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Mr. Brock Bowles <br />November 12, 2015 <br />Page 3 <br />"Acid Base Potential" to "Neutralization Potential Ratio" to clarify exactly what was being <br />assessed by the Acid -Base Accounting process. <br />Another clarification issue was evident with the "Particle Size (Texture)" parameter. This <br />parameter, with a stated value of 20% is unclear, and needs to be reworded to "Course Fragment <br />Content %" to provide clarity. Since this is a subsoil material, rock content could be significantly <br />higher than the current threshold without any detriment to reclamation success, and in fact might <br />increase success with slightly higher rock contents, as it promotes more desirable soil -water <br />mechanics. <br />The "Saturation Percent" parameter should be removed. This proper terminology for this soil <br />characteristic is Base Saturation Percent, and it is more applicable to intensively managed and <br />high productivity cropping systems where significant amounts of nutrients are being utilized from <br />the soil each year and removed from the system, needing replacement by fertilizers. <br />Additionally, even agronomists disagree as to where the "optimum" range of base saturation lies. <br />One school of thought is that the soil should contain a specific ratio of saturations for each of the <br />major cation nutrients (as plant uptake of nutrients is non-selective and occurs via mass flow of <br />the bulk soil solution), while the other argument suggests a wide range is acceptable, and <br />appropriate values should be derived based upon plant species, intended use of plants, the nature <br />of the soil (CEC, pH, surface area, clay type, etc.), and a variety of other things. There is no <br />benefit to this parameter relative to reclamation success, as soil -water issues (hydraulic behavior, <br />sodium, and salts) far outweigh fertility issues. Additionally, if anything was overly <br />disproportionate, it would be apparent in the results of the EC and SAR tests. <br />The "Electrical Conductivity" parameter is highly variable depending upon texture, temperature, <br />and the procedure used to measure it, while the importance of the results is dependent upon what <br />plant species you are trying to grow, and Post Mining Land Use and land management. Since the <br />seed mixes contain adapted native and species and this is a subsoil material, a threshold value of <br />< 6 is appropriate. If Bench 1 materials have higher SAR's, higher EC material can be used to <br />counter the negative effects of sodium and achieve more balanced soil chemistry. <br />The "Calcium Carbonate Percentage" parameter threshold value was too high, and needed to be <br />lowered to ensure reclamation success. Since the density of even pure calcium carbonate is <br />approximately the same as the soil particles, a pre -disturbance 40% carbonate material (as <br />suggested) would equate to a soil with about 0-10% pore space, having a significant negative <br />effect on soil water and chemistry. As with SAR and EC, these carbonates are mobile in the soil <br />water, and depending on the soil and climate, there is potential in and systems for carbonates to <br />start migrating up toward the surface once those pedogenic carbonates are disturbed and the <br />surface area of the carbonates increases several orders of magnitude. In unirrigated or poorly <br />drained systems, these carbonates can clog pore space and limit the infiltration depth and total <br />water holding capacity, which is undesirable in and systems. Since Bench 1 material is being <br />used as subsoil, a 20% threshold value is recommended. <br />AN EQUAL OPPORTUNITY /AFFIRMATIVE ACTION EMPLOYER <br />A Touchstone Energy Cooperative <br />