PERMFILE117745

• Permit No: C1982055
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: ADDENDUM A SUITABILITY EVALAUATION OF THE RATON CREEK MINE REFUSE COVER MATERIALS
• Media Type: D
• Archive: No

• material was taken from waste materials by the conveyor at the portal. A Red
Dog sample was collected approximately 15 feet south of the existing diesel
storage tank. Bench material from the white Raton Sandstone was taken from
the area to the southeast of the portal near the sump. Two Bench Fill
samples were taken to the south of the sump on the exposed bench pads. The
analytical methods used in the laboratory analysis and the 1988 sampling
results are presented in Exhibit 1, Results of Laboratory Analyses.
DATA INTERPRETATION
Due to the absence of published Colorado suitability guidelines, the
overburden data were compared using the suitability criteria found in the
1984 Wyoming Topsoil and Overburden Guideline (Wyoming DEQ 1984).
Specifically, the suitability rankings found in Table I-2, Criteria to
Establish Suitability of Topsoil (or Topsoil Substitutes), and Table I-4,
Criteria to Establish Overburden Suitability were used. The New Mexico
Mining and Minerals Division's 1987 Overburden and Soils Guidelines were also
consulted in this evaluation (New Mexico MMD 1987). In this reference, the
ratings proposed in Table C, Soil and Soil Substitute Suitability Ratings,
and Table D, Potential Root Zone Overburden Suitability Ratings, were
consulted. Given the CMLRD's past reliance on the Wyoming Guidelines,
preference will be given to this document. In the following evaluation each
sample parameter suggested in the Colorado Guidelines will be discussed using
the appropriate suitability ranking found in these two references to
determine the suitability of these materials as potential cover soil media.
• For the parameters in the Colorado Guidelines that do not have suitability
criteria listed in either the Wyoming or New Mexico Guidelines, the technical
publications of Schafer (1979) and Sutton et. al. (1981) were consulted.
Since these sources list slightly different suspect levels, the lowest
suspect level for a given parameter was used.
SAMPLING RESULTS
Soil Reaction (pH). The Wyoming Guidelines define topsoil substitute
materials as having a "suitable" ranking when the pH values range between 5.5
and 8.5. The pH values for the Raton Creek Mine overburden and bench
materials ranged from 5.6 to 7.8 with a weighted mean pN value of 7.05,
meaning that all of these 24 observations fall within the "suitable" range
with respect to soil reaction. This means that no potential problems appear
to be associated with these materials with respect to their soil reaction.
Electrical Conductivity (EC). The Wyoming Guidelines define topsoil
substitute materials as having a "suitable" ranking when all of the EC values
are less than 8 mmhos/cm. The EC values for the Raton Creek Mine overburden
and bench materials range from 0.32 to 4.65 with a weighted mean value of
0.74 mmhos/cm. All of the 24 observations were found to correspond to the
"suitable" category. One observation had a value exceeding 4 mmhos/cm. This
bench sample material was white Raton Sandstone material that had been
deposited at the time the mine closed in 1984. Elevated salinity levels were
not expected for this material due to its sandy texture, and it is believed
that because of exposure to water and salts while inside the mine that these
salinity values are somewhat elevated. These conditions are indicative of
• contaminated conditions. Due to the mixing that will occur when these bench
materials are used for reclamation and the salt tolerance of native plants,
this one excursion above the suspect level should not pose any concerns
regarding ultimate reclamation success. On a volumetric basis all of these
materials would fall within the "suitable" category once the .mixing