PERMFILE51657

• Permit No: C1981008A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: NH1 TAB 6 GEOLOGIC INFORMATION
• Media Type: D
• Archive: Yes

6-9. Exceptions include the unsuitable pH and or acid base potential
values for holes 873E (Units 2 ar~d 4), 874E (Units 2, 4 and 5); 875E
(Units 2, 4 and 5) and 876E (Units 4 and 5); the unsuitable saturation
percentage at hole 873E (Unit 2) and the unsuitable iron concentrations
at hole 863E (Units 2, 4 and 5). These unsuitable parameters are
briefly mentioned in the Mitigative Measures section of this tab and
evaluated in Tab 21, Minesoil Reconstruction.
Table 6-15 statistically summarizes the physiochemical data gathered
during the Phase II sampling program by determining the mean of all the
individual core hole weighted means for each lithologic unit. Again,
the majority of mean values all fall within an acceptable range as
outlined by the assessment criteria listed in Table 4. Exceptions
include pH values of 4.0, 3.9, and 4.3 recorded for Units 2, 3, and 4,
respectively and the acid base potential values of -11.9 and -5.6
recorded for Units 2 and 4, respectively. These parameters are
briefly mentioned in the Mitigative Measures section of this tab and
further evaluated in Tab 21, Minesoil Reconstruction.
The following parameters, analyzed at site 873E only, are suitable
across all lithologic units. SAR values ranged from 0.3 to 6.5. The
highest values were associated with the upper Dakota Coal seam and
adjacent very dark gray carbonaceous shale (Unit 2) while the lowest
levels occurred in the light gray sandstone and shale underburden (Unit
5). Calcium is the dominant cation in lithologic Units 1, 3, 4 and 5
while sodium is dominant in Unit 2.
Zinc and nickel concentrations ranged from 0.2 to 12.7 ppm across all
lithologic units. Values were highest in the underburden and upper
Dakota Coal seam and surrounding very dark gray shale and lowest in the
overburden. These zinc and nickel concentrations are typical and
nontoxic for soil and overburden material (Barth et al., 1977).
Molybdenum values were consistently less than 0.4 ppm across all
lithologic units. These concentrations of anion extractable molybdenum
are suitable for normal plant growth (Barth et al., 1977). The
aforementioned parameters (Na, Ca, Mg, SAR, Ni, Zn, Mo) were all at
6-50 Revised 04/11/88