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III IIIIIIIIIIIIIIII 999 GREG LEWICKI AND ASSOCIATES February 12, 1992 Dan Mathews Mined Land Reclamation Division 1313 Sherman Street 2nd Floor Denver, Colorado 80202 ~~.- E618 1992 Mind Land t645 Court Place Suite 309 Denver, Colorado 80202 (303629-9335 Re: Data for proposed veget- ation standard at Trinidad Basin Mine Dear Dan: Enclosed is information that I have been able to gather in order to propose a vegetation standard at the Trinidad Basin Mine. The original pre-mine community was pinon-juniper and the post-mining community is rangeland which will be predominately comprised of grasses. I was able to get the local SCS office in Trinidad to assess the actual site. They then compared the site to the range site that most accurately represents the potential of the current site. Historical cover and productivity for this range site was then used by the SCS in suggesting standards for the reclaimed area. This information is enclosed. The SCS suggested a basal cover of 10% and a productivity of 300 lbs per acre. This will be converted to an aerial cover for purposes of the mine revegetation standard. I have also enclosed a paper by Wayne Erickson where SCS range site descriptions were used to determine revegetation standards at the Mckinley Mine in New Mexico. OSM accepted the methodology. This is very interesting because not only was the SCS range data used to avoid reference areas, it also avoided the baseline vegetation studies. In our case, we are simply asking that the SCS range data, existing soils and pre-mine vegetation data be used to establish a revegetation standard. Vegetation analysis of the reclaimed area and the pinon-juniper community was done in the summer of 1991 by Matt Hayes. The work on the pinon-juniper community was not sampled to adequacy. Regardless, this information is also enclosed. Excerpts from the original vegetation baseline study in the pinon juniper community are also enclosed. The two are in reasonable agreement.