Helicopter Supported Drilling
The Federal Highway Administration and Arizona Department of Transportation (ADOT) commissioned a study to evaluate the improvement and/or realignment of US Highway 60 from outside of Superior, AZ to outside of Globe, AZ. Significant emphasis was placed on improving the existing route as opposed to realigning the highway for various cost, safety, and tourism reasons.
Mountain Air Helicopters
Crux was contracted by AMEC to provide exploratory drilling for the proposed highway improvement project between milepost 222.6 and milepost 258.0 on US Highway 60. The scope included drilling and sampling 54 borings ranging in depth from 10 to 100 feet, for a combined total of approximately 2,300 feet. 38 of the borings were accessible by track-mounted equipment, while the remaining 16 were deemed difficult-access and required helicopter support.
Eight of the helicopter borings presented specific challenges as they were located within close proximity to the highway and required traffic control during equipment moves. Project specifications indicated that traffic control would be permitted only during week days, so Crux worked closely with the owner to complete the borings in an order that complied with traffic control regulations.
Subsurface conditions encountered during the project presented additional challenges, consisting of volcanic rock with some conglomerate, areas of colluviums, and alluvium consisting of sand, gravel, cobbles and boulders.