2010-01-25_APPLICATION CORRESPONDENCE - C2009087

Home Browse Search

compared to those observed in the PSCM wells. Overall the data used, except for the constant-head tests at wells COV23 and CWU23, appear to fall within the regional data envelope. 13. On page 2.04-45, 2°a paragraph, should the words "aquifer test method" be changed to "slug test method"? SCCC Response: The revised text in Section 2.04.7 regarding slug test discussion has been reworded to clarify the intent. 14. For the calculation of vertical bedrock discharge into Grassy and Little Grassy Creek alluvium on page 2.04-49, please explain why a hydraulic conductivity value of 10-5 is used, rather than a value between 0.03 and 5 feet per day as shown for interburden (PSCM's overburden) in Williams and Clark's (1994) Table 4. SCCC Response: The calculation of vertical bedrock discharge into Grassy and Little Grassy Creek alluvium used the value for vertical hydraulic conductivity calculated from the data in Table 5 in Williams and Clark (1994). The values of 0.03 to 5 ft/d referenced in the comment are the range of horizontal hydraulic conductivity and therefore are not appropriate for calculating vertical discharge from the bedrock into the alluvium. Section 2.04. 10 15. Page 2.04-123 appears to introduce a new reference area, the "Yoast Haul Road Corridor- Improved Pasture/CRP" to Table 2.04.10-T5. This reference area is not depicted on Map 2.04.10-M1. Is this a third reference area, in addition to the Mountain Brush and Sagebrush reference areas? There is no discussion of the condition of this apparently new reference area or its application to reclaimed areas at PSCM. Please provide additional discussion, the location, and the application of the Road Corridor-Improved Pasture/CRP reference area. Also, Table 2.05.4-T4 includes only two reference areas, the Mountain Brush reference area and the Sagebrush reference area. Please ensure tables show a consistent number of reference areas. SCCC Response: The 2008 vegetation baseline studies encompassed an area sufficient to cover the anticipated PSCM permit boundary and other potential areas of mine and transportation related activity. A transportation corridor south of the existing Seneca II mine permit area to the Foidel Creek Mine facilities was under consideration at the time of baseline studies and so a reference area that would address any disturbances to improved pasture or CRP lands was a consideration. The existing and approved Yoast Haul Road Corridor-Improved Pasture/CRP reference area seemed appropriate and was thus included in the baseline sampling. This approach was presented to CDRMS in an April 2008 meeting covering baseline study plans and concurred with in an April 24, 2008 email from Tom Kaldenbach. In preparing the PSCM PAP, the transportation of coal was to be by means other than through the possible transportation corridor and the use of the Yoast Haul Road Corridor-Improved Pasture/CRP reference area was not required, but will remain a consideration for permit revisions should the corridor be reconsidered in the future. Table 2.04.10-T5 is now on page 2.04-145 and a note has been added that this reference area is a contingency for future operational considerations. 4