2018-10-24_PERMIT FILE - C1982056A (2)

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(D) Contain an analysis describing the potential effect on the structure from subsidence of the subsurface strata resulting from past underground mining activities if underground mining has occurred; and (E) Contain a certification statement which includes a schedule setting forth the dates that any detailed design plan for structures that are not submitted with the general plan will be submitted to the Division. The Division shall have approved, in writing, the detailed design plan for a structure before construction of the structure begins. (ii) Each detailed design plan for a structure shall: (A) Be prepared by, or under the direction of, and certified by a qualified registered professional engineer with assistance from experts in related fields such as geology, land surveying, and landscape architecture; (B) Include any geotechnical investigation, design, and construction requirements; (C) Describe the operation and maintenance requirements for each structure; and (D) Describe the timetable and plans to remove each structure, if appropriate. (iii) If a reservoir has a capacity of more than 1,000 acre-feet, or has a dam or embankment in excess of 10 feet in vertical height from the bottom of the channel to the bottom of the spiIlwa,00r_ has a surface area at high waterline in excess of 20 acres then each plan under 2.05.3(4)(b) or © shall meet the applicable requirements of the State Engineer in accordance with C.R.S. 37-87-105. In cases where a sedimentation pond or impoundment meets or exceeds the criteria of 30 CFR 77.216 (a) then the permittee shall also comply with the applicable requirements of the Mine Safety and Health Administration 30 CFR 77.216(1) and (b) Sedimentation ponds Sedimentation ponds whether temporaryorpermanent shall be designed in conformance with the requirements of 4.05.6. Any sedimentation pond or earthen structure which will remain on the proposed permit area as a permanent water impoundment shall also be designed to comply with the requirements of 4.05.9. (c) Permanent and temporary impoundments Permanent and temporary impoundments shall be designed to comply with the requirements of 4.05.9. (d) Diversion Stream channel diversions and other diversions within the proposed permit area shall be designed to comply with requirements of 4.05.3 and 4.05.4. RESPONSE Sedimentation Ponds and Treatment Facilities—Surface Facilities Area The sedimentation control structures associated with the portal and surface facilities areas, as shown on Map 24, Surface Facilities, have been constructed in accordance with previously approved permits (CYCC Permit No. 79- 177 and TC Permit No. C-82-056). These structures include Ponds B, C, D, E, F, G, T, and the associated drainage collection ditches and discharge structures. TC also continues to operate Pond A, which was previously permitted, constructed, and operated under permits 79-177 and C-81-071 and is an MSHA impoundment, but is within and associated with areas for which final bond release has been obtained and is approved as a permanent impoundment. TC also jointly used Pond D with CYCC (Permit C-81-071). TC assumed responsibility and reclamation liability for Ponds B, C, D, E, F, G, and T. Design infonnation for the ponds, and associated ditches and culverts, is presented in Exhibit 8. Maintenance, operation, and removal requirements for each of the sedimentation ponds and RN 17-07 2.05-76 02/15/18