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 (b) Continued.
Rule 2.04.6
Revised 11/6/80
Chloride
Chloride values in the samples are relatively low, ranging from
0.10 to 70 ppm with a mean value of 16.48. Neither the Wyoming or
Montana Guidelines list any limits for chloride. The low concen-
trations of this constituent are not expected to cause any problems
with ground water quality or plant toxicity.

Acid-Base Potential
Sulfides present in overburden material have the potential of
lowering the pH of the ground water unless they are neutralized by
calcium carbonate, or lime. By comparison of sulfides with calcium
carbonate in the overburden, an estimate of the net acid-base
potential can be made. Such a comparison shows that only 7 of 53
samples had insufficient amounts of lime to offset the sulfides. A
total of 86.8% of the samples need no additional 11me and have a
significant excess of lime with respect to that amount needed for
neutralization. Of all samples, the mean value of lime needed is a
negative 8.79 tons per 1,000 tons overburden. The minimum value is
negative 32.52 and the maximum value is 17.85. Given the amount of
lime available, no problem is expected with respect to acidity.
It should be noted that three samples had insufficient amounts of
material to determine sulfate content. As shown on page 7 of Table
73a, these are hole nos. 028-79-16: 95-100'; 028-79-36: 30-68'
and 028-79-61: 15-75'. In the case of the first two of these, the
sulfate content was assumed to be 0.01%. Since the sulfide content
is computed by subtracting sulfate from total sulfur, the use of a
conservative estimate of sulfate yields a sulfide value that can be
considered "worst case". Since the sulfides are the sulfur form
which has the acid-producing potential, this conservative method
will not yield unrealistically low acid-potential values.
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