2018-06-05_PERMIT FILE - C1981019A (7)

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RULE 4 PERFORMANCE STANDARDS For certain statistical demonstrations of woody plant density, documentation of sampling adequacy is often problematic, hence Rule 4.15.11 (3) may be used in lieu of Rule 4.15.11 (2). Rule 4.15.11 (3) (a) is a reverse -null approach based on the median and requires a minimum of 30 samples. Rule 4.15.11 (3) (b) allows direct comparison with standards if a statistically adequate sample cannot be demonstrated in accordance with Rule 4.15.11 (2) (a), however, a minimum of 75 samples with a minimum quadrat size of 100 mZ is required (equivalent to total enumeration of 1.85 acres). Rule 4.15.11 (3) (c) is a standard -null approach based on determination of a "running mean" and a minimum of 40 samples is required. Success Evaluation To summarize, success evaluations involve either a direct or a statistical t-test comparison of appropriate parameters for each variable of interest (cover, production, diversity, or woody plant density). For monitoring efforts, comparisons shall be made directly with either the reference area parameters or the permitted standards to facilitate a determination of the progress of revegetation. In the case of ground cover and production, comparisons shall be made against reference area data of the same year. Diversity and woody plant density variables shall be compared against the standards defined above. For bond release efforts, direct comparisons are made when the revegetated area mean value for a given variable is greater than either 90% of the standard or the reference area mean assuming that a statistically adequate sample has been collected. If a statistically adequate sample cannot be obtained, a "reverse - null" hypothesis test may be employed as detailed in C.R.S. Rule 4.15.11 (2) (c). If an adequate sample is obtained for a particular variable, but the mean is less than 90% of the reference area mean or standard, a "standard -null" hypothesis t-test may be employed as detailed in C.R.S. Rule 4.15.11 (2) (b). For the typically problematic variable of woody plant density, Colorado has implemented three alternate adequacy / success evaluation methods under C.R.S. Rule 4.15.11 (3) that may be utilized in lieu of those detailed under 4.15.11 (2). Until experience dictates which procedure is best (because these are relatively new metrics to the science), it would be prudent to collect a minimum of 75 belt transects (at least 100 mz in size) as indicated in 4.15.11 (3)(b)(i). These data can then be used for the various analyses / comparisons. 4.16 Postmining Land Use 4.16.1 General Implementation of the detailed reclamation plan as presented in Section 2.05.5 will result in a landscape and vegetative cover that is equal to or better than the premining condition for rangeland use that currently exists in the area. 4.16.2 Determining Use of Land The premining land uses for the mine plan and adjacent areas are shown on the Land Use Map (Map 17). The narrative describing the land use of the permit area is presented under Section 2.04.3. The proposed postmining land use will involve the restoration of the premining land use of rangeland, as described in Section 2.05.5. 4.16.3 Prior to Release of Lands from the Permit Area in Accordance with 3.03.1 (2) (c) The land use of rangeland will be restored in a timely manner as outlined in Section 2.05.4. Implementation of the timetables contained therein will assure a contemporaneous reclamation program. No alternative land uses will be implemented in the reclamation plan set forth under Section 2.05.4. Rule 4 Performance Standards 4-72 Revision Date: 1/31/18 Revision No.: TRA 19