2020-06-25_REVISION - C1981019 (6)

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RULE 2 PERMITS "On the basis of a September 18, 1981 field reconnaissance by Colowyo personnel together with Dave Craig and Brian Munson of the CMLRD staff, it was agreed that the SCS classification of Taylor Creek as an area of stratified alluvium was and is erroneous particularly as geomorphic criteria required to describe an AVF are absent. As a consequence, the designation of the Taylor Creek Drainage as quaternary alluvium on Map lOB, Regional Hydrology has been deleted. This area should be mapped as colluvium. "Other examination of the area on September 18, 1981 further confirmed a colluvial classification, in that some unsuccessful irrigation in the area is presumed to have occurred, and such irrigation was practiced on the colluvial slopes adjacent to the bottom of the drainage. No irrigation ditches, however, are extant, and it is apparent that no subirrigation occurs in the area. "Additionally, insufficient water flows in the Taylor drainage to sustain any flood irrigation. Irrigation apparently began from a ditch known as the Mary C. ditch in 1913 on an undetermined acreage, but was certainly less than 25 acres. The state Division of Water Resources records date back to 1960, and they have no record that this ditch has been used since that time. Years ago small isolated areas such as this could be irrigated economically, and were important to 160 acre size homesteads. "However, in recent years with larger farms and ranches, larger equipment, and increased labor costs, small isolated areas such as this are seldom irrigated. This is especially the case when the water source is from an ephemeral drainage such as Taylor Creek, and runoff is mostly a function of snow melt and large precipitation events, and varies largely from year to year. "The revised Map lOB will be submitted when all of the map revisions have been completed. Map 10 will also be revised to show that the area of quaternary alluvium extends to the confluence of Taylor and Wilson Creeks from the north. The labeling of the gauging stations at the confluence of Taylor and Wilson Creeks will also be corrected on the revised Map 1 OB". In order to verify the predicted effects of mining activities on groundwater and surface water, Stipulation 41 of the initial Permit required Colowyo to submit a comprehensive water monitoring plan. For further details regarding this plan, refer to Section 4.05.13, Surface and Groundwater Monitoring. Refer to the 1983 - 1989 Annual Reclamation Reports for further details as to the data collected. 2.06.9 Angering and Highwall Mining In the South Taylor Pit,highwall mining has successfully occurred on the E seam in the northwestern area of the West Taylor Fill and the northeastern extent of the box cut. Please see Map 23A for these locations. Currently, Colowyo is proposing to highwall mine the G7/G8, E, and D2 seams on the low wall and end wall of the South Taylor Pit(see Map 23A). The planned highwall mining sequencing will begin with the G7/G8 seam, and once mining is completed the pit will be backfilled to the E seam. Colowyo plans to highwall mine the E seam then backfill to up to the next seam and highwall mine it accordingly. This sequencing of highwall mining and backfill will adequately mine the full extent of the reserve over time. One additional area has been proposed to be highwall mined on the western perimeter of the South Taylor Pit (see Map 23A); however, at this time additional engineering studies and exploratory drilling evaluations may be needed to fully define the mineable reserve in this area. South Taylor/Lower Wilson—Rule 2,Page 89 Revision Date: 6/22/20 Revision No.: MR-220