2023-12-21_PERMIT FILE - C1981044 (10)

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Pursuant to the finding required by Rule 2.07.6(2)(n), and on the basis of available • information, the Division finds the existing and proposed operation will not affect the continued existence of the previously discussed endangered or threatened species, or result in the destruction or adverse modification of their critical habitat. Due to the potential for Bald eagles to have encounters with power lines, there exists a "may affect, but not likely to adversely affect" finding for Bald eagles. X. Subsidence Subsidence was last detected in the July-December 1995 monitoring period, during the last period of active mining. Section 2.05 of the permit application explains that subsidence monitoring for the No. 5 Mine was discontinued on November 1, 1988 following completion of mining in the No. 5 Mine. Subsidence monitoring for the No. 6 Mine was suspended in October 1997 after being approved in Technical Revision TR- 30. Monitoring will resume at least one month prior to resumption of mining in the No. 6 Mine. The No. 6 Mine will use longwall methods to mine the E seam. The No. 6 Mine underlies the previously mined No. 5 Mine, which occurred in the F seam. A. Inventory of Structures and Renewable Resource Lands The permit application contains an inventory of structures and renewable resource • lands within the permit area (Table 78 and Map 25). The applicant identifies three private residences that are within the permit area, but are outside the area potentially affected by mining within the five-year permit plan area. The inventory also identifies various mine facilities, an AMOCO oil pipeline, County Road 107 (vacated to BTU EC), State Highway 13, a Denver Rio Grande and Western Railroad spur and irrigation ditches within the permit area. Renewable resource lands identified within the permit area include the alluvial valley floors of the Big Bottom area, the Yampa River and the Williams Fork Rivers, the Yampa and Williams Fork Rivers themselves, and several bedrock aquifers. Subsidence predictions vary, depending upon the mining methods utilized. Maximum predicted subsidence where two longwall panels overlap is 13.0 feet. The extraction height for both E and F seams is 10 feet each. For locales where one longwall panel underlies room-and-pillar workings, maximum predicted subsidence is 10.5 feet. In areas where only one seam has been mined using longwall methods, maximum predicted subsidence is 7.5 feet. Further information can be found in permit Section 2.05. While the mine is in active status, BTU EC has committed to submitting results of the monitoring program at least semi-annually. Maximum total subsidence of 10 feet has been reported in the subsidence reports. The longwall panel 2 of Mine 6 was proposed to undermine the Amoco pipeline. The predicted subsidence that could occur under this zone was estimated at 10.5 feet, since this would involve one longwall panel under room-and-pillar workings. In lieu of subsiding the pipeline, the operator opted to relocate the pipeline and not conduct full extraction of the coal within 100 feet horizontally of the pipeline. This 35