2020-07-09_REVISION - C1981028 (15)

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DETERMINING FINAL REVEGETATION SUCCESS CEC has elected to use standards developed from vegetation monitoring events between 1994 and 2005 at the Osgood Sand Reference Area, for the evaluation of revegetation success at the Keenesburg Mine site. With the approval of TR-37 (611512006), sampling of the Osgood Reference Area was discontinued. Beginning with the 2006 sampling event, total vegetation cover and total herbaceous production are evaluated through values calculated from predictive equations based on growing season precipitation at the mine. For the parameter of species composition, a quantitative success standard based on relative cover was developed by the Colorado Division of Reclamation, Mining and Safety, and CEC. Since there is no requirement for the replanting of woody plants, there are no woody plant density success criteria. In 2012, CEC revised the predictive equations for establishing final revegetation success standards for vegetation cover and herbaceous production. The revised equations removed plant species identified as ineligible by CDRMS, and provided an equitable basis for comparison of the derived standards for current and future revegetation at the mine. These revised equations (and standards)were approved in TR-43. In 2020, CEC revised the species composition standard to remove the species seasonality requirement for current and future revegetation at the mine. This revised standard was approved in TR-47. Sampling Methods The reclaimed area(s)will be sampled to allow a determination of sample adequacy. The reclaimed area may be treated as a single type or divided into parcels, based on seeding date or other logical criteria. Sample locations within all reclaimed parcels will be randomly selected using randomly generated grid coordinates overlain on a map of the mine. Transect and quadrat locations are randomly selected prior to the commencement of field work. The reclaimed area(s)to be sampled are divided into a grid on the mine map. Horizontal and vertical axes are assigned a unique alphabetic or numeric character. Characters are then randomly generated, and sample points established based on their unique [x,y] Cartesian coordinates. Extra sample points are generated and plotted to be used if a given location is not available for sampling (e.g., the sample point falls on an existing road or other structure). Total vegetation cover. Vegetation cover transects will be randomly located within the reclaimed areas. Transects will be of a length consistent with Colorado Division of Reclamation, Mining and Safety regulations. At this time, quadrants of 25-50 meters in length are proposed for the reclaimed areas at the mine. A total of fifty points will be collected per transect,using point transect methods. Each transect will serve as a sample unit. Points will be collected using a stationary optical sighting device to maximize reproducibility and precision. In multiple layers of vegetation, first hits are recorded for total vegetation cover,while subsequent "hits" will be used to calculate relative vegetation species cover. Vegetation cover data will be collected from the appropriate reclaimed area(s). For bond release, sufficient numbers of samples will be collected to reach sample adequacy. 116 7/2020