PERMFILE130951

• Permit No: C1981022A
• IBM Index Class Name: Permit File
• Doc Date: 9/16/2005
• Section_Exhibit Name: 2.04 Environmental Resources
• Media Type: D
• Archive: Yes

• disturbance areas (west bench area) and that the undifferentiated surface and subsurface materials in
the ocher disturbance azeas generally meet revegetation suitability criteria and can be reclaimed with
the addition of approximately G-inches of suitable topsoil material. Recognizing that soil material
availability is a concern, OMI has committed to recover all reasonably available and recoverable soil
resources from new mine disturbance areas (up to a maximum depth of four feet) and to sample and
test replaced soils for suitability prior to revegetation.
Based on soil evaluations and analyses, the Absarokee-Work loam and Beenom-Absazokee association
are recoverable throughout their respective soil profiles except where constrained by the presence of
clay materials or topographic limitations. Similazly, the Totriorthents-Haplazgids complex is generally
recoverable throughout its profile except where constrained by depth vaziabi$ry, clay materials,
topographic limitations, or most significantly, surface rocks and boulders and high rock content. Of
the four soil types that have been or will potentially be disturbed, -the Tornorthents-Rock outaop,
sandstone complex, is the most limited relative to potential soil recovery and availability. Limitations
on recoverability of Toniorthents-Rock outcrop, sandstone complex soils include day content, depth
variability, high stone content, possible selenium concerns for the subsoils, and most significantly,
topographic limitations and operational constraints assodated with extensive exposures of rock
outaops and numerous lazge rocks and boulders on the surface.
Consistent with and as a reflection of limited soil development, soil sampling and analyses indicate
very little difference between surface and subsurface materials for the soil types evaluated. The only
potential material suitability constraints identified (based on Wyoming Department of Environmental
Quality Guideline No. 1 for Topsoil and Overburden in the absence of Colorado guidelines) were
boron (Samples HC-1, HC-2; BC-1, BC-2, BC-3, BC-4, ECS-I, ECS-2, and EC-1 through EC-9),
selenium (Samples EC-10B, EC-11E, and EC-11F), and clay (Samples BC-3, ECS-1, ECS-2, EC-1,
• EC-4, EC-5, EC-8, EC-9, EC-]OA through EC-]OF, EC-11A through EC-11F, EC-12A, and EC-
12B).
The elevated boron values aze for samples that were prepazed using acid digestion of the samples and
then analyzed. The resulting total boron concentrations indicated aze several orders of magnitude
higher than typical values for the normal analysis method, are not consistent with boron values for
other soil samples analyzed using the normal analysis method, and should not be considered as
representative of actual soil suitability relative to boron content.
The three samples having elevated selenium values were minimally above the suitability threshold for
selenium of 0.1 ppm (i.e. 0.18, 0.115, and 0,78) and represent only 7.5 percent of the 40 samples
analyzed. While these samples represent a potential concern that will be evaluated through sampling
of the replaced soil materials the concern does not appear to be significant based on the available
sampling data.
Clay texture appears to be a more prevalent concern based on the number of samples showing this
chazacterisdc for the sampled soils. It should be noted that for some of the earlier samples (1980 Pre-
Law Disturbance Sampling Program) the rexmral classification was based on visual chazacterization
rather than actual particle size analysis, however, clay texture does appeaz to be a limiting constraint
which may affect soil recovery and is taken into consideration in OMI's reclamation plans.
•)
IIWCRF 2.0491 Revised)une 2003