DA Smith was commissioned by RESPEC to complete Phase 1 and 2 of a multi-year investigative geotechnical drilling program at the La Prele dam, near Douglas, Wyoming, the oldest and tallest open-front dam in the US. Phase 1 was completed in summer 2021, followed by Phase 2 in summer 2022 and 2023. Both programs included vertical and angled HQ3 core drilling to 300 feet deep, HSA and casing advancer drilling through cobble-laden overburden, SPT sampling, Lugeon water pressure (packer) testing, and downhole televiewer and sonic logging support. DA Smith completed select holes as monitoring wells with piezometers.
Drilling was conducted in the stream channel and from steep roadways and cuts immediately downstream of the dam. Helicopter holes were also drilled in 2022 and 2023. Each year, the drilling campaigns were completed successfully and on schedule before the onset of winter weather.