GENERAL45889 - Laserfiche WebLink

Home Browse Search

.. • • III IIIIIIIIIIIIIIII 999 United States Department of the Interior ' OFFICE OF SURFACE MINING Reclamation and Enforcement BROOKS TOWERS 1020 lSTH STREET DENVER, COLORADO 80202 ~:~'`~~~/E® June 25, 1982 JUN 2° 1982 MINED LAND RECLAmATION Sandi Emrich Colo. Dept. of Natural Reso~rce< Colorado Department of Natural Resources Mine Land Reclamation Division 1313 Sherman St., Rm 423 Denver, Colorado 80203 Dear Sandit As per our phone conversation of June 22, 1982, I have summarized the concerns that I have with the Mt. Gunnison vegetation stipulation response regarding the proposed diversity standard. Anaconda Minerals is proposing the use of a similarity index to assess the attainment of acceptably diverse post-mine vegetation. In general, this proposal appears to be workable. However, many specific details still need to be resolved before the approach can be accepted. The use of a similarity index based upon growth forms assumes that the structure of the post-mine vegetation communities will be directly comparable to that of the reference area communities. Although this is potentially true in Mt. Gunnison's case, Anaconda has not stated specifically that the similarity index would be used to directly compare the dry meadow reference area with the rangeland interspaces and the mountain shrub reference area with the shrub clusters at the time of bond release testing. This needs to be resolved. Anaconda leaves open the exact choice of growth forms to be used in applying the similarity index. The list that is supplied in their proposal is acceptable, but should be supplemented by two additional growth forms, annual and perennial weed species. This should enhance our ability to evaluate the company's attainment of the post-mine land use objectives. Anaconda will need to include weed species in their cover sampling estimates, assuming cover is used for the similarity index values, even though MLRD vegetation policy does not at present generally require this. The company's cover sampling procedures would therefore need to be modified to reflect this change in future sampling. It may also be appropriate to further refine the perennial grass growth form into warm and cool season perennial grasses and to delete the tree growth forms listed.