Dames & Moore, 1999 - USDA Forest Service

wilderness boundary with the intent of establishing background metals concentrations (DMSS-26 and 27)
(Figure 3.1-2); these sample locations are approximately one mile from the nearest tailings pile. and are
upwind based on the prevailing wind direction reported in Air Resource Specialists, 1994, and onsite
USFS weather station data. All three samples were collected for metals analyses as presented on Table
3.1-1. The results of the analyses are presented in Sections 5.2.1 and 5.2.3.
3.1.1.4 Maintenance Yard
Four surface (DMSS-8 through 10, and one sample noted as Storage 6") and three subsurface soil samples
(DMSS-8 through 10) were collected in the maintenance yard area, to the northwest of the former mill
,facility (Figures 3.1-2 and 3.1-3). The three subsurface samples were collected at a depth of 2 feet bgs.
The samples were collected for metals, total petroleum hydrocarbon (TPH), and PCB analyses as
presented on Table 3.1-1. The results of the analyses are presented in Section 5.2.4.
Lagoon
One surface (Lagoon 6") and one subsurface soil sample (Lagoon 2') were collected in 1997 from the
bottom of the lagoon feature located northwest of the former mill facility (Figure 3.1-2 and 3.1-3). The
subsurface sample was collected at a depth of 2 feet bgs. The samples were collected for metals, TPH,
and PCB analyses.as presented on Table 3.1 - 1.
In 1998, additional subsurface samples were collected to further assess the extent of chemical constituents
. in the lagoon area. The samples (DMLG-I-2', DMLG-I-4', DMLG-2-4', DMLG-2-7%', DMLG-3-2',
. DMLG-3-4', DMLG-4-2', DMLG-4-4', DMLG-5-2', and DMLG-5-4') were collected at approximately
. 2-foot intervals from test pits excavated on the perimeter and center of the lagoon. Test pits were
terminated when groundwater was encountered. The test pit locations are shown on Figure 3.1-3. The
additional samples collected were analyzed for cadmium, copper, lead, and total petroleum hydrocarbons
(TPH diesel and heavier). The results of the analyses are presented in Section 5.2.5.
Tailings Piles
Referring to Figure 3.1-2, three surface soil samples were collected from each of the tailings piles for a
total of nine samples (DMSS-I 1 through 19). The samples were collected for metals analyses as
presented on Table 3.1 - 1.
Subsurface soil samples were also collected from the tailings piles during the excavation of trackhoe
excavated test pits and trenches completed both on top and near the base of tailings piles slopes. The
following samples were collected during the excavation of the test pits and trenches: four samples from
tailings piles 1 (DMTPI-2, DMTPI-3A, DMTPI-38, and DMTPI-4); three samples from tailings pile 2
(DMTP2- I A, DMTP2- I B, and DMTP2-2), and seven samples from tailings pile 3 (DMTP3- I, DMTP~-2,'
DMTP3-3A, DMTP3-3B, DMTP3-4A, DMTP3-4B, and a duplicate sample, DMTP3-4AX). The samples
were all collected for metals analyses as presented on Table 3.1-1. The results of the analyses are
presented in Section 5.2.6.2.
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17693405-019Uuly 19, 1999;2:07 PM;DRAR FINAL RI REPORT