HELIX Neptune is a 400 kg amphibious robot that excels at water characterization. It normally carries a sonar head on a retractable mount for bathymetric surveys, as well as the ability to deploy in situ characterization tools on a flexible line to a depth of 200 m. Copperstone Technologies has developed HELIX, a family of autonomous field robots to collect mission-critical data in hazardous environments. Copperstone Technologies has modernized the screw-drive vehicle and adapted it to work as a robotic platform specifically for environmental monitoring and tailings investigations. The patented screw drives are pontoons that enable flotation, with a helical grouser acting as a propeller when spun at high speed in the water. At low speeds, the vehicle can crawl through soft mud deposits or act as a wheel on hard ground. HELIX has many advantages over other modes of propulsion and is perfectly suited to the variety of terrain and seasonal conditions encountered on tailings.