PERMFILE55696

• Permit No: C1981014
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: EXHIBIT 09 COMPARISON OF REFUSE AND SOIL SUITABILITIES
• Media Type: D
• Archive: No

• with each corresponding decrease in pH there is a corresponding decrease
in the SAR. This decrease is associated with progressive increases in the
amount of calaum that are being liberated by the acid breaking down the
unweathered overburden materials. These data also provide a very reliable
means of determining whether or not pyritic or organic sulfur is being
oxidized. Decreases in the relative concentration of these sulfur forms with
corresponding increases in the concentration of sulfate sulfur over time
means that oxidization is occurring. Conversely, if it can be documented that
the relative concentrations of these elements do not change over time, then
it can be deduced that the pyrite and organic sufur forms are not reactive.
The potential acidfication of overburden core materials from the western
states was recently summarized by Fisher and Munshower (1984). Unlike the
previous studies ated above that represent spoil that has actually acidified
under field conditions, their data rely largely on the probable occurrence of
acidfication based upon the acid base accounting methods, which are prone
to considerable error. However, data are presented from regraded mine
spoils showing that pH values of 4.5 are possible within a short period of time
following regrading.
Comparatively less research as been conducted on coal refuse materials
in the western states than has been conducted on mine spoil. This disparity
is largely a function of its more limited distribution. White et. al. (1982)
conducted what appears to be the largest characterization effort to date. Of
• frfteen mines they evaluated in western Colorado and eastern Utah a total of
50 pH values revealed that 45 samples were either neutral or alkaline with
respect to soil acidity. Using the SCS suitability criteria for suitability of soils
for reclamation (USDA-SCS 1983), 48 of the 50 samples possess a "good"
suitability with respect to acidity. The early work of Berg (1971) working at
a site near Trinidad, Colorado clearly suggests that the coal refuse materials
in this area could not be considered to be acid forming since the pH values
ranged from 6.6 to 7.1. The extensive research conducted by CSU at the
New Elk Mine fail to confirm that these refuse materials could be considered
to be acid forming since all of the pH values were above 7.0 on 15 to 20 year
old refuse. According to the SCS suitability criteria all of these materials
would rank 'good' with respect to soil reaction.
Due to relatively limited occurrence, the microbiological processes
associated with acidfication of western mine spoils have not been studied to
the detail that they have in the east. Most of the research in this area has
been conducted in Montana and adjacent parts of Wyoming. Olson and
McFeters (1978) studied the microbial relations of three surface coal mines
in this area. They determined that Thiobacillus ferrooxidans, the bacteria
responsible for the acid mine drainage problems in the east was widespread.
It was detected in surprisingly high numbers in groundwaters draining the
mined areas as well as in undisturbed welts. However, the problems
associated with aadification were very localized and any acidity produced
was quickly neutralized by the high bicarbonate levels in the groundwaters
• and carbonate levels in the spoils. The high sulfate concentrations found in
the waters draining the mined areas was attributed to the oxidization of
sulfuritic materials found in association with the coal bearing strata.
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