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pH value of 5.2. Two small areas within sample plot #4472 (<2 acres) of oxidized coal fines <br />• and carbonaceous shales were identified and sampled in A pit. These areas were on a spoil <br />outslope and had not mixed well with the surrounding spoils. Laboratory analysis of these <br />spoils revealed the pH value fell outside the suitability range. Although isolated, past sam- <br />ples of similar colored and textured spoils have fallen within the suitability range for all spoil <br />parameters. <br />Upon receipt of the analytical data Trapper initiated remedial actions to identify the prob- <br />lem. The lab re-ran pH tests on the remaining sample. The results were similar so it wasn't <br />considered laboratory error. Trapper resampled the suspect area in January, 1991, and <br />submitted a second sample for analysis. The resultant value was an acceptable pH value of <br />6.2. <br />A pH value of 5.2, although below the approved pH suitability range of 5.5-8.8, isn't prob- <br />lematic. The areas involved are very small and localized. A pH value of 5.0 is still consid- <br />ered moderately acidic, within the common pH range for mineral soils (humid regions), and <br />within the suitability classification for plant gowth. <br />Literature indicates that acid producing pyritic or marcasitic overburden is rare in the arid <br />West. However, areas with higher organic matter (oxidized coal) at the same percentage of <br />base saturation will tend to be more acidic than normal soils. Due to the high calcium car- <br />• bonate (CaCO3) content of Trapper spoil and topsoil, an immediate neutralization of the <br />more acidic spoils is likely. The 6.2 retested pH value in the same area is testimonial to the <br />fact that the acidic spoils are being neutralized. <br />Trapper will visually monitor the vegetative response in this localized area (<2 ac) to <br />determine any detrimental effects. <br />Collation of the spoil analyses (1985-1989) presented in Appendix W (1989) showed all <br />parameters within the suitability ranges (Table 4.2 and 4.3). Table 4.3 compared spoil data <br />results to replaced topsoil (19$5-1990) parameters. <br /> <br />