In Tucson, Arizona, a new engineering design improves the Speedway Boulevard corridor, from Camino de Oeste to Painted Hills Road, from a two-lane road to a modern three-lane urban collector roadway with paved shoulders. Improvements include horizontal and vertical geometry, intersection realignments, traffic control elements, improved drainage conveyance, pedestrian and bicycle facilities, a new bridge over an existing wash, and ADA accessibility.

The new design improves public safety with the elimination of substandard curves and line-of-sight conditions, and the addition of a continuous center turn lane for improved access and reduced traffic congestion, bicycle-accessible paved shoulders, and an ADA-accessible pathway.

Engineering work addressed roadway design, traffic analysis, hydrology and channel hydraulics, geotechnical analysis, pavement design, bridge design and other structural elements, utility relocations, environmental requirements, construction considerations, cost estimating, and scheduling.

The device designed is a mixer-settler that mixes hydrophobic solvent with an aqueous media that contains the metal needing to be extracted. The mixer-settler can separate a large amount of metal from the aqueous mixture in a relatively short amount of time. Calculations were carefully made to scale and optimize the function of the device. A 3D-printed plexiglass model helped with observing the mixing process and making appropriate changes. Testing and analysis improved the device’s capability. Extraction entraining with hydrophobic fluid is expensive. The mixer-settler design uses less hydrophobic fluid and shows a lot of promise for use in the future of mining.