East Boulder Mine – Stage 2 Tailings Storage Facility

Stillwater Mining Company
Nye, Montana

The project work scope included clearing, stripping, and grubbing 30 acres, removal of surface soils/unsuitable material, embankment foundation preparation, excavation/embankment, processing/placement of sand and gravel (basin underdrain and erosion protection), subgrade preparation, liner bedding, excavation/backfill anchor trenches, installation of geotextile cushion layer/geotextile and 100 mil HDPE geomembrane in basin/HDPE geomembrane, installation of a permanent wind ballast, installation of 4-inch HDPE collection headers and fittings and 3-inch CPT basin underdrain collection pipes and fittings, installation of the basin underdrain collection structure, mass concrete, installation of piezometers and surface movement monuments.