2010-03-29_REVISION - C1981019 (3)

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• designed to confirm that the operation is not causing material damage pursuant to Rules 2.06.8(5)(a)(iii) and 4.24. This information has not been provided in the PR-03 application. Colo wyo Response: Colowyo has had multiple discussions with the Division regarding the Gossard Loadout area designation as an alluvial valley floor during the course of negotiations involving TR-72. Colowyo continues to contend this area, including the Collom area coal transport road, etc. can no longer be described as an alluvial valley floor due to the natural massive down cutting of Wilson Creek's stream channel in the mid-1980's and subsequent lowering of the water table, precluding "re-establishment of hydrologic function" to pre-mass wasting event conditions. Colowyo has provided the Division with additional information that illustrates significant downcutting of the stream channel both above and below the intended path of disturbance as illustrated on Map 25E Sheet 5 of 9 (Collom Access Road Plan/Profile). Utilizing the evaluation criteria and conclusions reached for alluvial valley fill determination in the Collom Gulch and Jubb Creek drainage areas, Colowyo has amended Section 2.06.8 to reach the reasonable conclusion the Gossard Loadout Area and area to be disturbed by the construction of the Collom Access Road do not qualify as alluvial valley floors. The following commentary has been added to the end of Section 2.06.8: • "The same conclusions may be reached for the area of proposed disturbance for construction of the Collom Access Road in the vicinity of the Gossard Loadout Facility (Map 25E Sheet 5 of 9): • Alluvial materials are present in the valley bottom of the Gossard Loadout complex, and lower reaches of the Lower Wilson drainage, but the materials are intermixed with significant fractions of colluvium and sheetwash from adjacent slopes and the mass wasting event experienced in 1983-1984. • Based on an average depth to groundwater of approximately 21 feet for the existing alluvial groundwater well know as "Gossard Well" (2009 Annual Reclamation Report) since 1983, subirrigation within this valley bottom is very limited. Monitoring well MW-95-02, located in the area hydrologically above the proposed road corridor portrays similar depth to water conditions averaging 25.1 feet from 13 measurements taken in 1996, 1997 and 2005 (Table I - Groundwater Parameters, from August 16, 2005 letter to Jim Stark from Walsh Environmental). • Active erosion in the stream channels is causing further incision and reduced flood frequency, reducing the ability of this valley bottom to support any agricultural use other than rangeland or dryland agriculture. There is no evidence of "modern terracing" in the area proposed for disturbance near the Gossard Loadout facilities. • Local and regional agricultural economics are prohibitive to developing irrigation projects within this valley bottom, and such practices are in decline locally. • Historical irrigation activities associated with the "diversion structure and ditch" located hydrologically above the proposed access road path, diverted water around the existing grain fields, under County Road 17, outside the current permit boundary to the Colowyo Mine C-1981-019 page 8 of 16 25 March 2010 Permit Revision 03 - Collom Permit Expansion