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

• study period. Using the data in Fimbel (1982) in can be determined that pH,
EC, Zn, Fe and percent sand all significantly declined over time, while organic
matter and percent clay significantly increased. The average nitrate nitrogen
content increased from a mean of 11.25 ppm to 29.17 ppm but the means
were not significant. These soils data document that the refuse materials
were undergoing obvious weathering as evidenced by the number of physical
and chemical changes. Most importantly all of the changes in the properties
of the refuse materials were favorable with respect to plant growth and
suggest that with proper regrading and reclamation techniques the sodicity
problems of coal refuse were largely self correcting.
Aside from the graduate research conducted by Abbott (1981) and Fimbel
(1982) researchers at CSU, conducted several additional studies on these
refuse materials that were not reported in the graduate theses. Redente and
Abbott (1980) reported that gypsum °depresses plant vigor in many
treatments and hinders revegetation.' Plant growth, infiltration and soil
temperature were reported to be more favorable on 3:1 slopes as compared
to 1.5:1 slopes. The refuse materials were found to be very low in plant
available phosphorus, but these researchers concluded that the lower nutrient
levels in the refuse materials were probably not responsible for the observed
vegetation growth and that the refuse materials would not need 'any
amendments of fertilizer now or in the future.' Application of 15 cm of topsoil
to the refuse was determined after four years to produce only a "mediocre
• plant pertormance' due to the dominance of annual weeds on this medium.
On slopes of 3:1 or less the technique of fertilizer and mulch were
recommended to aid in promoting plant establishment. Nitrogen application
rates in excess of 66 kg/ha were not justified, and additional investigation of
topsoil was recommended.
Investigations by the U.S. Bureau of Mines (Backer et. al. 1977) on coal
refuse piles from the Raton Coal field in Northeastern New Mexico and the
Wasatch Plateau coal field in Utah revealed that the characteristics of western
coal refuse materials as a whole were significantly different that those found
in the eastern coal fields. They reported that the physical properties of
western refuse were much coarser, had higher permeabil'~ties, lower
saturation levels, were more stable, and had higher densities. Chemically, the
western refuse was reported to contain less alumina and much higher levels
of calcium oxide, both properties which significantly render western coal
refuse materials less likely to become acidic.
To date, the most comprehensive attempt to characterize the physical and
chemical properties of western coal refuse materials appears to be the study
of White et. al. (1982), wherein 15 refuse disposal sites in western Colorado
and eastern Utah were evaluated. The study concluded that compared to the
normal agronomic standards, these materials had low levels of nitrogen and
phosphorus and salts. Aging appeared to resuR in lower pH values, but only
two of fifty samples taken had pH values below 5. Statistical analyses by
these authors documented that pH and SO4 were significantly correlated with
. sample age. Decreases in pH and increases in SO4 were reported. They
reported that the pH of new refuse (mean 8.65) was significantly more basic
than old refuse (mean 7.56, t=3.27, p < 0.01). Aging was reported to
significantly increase the EC of the refuse materials. Old refuse was reported
to have a greater mean EC (mean 1.23 mmhos/cm) than the new refuse
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