1991-03-20_REPORT - C1981008 (2)

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Soil Fertility. Replaced soil was sampled, tested, and evaluated for fertility to ensure optimum germination, seedling emergence, and root growth conditions. Two distinct types of soil were identified in the field while measuring soil thickness within the Pit 2 reclamation area. Soil at sites 8, 9, 12, and 13, transported from stockpile 10, consisted of grayish brown to brownish gray sandy loam while soil at the remaining ten sites, replaced from stockpiles 9 and 13 consisted of reddish brown sandy loam and sandy clay loam. Soil subsamples for fertility analysis were collected from the same sites used to measure soil thickness. The subsamples were composited into two samples according to soil type. The soil was placed in clean, labeled, canvas storage bags and was kept cool and dry to Limit chemical changes. The samples were shipped to Inter-Mountain Laboratories in Farmington, New Mexico for analysis. The soil analysis methods are listed in Table 2. Laboratory results for the two soil samples are presented in Table 3. Fertility levels considered adequate to obtain good plant establishment, site stability, floristic diversity, and moderate productivity are listed in Table 4. These fertility levels are recommended for native and improved range grasses. The soil in the Pit 2 reclamation area has a high to excellent fertility status for soil reaction, texture, nitrate, and ammonium. Phosphorus and organic matter levels are moderate to high. The laboratory data indicate no fertilizer supplements will be needed for successful revegetation. Soil Balance. Minimal soil handling activities have occurred since completion of the 1989 Annual Topsoil Balance Report (PCC, 1989). The following discussion describes the activities that took place during the 1990 field season and explains how the activities affected the soil balance for Nucla Mine. About 8.9 acre feet of soil from stockpile sites 9, 10, and 13 was replaced in the Pit 2 reclamation area. This compares closely with the 7.4 acre foot projection presented in the 1989 Annual Topsoil Balance Report (PCC, 1989). The soil reserve at stockpile sites 9 and 10 was completely exhausted. Approximately 6.1 acre feet of soil was removed from stockpile site 13. About 55.3 acre feet of soil remain at this stockpile site. Sufficient soil exists in stockpiles 2,3,8, and 13 to replace the required depths of soil specified on Exhibit 2, Postmine Soil Replacement Depths, presented with the 1989 Annual Topsoil Balance Report (PCC, 1989). 3