to the rockslide on the Glenorchy-Queenstown road in May 2010, we intervened during the week-end to test the rock stability so that it reopened the following Monday (read the Otago Daily time article).
The helicopter dropped us off above the cliff, we scaled all the loose rocks. Then, we anchored the large rock of concern, so that a digger could tug it from the road with a cable. When no movement was observed, it was deemed safe enough to reopen the road, once cleared.