2019-11-22_REVISION - C1981019 (2)

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RULE 4 PERFORMANCE STANDARDS Currently the reference areas are located in an area where grazing can be managed in accordance with the approved postmining land use. Comparisons of weighted averages between reference areas and revegetated areas under Subsection 4.15.7(4)(b)and Subsection 4.15.11 may be utilized to determine revegetation success. Similar methodologies and statistical tests used to compare premine and reference areas will be used to compare reference areas and revegetated areas. For weighted comparisons of original permit area revegetation (grazinglands), reclaimed area data will be compared against 55% Mountain Shrub Reference Area and 45% Sagebrush Reference Area data. However, some comparisons may be made directly against a single reference area (e.g., Sagebrush Reference Area). In this regard, any sagebrush steppe community that evolves in the reclaimed area will be directly compared against the 1981 sagebrush reference area. For weighted comparisons of South Taylor revegetation, reclaimed area data will be compared against 52% of the 1980 Mountain Shrub Reference Area, 25%of the 1981 Sagebrush Reference Area, and 23% of the 2005 Collom Aspen Reference Area. For demonstration of revegetation success,vegetation cover,herbaceous production,and in certain circumstances woody plant density will be sampled to statistical adequacy(where necessary), and compared to the approved standard or reference area mean. The Division has completed a comprehensive bond release guideline (1995) that provides a good overview of recommended sampling approaches, statistical adequacy formulas and statistical tests. Furthermore, new regulations promulgated 9/14/05 under Section 4.15.11 detail new allowable approaches for vegetation sampling and testing. Colowyo will utilize procedures recommended in the new regulations,guideline,or other procedures that are as effective as the Division's recommendations. Before Colowyo begins a vegetation sampling program for bond release, the Division will be consulted to confirm sampling approaches and statistical testing. A base level or initial protocol is detailed under Section 4.15.11 below. As indicated in Rule 4.15.7 (5) the 10-year liability period will begin following the last year of augmented seeding, fertilization, irrigation, or related revegetation work. To facilitate bond release, revegetation success criteria must be met for two of the last four years of the liability period excepting that sampling for final success determination cannot occur prior to year 9 of this period. The liability period will be re-initiated for augmentation work excepting work associated with normal management activities as defined under Rule 4.15.7(5)(a-g). This allows the liability period to remain unchanged for such revegetation metrics as "interseeding" (4.15.7 (5)(g)) of additional grasses and forbs into a stand targeting shrubs to increase cover values of these life forms. To summarize the use of reference areas in this testing process, the following will occur. There are three reference areas that will be utilized for testing against reclamation success. These reference areas are: 1980 Mountain Shrub reference area, 1981 Sagebrush reference area,and 2005 Collom Aspen reference area. All lands reclaimed prior to 2008 and grazinglands (grasslands) reclaimed post-2008 on the original permit, East Pit, West Pit, and South Taylor areas, shall be compared to weighted parameters from the 1980 Mountain Shrub reference area(55%weight)and the 1981 Sagebrush reference area(45% weight) in accordance with 4.15.7(4)(b). All post-2008 Rule 4 Performance Standards 4-63 Revision Date: 11/18/19 Revision No.: MR-211