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-8- include data to substantiate the applicants subjective judgment of "normal movement". Further, this section of the application states that, because the work in this permit term (five years) will include only development work, which will preclude subsidence, no subsidence monitoring is planned for this permit term. This subjective opinion should also be better supported by data or literature references within the application. Minor subsidence may occur and a properly designed monument monitoring system could allow the collection of valuable rock mechanics data which could be utilized in subsidence prediction for future permit operations. A determination of the presence of renewable resource lands is contingent on the receipt of appropriate baseline data as specified in other portions of this correspondence. oors With regard to alluvial valley floors (AVF's) a minimum amount of information that is acceptable to the State of Colorado includes the following (206.8)(3)). 1. In light of the controversy over the adequacy of the current ground water data Sheridan Enterprises must first define the ground water system in the area proposed to be mined. lJith an understanding of the ground water system and surface waters in the area Sheridan Enterprises must quantitatively justify the ground and surface t•~ater adjacent areas. 2. A reconnaissance level alluvial valley floor study is required from the operator. This study should comoly ~•iith section 4.25 of the regulations and should include a map of the total life of mine area (on aUSGS 72 minute topographic sheet base) shoving alluvium in these streams including valley bottoms and flood plain terraces. Identification of areas of existing or historic flood irrigation practice, riparian vegetation which indicates subirrigation, and a discussion of regular flood irrigation practice in areas of similar or smaller drainage size for considering any potential subirrigation must be included. 3. Once the adjacent area is defined and all valleys holding streams are appropriately mapped two approaches to a permit may be taken. First the applicant may affirmatively demonstrate the presence of an alluvial valley floor based on available data or second, submit sufficient field data to enable the Division to make an evaluation regarding the existence of the probable alluvial valley floor in the adjacent area and to determine which areas, if any, require additional information for the Division to make a final AVF determination (2.06.2(3)(b)). The first option could be a less rigorous demonstration to show that an AVF exists while the second approach would be a more rigorous justification why an AVF does not exist. In either case if a positive AVF determination is made then Sheridan Enterprises must comply with 2.06.8(4) and 4.24. All demonstrations discussing material damage etc. must be quantitatively justified. Please refer to the June 11, 1980 OSM AVF guideline for further direction. 2.05.6(3)(b)(iv) This section requires that a narrative be supplied by the applicant of probable hydrologic consequences of tfie mine. No such narrative is given. Please provide this narrative with sufficient baseline data to support conclusions.