Laserfiche WebLink
of material with a range of 13.6 to 42.9 tons. These data dearly document <br />that not a single sample from the Southfield Mine refuse pile has the potential <br />to become acidic. The very low pH values associated with the oldest refuse <br />are not representative of the current refuse materials due to the increased <br />amount of waste rods present. Upon applying the add base potential criteria <br />recommended in the NMMMD Guidelines, the refuse materials are actually <br />superior to the soil materials as a plant growth medium. <br />Upon excluding the very low pH samples associated with the very old <br />refuse piles and the very high SAR values that are assocated with the <br />unweathered refuse the overall suitability value for the Southfield Mine refuse <br />material is 1.23 which is approximately 25 percent higher in overall quality <br />than is associated with the soil materials. This comparison dearly suggests <br />that the refuse materials are the "best available non-toxic' materials available <br />at this site. <br />CONCLUSIONS <br />The thickness of cover soil necessary for successful reclamation of the <br />Southfield Mine refuse materials is uRimately dependent on the quality of the <br />refuse materials that will be reclaimed. If it is assumed that these materials <br />are sodic, which is a questionable assumption because they lack all of the <br />characteristics of sodic spoil with the exception of elevated levels of sodium, <br />• it is possible to calculate the amount of soil cover necessary for their <br />reclamation. Barth (1984) presented a numeric formula for calculating the <br />amount of cover soil necessary for reclamation of sodic mine spoil in the <br />Northern Great Plains. His formula for sodic spoil is veld = 4.592 + 5.931 x - <br />0.0505x2 + 0.0001412x3, where yield is in grams per square meter and x is <br />soil depth in cm. This numeric formula appears to apply very well to the <br />Southfield Mine refuse materials. For example, to date all of the reclamation <br />done on the refuse pile has averaged four feet of cover. Using the 1987 <br />reclamation monitoring data collected from the previous reclamation on the <br />Southfield Mine refuse it is possible to somewhat compare results predicted <br />by Barth (1984) with actual on site data. Reapplying four field of cover yields <br />a theoretical yield value of 233.1 grams of air dry forage per square meter <br />which compares to an actual yield obtained from sampling of 229.3 grams <br />per square meter. The extreme closeness in the theoretical and actual yields <br />suggest that the formula of Barth (1984) can be used with a high degree of <br />accuracy for these materials. <br />Upon applying the previously collected yield data for the Southfield Mine <br />refuse pile area, ft is possible to calculate the exact amount of respread <br />topsoil necessary for final reclamation of the Southfield Mine refuse materials. <br />Using the production levels presented in the original Dorchester Coal <br />Company permit, wherein 1980 production values of 58.65 grams of biomass <br />were reported for the refuse area, reapplication of 10 cm (4 inches) of topsoil <br />would yield a total biomass of 58.99 grams per square meter. Sampling in <br />. 1987 from the refuse reference area yielded 74.08 grams of biomass per <br />square meter. Reapplication of 15 cm (6 inches) of topsoil would produce <br />82.67 grams per square meter. Assuming that the site was in excellent range <br />condition using the SCS Range Site information and was producing the <br />maximum amount of forage possible for this site, 1500 pounds (168.1 grams/ <br />41 <br />