2016-12-07_REVISION - C1982056 - Laserfiche WebLink

Home Browse Search

TWENTYMILE COAL, LLC - FOIDEL CREEK MINE (C-82-056) TR16-86 SWMD THICKENER UNDERFLOW BOREHOLE AND PIPELINE TECHNICAL ADEQUACY RESPONSES 2 (12/16) 2.05 — Operations and Reclamation Plan Based on TC's response letter to the Division's completeness review, the variance originally requested to disturb areas within the stream buffer zone may no longer be necessary because TC has selected another tie-in location north of Haul Road C outside of the stream buffer zone. However, the letter alludes that there may be disturbance within the stream buffer zone but it will be within the disturbed areas of Haul Road C. Based on Map 24 Sheet 1, proposed to be revised with this revision, the pipeline will be placed on the south side of Haul Road C. Based on Map 29, Sheet 4, this disturbed area along Haul Road C is partially within the Foidel Creek Stream Buffer Zone at multiple locations on the south side of the road. Given this, it would appear land will be re -disturbed within the Foidel Creek stream buffer zone. Regardless if the area has been disturbed already, TC must explain how they will protect the hydrologic balance during pipeline installation, and afterward. Please revise section 2.05.6(3) (page 2.05-129) of the permit to discuss what measures will be taken to comply with Rule 4.05.18(1)(a)(b) and (c). The Division reviewed Exhibit 49S and 49K and could not find where TC has previously made the demonstration how the pipeline disturbance will comply with Rule 4.05.18. Response: The relevant permit text has been reviewed and revised to address protection of the hydrologic balance. The revised text pages accompany these responses for replacement/insertion in the PAP. 2. Exhibit 49S currently contains Drainage and Sediment Control System designs and SEDCAD models to jirst� Alternative Sediment Control (ASC) practices for the 6RT Borehole Pad and Access Road, 7RT Borehole and Pipeline and the 2MN Borehole. TC submitted design drawings for Option I and 2 for this project but did not submit SEDCAD models to justify ASC practices. Please submit these models to be included in Exhibit 49S. Response: In reality, drill pad size and construction are similar for most applications, so similar drainage design considerations would be applicable. In order to directly address the question, however, TC has completed SEDCAD designs for the proposed pads, which accompany these responses for insertion in Exhibit 49S. Given similarities in design and configuration, however, we would ask the Division to consider a generic drill pad drainage design in order to minimize the future need for similar redundant efforts. According to TC's response, SEDCAD designs for the proposed pads accompany the adequacy review responses. However, based on the adequacy review response email submitted, TC is waiting on a consulting firm to complete the SEDCAD modeling. Please submit these results when they have been completed, for review. Response: The SEDCAD modeling report accompanies these responses for insertion in Exhibit 49S. Note that the SEDCAD results indicate drainage changes which are reflected in revised Figure EX49S-F2 and Maps 23C and 24, which also accompany these responses. 3. Revised page 2.05-74.2 indicates that TC will install a light use road for this project. For the borehole pad option east of RCR 27, it is unclear where this road will be located. Page 2.05-74.2 indicates all of the access roads are shown on Map 24A. Please update Map 24A or update proposed Exhibit EX49S-F3 to show the location of the proposed light use road. Response: Exhibit EX49S-F3 has been reviewed and revised to clarify the location of the short access road required. The revised figure accompanies these responses for replacement in Exhibit 49S. 4. Proposed Revised page 2.05-84.6 and 2.05-32.5 indicates that thickener underflow pipelines will be a double HDPE pipe system in "critical areas". The cover letter for TR86 would indicate the entire