2016-10-13_REVISION - M2001017 - Laserfiche WebLink

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ENVIRONMENT, INC. PAGE 2 SEPTEMBER 1 , 201 6 ronment, Solid Waste Division, they confirmed that a CD would be required. L.G. Everist, Inc . will obtain a CD, as de- scribed in the MOU provided, prior to filing the Technical Revision to implement the Inert Fill alternate plan. EXHIBIT G -Water Information (Rule 6.4.7): This site will employ compacted clay liners to satisfy SEO requirements. These liners, in conjunction with site dewatering prior to liner placement, may result in groundwater mounding or shadowing issues, therefore, a groundwater level monitoring and mitigation plan will be required for this site. Please submit a plan for DRMS approval that illustrates, at a minimum, groundwater level monitoring points, level measuring method, frequency and reporting, as well as impact mitigation trigger levels and proposed mitigation options. Attached is a Groundwater Monitoring and Mitigation Plan describ- ing the items you requested. We are in the process of locating and installing 4 Piezometers around the south, west and north sides of Area C. There are 3 lined reservoirs in the near vicinity of the mine, 2 along County Road 26 and 1 east of the mining area. Also attached is a new map, Map Exhibit G-2 showing the proposed locations of the Piezometers . According to the maps submitted with the application, a portion of the site along the north permit boundary is within the 100 year flood plain. The application as submitted does not address how the permittee will prevent damage to the lined reservoirs from flood events to ensure long term stability of the site- please address. Many operators incorporate engineered inlet/outlet structures to lined reservoirs to allow flood flows to enter and exit the reservoir in a controlled fashion. These structures are intended to prevent damage to the clay liners and prevent possible head-cutting damage due to flood events. The location of the 100-year flood plain shown on the maps was from an old version of the FEMA FIRM map for this area. A revised FIRM map was issued in January 2016 and it shows the 100-year flood plain is no longer on the property. I have attached a Firmette showing the permit area (found at http://fema.maps.arcgis.com/apps/webappviewer/index.html?id=49069b9l cl4a411 fa8defccf5c1 f6266) I added the Affected Lands line to the map for reference . Since the reservoirs are not in the flood plain we prefer not to include spillways for them. I have enclosed copies of revised Map Exhibit C, C-1, E & F with the flood plain re- moved. EXHIBIT L - Reclamation Costs (Rule 6.4.12): (1)All information necessary to calculate the costs of reclamation must be submitted and broken down into the various major phases of reclamation. You must provide sufficient information to calculate the cost of reclamation that would be incurred by the state. DRMS will recalculate reclamation costs when all adequacy issues are resolved. Based on conditions observed during pre-op inspection, a significant amount of clean-up, lining and re-sloping work remains to be completed in Area B. The remainder of Area A will need to be backfilled to approximate original grade. Estimates for these tasks, broken down by task, and including information such as material quantities required, push distances, equipment utilized, etc. should be provided in this Exhibit. Exhibit L contains all of the information noted. The minor revisions we made during this response do not affect the overall numbers provided.