In 1998, following completion of an expedited removal action of 1.2 million cubic yards of mine tailings, slag material, and impacted soils from the historic stream channel and floodplain of Silver Bow Creek on the east end of Butte, Montana, construction of a demonstration scale treatment plant was completed. This demonstration-scale lime-precipitation treatment system used unlined lagoon cells to treat (initially) ~125 gallons per minute (gpm) of impacted groundwater. The system was operated at the Lower Area One Site within the Butte Priority Soils Operable Unit (BPSOU) in Butte, Montana, until the winter of 2004-2005. Thereafter, the system was expanded to treat a variable influent rate averaging approximately 1,000 gpm of impacted water.
To meet EPA record of decision (ROD) requirements and help complete the ongoing consent decree process, Pioneer upgraded the system to a fully operable, modern treatment facility. Beginning in 2008, this design and construction effort resulted in expanding the system’s treatment capacity to 1,800 gpm. Key site development system features Pioneer completed include designing and constructing the following buildings:
- 792-square foot metal building to house influent water pumps and associated equipment.
- 1,273-square foot wood-framed building to house water treatment/equipment.
- 1,987-square foot metal storage building to house a dredge and portable lime silo.
- 1,054-square foot metal building for office space.
Pioneer also designed a redundant influent pump station, redundant 14-inch high density polyethylene (HDPE) influent lines, and an off-site groundwater elevation control and pump station. We upgraded the system headworks building and lime feed system mechanical components, and designed and constructed a new systems operations building with integrated instrumentation and controls. The controls included a human-machine interface station to actively monitor and adjust system parameters.
Additional improvements Pioneer completed to increase the efficiency of solid waste removal and disposal included designing and constructing a 6-inch HDPE sludge transport line and a concrete multi-cell sludge decanting facility.
