2016-05-03_PERMIT FILE - C1981008A ‎(19)‎

• Permit No: C1981008A
• IBM Index Class Name: Permit File
• Doc Date: 5/3/2016
• Doc Name: SOIL RESOURCE INFORMATION
• Section_Exhibit Name: Section 2.04.9 Soil Resource Information
• Media Type: D
• Archive: Yes

Samples were collected from hand -dug pits, three-inch diameter auger holes or backhoe trenches
that were dug at all soil sampled sites. The sampled soil material was placed in clean, labeled,
polyethylene plastic or Tyvek® bags, and was kept cool and as dry as possible to limit chemical
changes. The upper horizons of many profiles were moist upon sampling and were air dried prior
to shipment to IML in Sheridan, Wyoming (1988) or Colorado State University (1996 and 1998)
for analysis. Each sample was split at the laboratory with one portion being used for analysis and
the archival portion retained for additional tests, if necessary. The analysis of the samples is
shown in Attachment 2.04.9-8.
11. Evaluation of Soils for Reclamation Potential
The soils and parent materials on the study area were rated for quality based on criteria presented
in Table 2.04.9-2, Criteria for Evaluating Soil Quality. These criteria were approved by DRMS
in the Permit Amendment for the expansion west of 27.00 Road. Recommended topsoil salvage
depths were generated for each sampled pedon and each component of a mapping unit. Salvage
depths were determined following a detailed evaluation of pH, electrical conductivity, saturation
percent, soil texture, Sodium Adsorption Ratio, calcium carbonate percent, and coarse fragment
percent.
The recommended topsoil salvage depth for each map unit is based on average of all depth
samples taken for the map unit.
Table 2.04.9-2: Criteria for Pre -Mine Soil Evaluations (Original Soil Sampling)
PARAMETER — UNITS
THRESHOLD LEVEL'
pH
<6.1, >7.8
Conductivity (mmhos/cm)
4.0
Saturation percentage (%)
>80%
<25%
Sodium adsorption ratio
>4
Calcium carbonate percentage
15%
Selenium (ppm)
>2 ppm
Particle size 4
All soil textures except: s, Is, sc, sic, c
Coarse fragments (%)
15%
'The threshold levels are to be used as a guide in evaluating the quality of a soil material for reclamation. An evaluation should
take into account the "total system". Interactive parameters may either nullify or verify the significance of a potential problem.
2The actual maximum acceptable salt level will depend on the plant species proposed in the revegetation plan and the potential
for upward salt movement.
3Specific level depends upon clay mineralogy, soil texture, and saturation percentage according to Dollhopf et al., 1983.
4The specific percentage of clay or sand allowed will depend upon clay mineralogy, organic matter content, consistence, soil lift,
spoil characteristics, and size of sand fraction.
5These values may vary depending upon the plant species proposed for revegetation in specific locations (e.g., a soil with a
high coarse fragment content throughout its profile may be completely salvaged if used for rangeland versus cropland
postmine land use).
January 2015 (TR -70) 2.04.9-8