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- 14 - 10.6 million cubic yards of extra material from Pit 3, nor 1.2 million cubic yards of excess spoil from the 720 pit. However, Kerr may be able to make a case for establishment of a small excess overburden stockpile based on calculations presented in Section 4.14.4, page 4.14.8. Please modify the permit revision application accordingly. 57. Please specify the thickness of horizontal lifts used in construction of excess overburden piles per 4.09.1(7). Appendix A a. E. 1. Smith's 1966 Ph.D. dissertation is relied on heavily to support the stated views. It is stated on page 4.06-6 that "Smith reported that the big sagebrush he sampled was all mountain big sagebrush," yet Smith's results are used by KCC to draw conclusions about other sagebrush types. The Division believes that any conclusions from Smith's 1966 study that are extrapolated to other types of sagebrush may not be valid. b. KCC baseline data shows that Wyoming big sagebrush only grows on 28.3 percent of the area to be disturbed. It is therefore unclear why KCC wants to reestablish this shrub on all areas to be disturbed. It is, however, clear that the topsoil redistribution and reveaetation plans may not meet all the requirements of Rules 4.06 and 4.15. This is because the proposed plan does not commit to salvaging all topsoil and states that a plant community which would provide less cover and production would better serve the end land use. Such a plant community, however, would probably not provide the same protection of the topsoil resource from wind and water erosion as the native plant community did prior to disturbance. c. Biondini, et al. (1984) is stated as reporting that, "five years after seeding, the composition of planted and volunteer shrubs on the 30 cm topsoil depth averaged 138 compared to 5'L for the 60 cm topsoil depth." This study used several introduced and native shrubs in the seed mixtures, none of which were sagebrush. Furthermore, only composition of these plots is cited. The Division must consider vegetative composition, cover, and production when determining whether a reveaetated area will meet the requirements of Rule 4.15. In studies on the same plots by Redente and Cook (1984), shrub production was directly, positively, and significantly correlated to topsoil thickness over retorted oil shale. Another paper describing a different aspect of this same study by Biondini and Redente (1981) is cited (but not included in the KCC bibliography) as stating that species diversity is negatively correlated to topsoil thickness. Also, it is stated that the authors concluded that applied fertilizer amount is negatively correlated to species diversity. While this appears to be the case, the authors also pointed out that low production, high