2014 - Pond 2 Seepage Barrier Wall | Big Island Mine, Green River, WY
The project is located in the Southwest corner of Wyoming at a fully operational Underground Trona Mine located in Green River, WY. To expand the mining operations, an additional tailings pond was required for the expansion. Due to a thick fractured rock layer, a Seepage Barrier Cutoff Wall was designed around the pond to alleviate environmental concerns that may occur during seepage of tailings while the pond is in operation.
||OCI Wyoming, L.P.
||Barr Engineering Company
The seepage barrier wall was constructed through layers of silty sand, clayey gravel, siltstone and sandstone with a combination of clamshell bucket and Hydromill.
The seepage barrier wall is constructed by the self-hardening slurry method, which includes the excavation through the embankment with a mechanical clamshell, and into the siltstone and sandstone with a Hydromill cutter to a depth of up to 65 ft from the working platform.
A unique feature of the project was the installation of a test panel off the alignment with a large amount of testing which included coring, wall face inspection, joint confirmation and review of wall homogeneity during destruction. This additional work and quality control information provided a baseline for the testing that occurred during production.
Acceptance testing of the seepage barrier wall is performed at 28 days through UCS and Permeability testing of casted in-situ samples. Samples were taken during every shift that work was performed.
Acceptance criteria to be achieved during testing included:
• Permeability < 1x10-6 cm/sec @ 28 Days
• Strength > 75 psi @ 28 Days
To maintain conformance to the stringent requirements of the mix design, real time testing occurred throughout construction at the Batching plant. Additional testing occurred during excavation including verification of panel location, panel depth and panel verticality.
The project was completed ahead of schedule, meeting very high quality control and safety standards to the clients satisfaction.
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