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~. t~Gr,FivF~? NOV 0 6 1995 Division of nnme~ ~,~ „ ,;~,;,,,, ,, DATE: October 31, 1995 TO: Barbara Pavlik ,^ J~fG~/{.GA FROM: Dan Mathews RE: Draft Refuse Area R vegetation Study Deserado Mine (C-81-018) I have reviewed the August, 1995 draft refuse area revegetation study report, and observed the test plots on my October 26, 1995 inspection at the Deserado Mine. My concerns and observations with respect to soils and vegetation aspects of the report are presented below. Vegetation Based on vegetation data included in the report and my site observations, I would concur with the operator's conclusion that soil cover depth does not appear to have influenced vegetation characteristics such as species composition, cover, production, woody plant density, or vigor. In the north facing test plots, the general trend is decreasing cover and production with increasing soil depth. A likely explanation for this observation is that the plots with the thickest soil cover are located at the east end of the study area, where they are most exposed to the drying effects of the prevailing wind. The 12" plot (N4) is located at the west end of the study area, where it is somewhat sheltered by a ridge immediately west of the refuse area. Reclaimed portions of the refuse area immediately adjacent to Plot N4, which presumably received the four foot cover thickness, appear to support a vegetation stand which, based on visual evaluation, is not distinguishable from the vegetation stand in plot N4. No readily apparent trend is discernible in the south facing test plots, however total production and cover values for the 12" plot (S4), equal or exceed the 48" plot (Sl) levels. The above observations which tend to downplay the influence of cover depth are tempered by the _f act that a ~ge~de~arlyrhy,Mpoorr,Yrstl+a~hd~+o~ an• o~bh'e~"'eT s.e a ~hokl~eR The bulk of the vegetation cover and production in 1995 was provided by two weedy annual