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AUGUST 8, 2011 <br />MAY DAY MINE CLASS II - SUBMITTAL 2 REVIEW <br />PAGE 8 OF 15 <br />c. References to "attachments" need to be replaced with the specific document name and <br />date, as outlined herein, to avoid confusion as the referenced documents come to be <br />updated and /or separated from the Work Plan. <br />4. Page 5 states "buttresses will be constructed per design and specifications" but buttresses are <br />not mentioned again in the Work Plan nor are they shown in the Construction Plans. <br />a. Please rectify discrepancy and provides details within the Plan Set for any potential <br />retaining walls or buttresses and specifications within the Work Plan corresponding to the <br />plan details (based on the current approach where construction plan specifications are <br />provided within the Work Plan). <br />5. Page 7 describes multiple scenarios for retaining structures, such that responsibility is shifted to <br />the contractor to determine during construction how the road fill will be handled and <br />reconstructed. <br />a. The Work Plan shall be revised to state exactly how the road shall be reconstructed and <br />retained (corresponding to Construction Plan Set to ultimately be used) <br />b. OR, the Construction Plan Set shall be revised to show how each of the alternatives <br />outlined in the Work Plan will be installed (specific cross - sections, tying in of proposed <br />and new grades, retaining walls details, etc) <br />6. Page 8 states "if road slumps or partially fails ... and the materials impact the wetland at the <br />base of the fill, Wildcat will mitigate the impacted area by creating wetland offsets similar to <br />the offsets currently required by the USACE where offsets have been" established at a 1 to 1 <br />ratio. <br />a. The existing wetlands offset do not appear to be successful. Future offsets for unpermitted <br />wetlands impacts may be at higher ratios that 1 to 1. For wetlands offset to be a viable <br />plan, the following at a minimum needs to be provided: <br />i. Quantification of fill and footprint that could impact wetlands <br />ii. Showing potential offset areas on plans <br />iii. Providing information on the potential wetlands impact to the USACE and addressing <br />any resulting USACE comments <br />7. Page 7 addresses drainage ditches and references "Exhibit C — Mine Plan Table C -2" for <br />drainage design calculations. The same section states that "D(50) riprap of b +6 inches shall be <br />placed in ditches where slopes are in excess of 10 %. <br />a. Exhibit C is an "Environmental Protection Plan" and Exhibit D is a "Mine Plan". Neither <br />contains a Table C -2 or drainage calculations. Exhibit E is labeled "Stormwater <br />Management Plan", but there was no material provided. <br />b. It appears the document that contains the most substantial information on drainage is the <br />2.22.2011 submittal in a document labeled "Section 3(e): Existing and Proposed <br />Improvements Drainage and Development Plan". This document contains some <br />information relevant to the design of the access road include drainage calculations and <br />erosion control BMPs, but still does not substantially addressed issues associated with the <br />access road. <br />c. A drainage evaluation addressing critical access road issues is still needed. <br />PLANNING DEPARTMENT • 970.382.6263. • 1060 E. 2ND AVE. • DURANGO, COLORADO • 81301 <br />