Laserfiche WebLink
Environmental Protection Plan, Schwartzwalder Mine 7-2 <br />• Rule 6.4.20(7)(e) because it does not contain any designated chemicals and it operates under the existing <br />Radioactive Materials License. <br />(b) Waste Rock Piles <br />Two reclaimed waste rock piles are associated with the mine. The East and West Waste Rock Piles are <br />located adjacent to Ralston Creek, upstream (west) of the mine. Reclamation of the waste rock piles has <br />been successfully completed, and no impacts to water quality in Ralston Creek are detectable from the <br />waste rock piles. <br />The footprint of the east and west piles at the end of mining (2000) are shown in Figure 2-2. In total, the <br />two piles contain have combined footprint of about 6.3 acres (Figure 2-1). The east pile is larger (about 4.0 <br />acres) than the west pile (about 2.3 acres). Material contained in the waste rock piles includes lime-silicate- <br />hornblende gneiss, garnet-biotite gneiss, mica schist, and smaller amounts of quartzite, pegmatite, and vein <br />material derived from the underground mine and ore-sorter reject rock. Reclamation included capping with <br />3 ft of rock cover, then topping with surface soils and revegetation using the seed mix specified by DMG <br />(now DRMS). <br />Evaluations related to the closure of waste rock piles include stability, geochemical characterization of <br />waste rock, and water quality in streams and groundwater adjacent to the piles. The stability of the piles <br />was summarized in the mine closure hydrology report (Whetstone, 2007). The geochemical characteristics <br />of the waste rock piles are discussed in detail in Section 14(a). The water quality in Ralston Creek above, <br />below, and adjacent to the piles is discussed in Section 11. <br />The waste rock piles are not designated as an Environmental Protection Facility subject to the provisions of <br />Rule 6.4.20(7)(e) because the geotechnical and geochemical characteristics indicate that the waste rock <br />• piles are capped and stable, have low potential to generate acidic drainage (Section 14(a)), have produced <br />no discernable impact to Ralston Creek (Section 11). <br />(c) Alluvium and Fill Material <br />Prior to the construction of mine facilities, waste rock from the mine was placed as fill material in the <br />valley adjacent to Ralston Creek. The fill material covers an area of approximately seven (7) acres, and <br />Ralston Creek was diverted toward the north side of the canyon to make room for mine buildings and <br />facilities. Although those facilities have been removed, the fill remains in place in the valley floor and has <br />been reclaimed. <br />The composition of the fill is similar to the waste rock piles. During reclamation, additional fill was mined <br />from the Black Forest Mine (east of the Schwartzwalder) and used for cover and fill material in the valley. <br />Rock from the Black Forest Mine is a hornblende gneiss (LSHG) unit, assumed to have the same chemical <br />composition as other LSHG samples that have been analyzed from the site. <br />Groundwater quality in the alluvium and fill is discussed in detail in Section 9(b)(ii). The fill material may <br />be acting as a secondary source of uranium loading to Ralston Creek (Section 11(c)). Partial source <br />removal of the alluvium and fill is slated to occur in 2010, as described in Section 15. <br />(d) Flooded Underground Workings <br />As described previously in Section 1, the Schwartzwalder Mine was kept dry during operations by pumping <br />water from the lower levels of the mine. Water was collected in the 19 Level, pumped to the 7 level, and <br />then pumped to the surface where it was sent through the water treatment plant before being discharged to <br />Ralston Creek. Pumping rates from the underground mine were very low (140 to 310 gpm) for a mine of <br />this size and depth, indicating that the bedrock has very low permeability (Whetstone, 2007). <br />n <br />LJ <br />4109C.100731 Whetstone Associates