PERMFILE116859

• Permit No: C1980006
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: PART 779 Environmental Resources
• Media Type: D
• Archive: No

•
Section 779.14(a) Continued. Rule 2.04.6
had values above the suspect level set forth in the Montana Guidelines of
1.0 ppm. Given the alkaline nature of the groundwater, no toxicity or
groundwater quality problems are expected with respect to cadmium.
Lead (Pb). A total of 54 Kerr samples and 50 BLM samples were analyzed
for lead. In the Kerr samples the DTPA lead values averaged 1.39 ppm
with a range from 1.60 to 24.76 ppm, while the BLM samples average 0.85
ppm with a range of 0.31 ppm to 1.58 ppm. Of these samples, only one (1)
had a lead value above the 20 ppm suspect level set forth in the Montana
Guidelines. On a volumetric basis only 0.61 percent of the overburden
exceeds the Montana suspect level. Since lead has been documented as a
contaminant of drilling grease, this excursion may be a result of
contamination. In any event, lead is not suspected of being a problem.
Further, according to Moran and Wentz (1974), lead is one of the most
• inert and least soluble metals. For these reasons, lead is not expected
to be a problem with respect to revegetation or groundwater.
Nickel (Ni). A total of 54 Kerr samples and 47 BLM samples were analyzed
for nickel. In the Kerr samples, the DTPA nickel values ranged from 0.480
to 8.24 ppm and had a mean value of 2.25 ppm. The BLM samples averaged
1.66 ppm and ranged from 0.9 ppm to 2.7 ppm. Montana has proposed a
suspect level of 1-5 ppm for nickel. A total of 85 or 84.2 percent of the
samples, as well as the mean value, are over the minimum suspect level of
1 ppm set forth in the Montana Guidelines.
Using the 5 ppm Montana upper suspect level only five (5) samples,
amounting to 0.61 percent of the overburden volume, could be considered
suspect. Barth et. al. (1981) recommends a DTPA standard at 20 ppm. For
this and several other reasons, nickel is not expected to be a problem.
First, it occurs in concentrations above the 1.0 ppm level throughout the
entire overburden sequence, so any selective spoil placement would be
ineffective. Second, nickel is relatively insoluble, according to Moran
and Mentz (1974), and should present no problem with respect to
groundwater leaching. Bingham et. al. (1979) report that, with respect
to soils, nickel uptake is lower at higher pH values. Overburden and
groundwater pH values in the permit area are high with a mean pN for the
779-21 a Revised-Apri1,1990