Layland Canyon Mine Reclamation
High Wall Interface Compaction & Water Control for Slope Stabilization
URETEK ICR Rocky Mountain, a division of Concrete Stabilization Technologies, Inc. (CST), completed a high profile in situ compaction and water control project at the Layland Canyon Phosphate Mine in western Wyoming.
The Layland Canyon Mine area is an abandoned mountainside phosphate mine located in Lincoln County, near Cokeville, Wyoming. The mass grading and reconstruction of the slope area of the mine was being completed as part of the State of Wyoming’s reclamation of abandoned mine land.
URETEK ICR Rocky Mountain, sub contracted with Oftedal Construction, Inc. to perform the injection of expanding structural polymer into areas of the high wall face of the mine, in order to help sheet water off the zone next to the face by compacting the soils and mitigating the settlement and water inflow into the backfill and rock interface. With the topsoil being placed over this area a desired shingle effect was created beneath to divert water and help control future erosion of the reconstructed area.
Regional engineer Roy Mathis worked with Chris Walla, P.E., of RESPEC Consulting to develop the procedure and specification for injection of expanding structural polymer that was successfully used on this project. Crews joined Oftedal Construction for a site specific safety meeting, and then drove to the injection location to begin placing probes and prepping the URETEK injection equipment. After a field adjustment by AVI’s Field Engineer the first set of injections were placed on the North end of the high wall, 11 feet south of Station 17+70, 59 feet north of the original plan.
Due to wider top bench, injection points were moved 30 to 40 feet North of the original injection plan. URETEK’s structural polymer injection design was adjusted from three injection rows, to two rows. With the second row adjusted with increased material per injection location in order to ensure good compaction and the material spread between injections into the backfill and against the high wall. Injections were made at three foot and 10 foot depths.
URETEK ICR Rocky Mountain crews were highly efficient in completing the project and devising the best solution based on actual field conditions once the work began. In consideration of water runoff, adjustments were made to meet the goal of shedding water away from the high wall. Slope changes were taken into account and injection points altered from the original 2 foot area to 4 foot along the slope wall in order to provide maximum effect from the stabilization of the soil. Adjustments to compensate for blowout were also made at the ten foot level.
The URETEK’s structural polymer was injected into the high wall area of the mine site, successfully compacting, stabilizing and providing erosion protection for the abandoned area. Even as inclement weather rolled in, the work was completed in three days. A total of 1,100 lineal feet of compaction and water control was completed at the interface of the high wall and fill material to assure stabilization of the soils and provide excellent results for the successfully reclaimed mining site.
Project Team Members:
State of Wyoming DEQ Abandoned Mines Lands Division, Owner
Jim Murphy, P.E. AVI Engineering, Inc.
Chris Walla, P.E., Environmental Manager, RESPEC Consulting & Services
Roy Mathis, CST Consultant & CST Project Manager, CST, Inc.
Matt Otterby, Project Manager, Oftedal Construction, Inc.
Tomas Ramos, Project Superintendent, CST, Inc.
About this URETEK Affiliate
URETEK ICR Rocky Mountain (CST) specializes in improving the weight-bearing capacity of subsurface soils through the injection of patented, lightweight, expanding structural polymers. The patented URETEK Deep Injection Process® provides the industry’s most cost-effective, quickest and safest solution for soil stabilization and densification at depth without excavation. For 30 years, URETEK has safely completed more than 85,000 projects leveling, lifting, sealing and stabilizing structures of all sizes for commercial, residential, and governmental clients. URETEK ICR Rocky Mountain operates in Colorado, Utah, and Wyoming with offices in Denver, Salt Lake City, and Wheatland.
ABANDON MINE DANGERS
Many of the dangers posed by these sites are not visible from the outside. Below is an overview of the numerous hazards that these abandoned mine sites pose.
Horizontal openings: The mine opening (known as a portal or adit) may seem stable, but rotting timbers and unstable rock formations make cave-ins a real danger. The darkness and debris in old mines make it difficult to identify the hazards.
Vertical shafts: These can be hundreds of feet deep. At the surface, openings can be hidden by vegetation, or covered by rotting boards or timbers. Inside old mines, shafts can be camouflaged by debris, or hidden by darkness in the mine.
Explosives and toxic chemicals: Blasting caps, dynamite and chemicals were often left behind when the workings were abandoned. Explosives become unstable with age and can be detonated by the vibration of footsteps. Abandoned chemicals such as cyanide, arsenic, mercury and other deadly toxins may be present in leaking and deteriorating containers.
Dangerous gases: Lethal concentrations of methane, carbon monoxide, carbon dioxide and hydrogen sulfide may accumulate in underground passages. Oxygen deficient air may cause suffocation. People have died within a few feet of mine openings.
Water: Impounded water may be highly alkaline or acidic (resulting in skin burns), as well as deep and cold (contributing to hypothermia).
Spoils (rock and dirt) piles: These loose piles can collapse or slide, burying an unsuspecting victim.
Equipment and buildings: Abandoned surface structures and old mine equipment may collapse on bystanders.
Highwalls: These are the excavated vertical cliffs in surface pits and quarries. They can be unstable and prone to collapse. Highwalls may not be visible from the top, presenting a danger to off-road drivers.
Radon: Radon is a natural radioactive decay product, and is known to be a factor in some lung cancers. Radon can accumulate in high concentrations in poorly ventilated mines.
Wildlife: Rattlesnakes, bears, mountain lions and other wildlife frequent old mine sites.
Disorientation: There is no natural light inside mine workings. Many workings meander randomly because the miners who dug them followed an ore vein. It is easy to become lost and disoriented in a maze of mine workings, especially if lighting equipment fails.
Mine Fires: Mine fires create surface hazards in abandoned coal mine areas. As fires burn within the seam, fissures can open to the surface delivering deadly gases into the atmosphere. The area around the fissure may not be capable of supporting the weight of a human or vehicle, and may collapse into the burning coal or the mine void.
For more information on mine safety, visit the U.S. Department of Labor’s Mine Safety and Health Administration Stay Out! Stay Alive! website.