CENTRAL ARIZONA
Pinto Creek Diversion Channel
PROJECT DESCRIPTION
The Pinto Creek Diversion Channel (PCDC) project at a mine site in Central Arizona was undertaken to replace the existing channel slope lining system that had been damaged during a storm in 2021. The lower portion of the existing system consisted of articulated concrete block (ACB) panels overlaying
geosynthetics and a compacted soil underliner. The upper portion consisted of a soil-cement embankment. Odin constructed a new soil-cement embankment that spans the entire length and depth of the channel, approximately 4,512 feet long and 21 feet deep.
Odin’s scope of work consisted of, but was not limited to, establishing a safe and efficient working environment; installing erosion and sediment control features; setting up a soil-cement plant (pugmill) and staging and material stockpile areas; performing clearing and grubbing; managing baseflow and stormwater through the PCDC during construction; demolishing and relocating/staging selected existing site features; and placing the specified soil-cement embankment.
Work related directly to the replacement of the channel lining system began with demolishing approximately 5,000 cubic yards of the existing channel lining system, excavating approximately
113,000 cubic yards of unsuitable subgrade material, and removing and disposing of the soil-cement overlaying the ACB panels. Approximately 6,000 cubic yards of excavated soil-cement, ACB panels and blocks, and geosynthetics were disposed of on-site.
Borrow operations to support soil-cement production included excavating, hauling, crushing, and screening more than 100,000 tons of onsite material. Odin erected an on-site pugmill plant to produce soil cement. The pugmill was used to process defined volumes of soil, cement, and water to produce the specified material for placement within the channel. Material was transported from the pugmill to the work areas using articulated haul trucks.
The soil-cement embankment was installed from south to north and east to west. Soil cement was placed in lifts from the floor elevation to the upper channel crest elevation. Each lift was placed and compacted using skid steers and remote compaction equipment. Each lift varied in width from 8 to 12 feet, per the design, and the final slope was constructed to a 2:1 side slope. Immediately following completion of the soil-cement embankment, the access road safety berms were reinstalled at the top of the channel slopes. The auxiliary berm on the pit side was repaired where necessary to raise areas lowered by construction activities. The work also consisted of placing reinforced cast-in-place concrete slabs and 13 grade control structures, regrading alluvium within the channel, and
reestablishing access roads and the transition of the PCDC channel modifications into the upstream and downstream limits of Pinto Creek.
Baseflow and stormwater management was critical to ongoing operations within the active channel. Weather and forecasts were monitored daily and work activities adjusted or revised accordingly for anticipated weather conditions. Both baseflow and stormwater were managed by auxiliary berms, controlled work areas, and diversion channels constructed to manage precipitation events.
MEETING PROJECT CHALLENGES
The Odin team met numerous project challenges including the remote site location, limited work area, site hazards, strict quality control requirements, material delivery, and subcontractor management.
• The work within the mine site was conducted along a one-mile stretch of channel with extremely limited access and working area for hauling and construction equipment. Odin addressed these challenges by planning the work with specific hauling routes, entry and exit procedures, sequenced placement areas, and signage.
• Biological hazards such as venomous snakes, scorpions, and spiders were recognized and proactively addressed with comprehensive site-specific safety orientations provided by both Odin and the client that focused on identifying and avoiding these hazards. Crews were trained to employ PPE and to avoid clearing debris or vegetation by hand, instead using tools to prevent accidental contact with hidden wildlife.
• Work was conducted in a desert environment with temperatures frequently exceeding 100 degrees. Odin implemented a Heat Illness Prevention Plan that included scheduled hydration breaks, shaded rest areas, and regular breaks. Work was scheduled to minimize exposure during peak heat hours. Site leadership monitored high-temperature days closely, adjusting workloads and break frequencies to ensure worker safety.
• Daily Job Safety Analyses (JSAs) and regular site inspections were conducted to assess wildlife and environmental hazards. These assessments included verifying that proper controls were in place for the day’s tasks. To ensure readiness in the event of an emergency, multiple employees were certified in First Aid and CPR. Additionally, the client maintained an on-site emergency response team equipped to handle wildlife encounters or medical incidents requiring immediate attention.
• Strict quality control requirements were addressed by increasing the onsite QC staff, detailed data tracking and documentation, and close coordination with the Owner and the design engineer.
• Material delivery and coordination challenges were managed and scheduled around highway road closures (approximately 8 months duration); supply chain issues were managed with advance planning and communication with suppliers.
• Subcontractor management challenges were addressed with close supervision and oversight, thorough data review and analysis, and communication and coordination with on-site subcontractor personnel.
Project Highlights
• Soil cement production in an MSHA mine
• Restoration of an existing diversion channel
• Crushing, screening, mixing of on-site provided materials
Project Details
START DATE:
August 2024
END DATE:
March 2025
VALUE:
$14.7M
