Coal Combustion Residual (CCR) Dewatering at Jim Bridger Power Plant

Project Location: Point of Rocks, Wyoming

Owner: PacifiCorp

GC: Bodell Construction

Engineer: AECOM

Project Revenue:  $450,000.00

Project Timeline: 2015

Summary:

Dewatering solutions for the renovation and upgrades of the Coal Combustion Residual

(CCR) holding ponds at the Jim Bridger power plant.

The Challenge:

This project involved dewatering to allow for the excavation of three Coal Combustion Residual holding ponds as well as dewatering to allow for the excavation of new concrete holding basins at both ends of the existing CCR storage ponds.

The Solution:

Griffin designed an eductor dewatering system, totaling 1800 ft., which included four (4) separate operating eductor pump stations. The systems were used to lower the piezometric water level to 17 ft. below existing grade. This was necessary for both the excavation of the existing coal residuals in the three existing ponds and for the construction of the new concrete holding basins that were built to replace those ponds. The material from the existing ponds was hauled off site for disposal.

The Griffin Difference:

Time was of the essence on the project and the Griffin Team mobilized and installed the system in just over 30 calendar days. The four individual systems were brought on line separately in a manner that allowed the Contractor to construct the two new concrete basins initially and then start removal of the CCR material from the existing lagoons.

The dewatering facilitated completion of the concrete basins, removal of the CCR from the existing ponds, and backfilling in a period of approximately 60 days from start to finish.