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0 <br />1.0 Introduction <br />This contingency action plan has been prepared at the request of the Minnesota Pollution Control <br />Agency (MPCA) to outline landfill gas (LFG) monitoring and contingency actions following closure <br />of Old Miller Dump in the eastern portion of the Northwest Quadrant Redevelopment Area (NW <br />Quadrant) in New Brighton, Minnesota. The project is enrolled in the MPCA's Voluntary <br />Investigation and Cleanup (VIC) Program (VP #18560). The planned response actions for dump <br />closure are outlined in the February 2008 Response Action Plan (RAP) for the eastern portion of the <br />NW Quadrant (Site). MPCA approved the RAP with comments in a letter dated May 15, 2008. <br />The RAP for closure of Old Miller Dump includes excavation and on-site consolidation of dump <br />materials and construction of a clean cover over the consolidated materials. An area -wide passive <br />venting system will also be constructed over the consolidated dump materials to intercept and <br />passively vent LFG generated from the dump materials. The LFG collection system will be <br />monitored through (1) a perimeter network of fifteen vapor wells around the dump, and (2) <br />monitoring of the ambient air at passive LFG vents. In addition, each new building at the <br />development blocks of the eastern NW Quadrant (Blocks A through E) will have its own sub -slab <br />venting system and associated monitoring. It is anticipated that the specifics of the building venting <br />systems and their monitoring will be finalized in separate RAPS or RAP Addendums by the <br />individual block owners similar to the process used for the first redevelopment at the eastern NW <br />Quadrant for Transoma Medical at Block C. <br />The MPCA requested additional details regarding LFG monitoring in their May 15, 2008 RAP <br />approval letter. Perimeter vapor monitoring well locations are shown in Figure 1. The process for <br />conducting the LFG monitoring is summarized in Figures 2 and 3, and described in the following <br />sections. <br />P:\Mpls\23 MN\62\2362489\WorkFiles\Eastern RAP 2008\LFG CAP\Revised March 2009 CAP\LFG Contingency Action Plan <br />Revised March 2009.doc <br />