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Civil & Mining Engineering <br />Engineering Geology <br />Tunnel Engineering & Construction Management <br />Rapid Excavation/Support Systems <br />7, ---_' <br />S ub Terra Inc,ctive/Abandoned Mine Subsidence <br />� Quality Assurance /Quality Control <br />- Safety Monitoring of Structures <br />Blast Optimization / Vibration Monitoring <br />Mine & Quarry Permitting <br />Material Science / Laboratory Testing <br />Monday, April 11, 2016 <br />Mr. Mike Berdine <br />Manager —Technical Resources <br />Peabody Energy <br />Twentymile Coal, LLC <br />Foidel Creek Mine <br />Re: Subsidence Mitigation During 9 -East Undermining of the Energy Spur at the Foidel Creek <br />Mine. <br />Dear Mike: <br />Please find attached our Final Report addressing mitigation measures when 9 -East longwall <br />undermines the Energy Spur at the Foidel Creek mine. The report includes a prediction of <br />expected subsidence along the affected section of the rail line and estimates for re -ballasting to <br />maintain the track within gradient limits previously provided by Union Pacific Railroad. <br />The existing track does not currently meet that maximum gradient criterion with sections up <br />gradient of where the Energy Spur crosses 9 -East at 2% or higher gradient. However, that <br />situation will change when 8 -East is mined and it is anticipated that track gradients can be lowered <br />as panels to the south are mined out. <br />This report was prepared in accordance with our proposal dated February 13, 2016, your <br />authorization to proceed of March, 2016, and our MPA with Peabody Energy that was completed <br />and signed on July 31, 2012. <br />Thanks for the opportunity to be of service. If you have any questions please do not hesitate to call <br />us at 425-888-5425. <br />Sincerely, <br />Chris D. Breeds, PE, PhD <br />President, SubTerra, Inc. <br />Post Office Box 520, 218 East North Bend Way, North Bend, WA 98045-0520 <br />Phone (425) 888-5425 Web Site: www.subterra.us Email: info@subterra.us Fax (425) 888-2725 <br />