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will be implemented based on recommendations of the local NRCS or agricultural extension <br />office and may employ mechanical, chemical, or biological controls. OMI.LC will modify the <br />CDRMS permit as necessary to address any previously unspecified measures to be implemented. <br />As part of its Annual Reclamation Report (ARR) required under Rule 2.04.13, OMLLC will <br />summarize its weed control activities for the year. <br />2.8 DETERMINING REVEGETATION SUCCESS (RULES 2.05.4.2(E), 4.15.7) <br />Any revegetation success determination at the mine site is complicated by the following <br />factors; time of disturbance (pre- or post-SMCRA), surface ownership, multiple vegetation <br />communities, and post -mining land use. Within the mine site there are areas dating from the <br />initial disturbance date of 1901, there are four separate surface land owners (two private and <br />two public), three major vegetation communities (pinon-juniper, mountain shrubland, and <br />aspen/conifer woodland), and two approved post -mining land uses (undeveloped land and <br />industrial/commercial). <br />Table TR -A illustrates the mine site locations, age (pertinent to revegetation success), post - <br />mining land use, and applicable CDRMS rule (which determines revegetation success <br />criteria). <br />The following discussion will address each revegetation success variant. <br />2.8.1 REVEGETATION SUCCESS CRITERIA: PRE-SMCRA, UNDEVELOPED LAND <br />RECLAIMED AREAS (CATEGORY A) <br />CDRMS Rules 4.15.10(1) specifies the revegetation success criteria for areas previously <br />disturbed (pre-SMCRA) and not reclaimed to the current requirements (post-SMCRA). For <br />the undeveloped land post -mining land use at OMLLC, the applicable revegetation success <br />criterion is that the "minimum ground cover of living plants shall not be less than can be <br />supported by the best available topsoil or other suitable material in the reaffected areas, shall <br />not be less than the ground cover existing before redisturbance, and shall be adequate to <br />control erosion." <br />As these areas had no topsoil salvaged for use in reclamation, the material used will be best <br />available non-toxic, non-combustible material. These areas were not "re -affected" in the <br />definition of the Act and Rules, therefore the ground cover existing was largely non-existent <br />or annual weedy species, unsuitable in a reclamation scenario. The revegetation success <br />criteria for these areas would then be `ground cover adequate to control erosion'. <br />Absent site specific quantitative data, development of the criterion must rely on technical <br />standards and modelling to establish a ground cover value adequate to control erosion. In <br />the past, CDRMS has employed the Universal Soil Loss Equation (and subsequent <br />modifications) to evaluate the success of revegetation for Phase II bond release. <br />This equation employs five site specific environmental and management factors to calculate <br />the amount of potential soil loss per acre per year. By selecting a soil loss value applicable to <br />adjacent native areas, the equation can be rearranged to calculate a cover factor for <br />vegetation. This value can be converted into a ground cover of living plants, which, by <br />virtue of the acceptable level of soil loss selected for the calculations, should yield a ground <br />TR -77 H-8 Revised March 2019 <br />