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10 January 2011 <br /> AGE-NC Project No. 02-0962 <br /> Page 2 of 3 <br /> WELL DESTRUCTION PROCEDURES,.- <br /> On 08 and.09 December.2010,,monitoring wells MIN-1•through MW-7 were destroyed at <br /> the site, under-EHD oversight;.utilizing a CME-75-limited access track mounted Arill rig <br /> equipped with 8.25-inch diameter,hollow stem aug, rs. The drill rig and two-person crew <br /> were,supplied•by All Well Abandonment;of,Placerville, California. <br /> i <br /> Prior to destruction activities, each well casin w 5 sounded with a Solinst water,level <br /> g� i <br /> meter to ensure no obstructions were present in the casings.Subsequently,well boxes and <br /> caps were removed to expose the well casings. <br /> Monitoring wells MW-4-and MW­7 were drilledrout to the notal depth plus one foot-bsg,of= <br /> each boring (i.e., 36 feet%bsg.and-81-feet..bsg, r spectively), using &inch hollow=stem <br /> augers.All original well construction-materials were moved{including well casing;screen; <br /> filter pack and annularseal)to ensure that no residu I contamination was sealed within the <br /> abandoned borehole The remainingborehole was ackfilled to surface grade with a grout- <br /> mixture and completed at the surface with concre . A ratio of three gallons oCwater for <br /> every 50-pound-sack of portiand'cementewas utiliz W to prepare the groutmixture: <br /> Monitoring wells MW-1, MW-2; MW-3, MW-5 and W-6 were destroyed by grouting the <br /> well casings under pressure and,utilizing-8-inch hollow stem augers,over-drilling each well <br /> to five feet bsg. The wells-were fitte&with a.pressure tight adapter connected oto a hose <br /> extending-from a grout mixer:A-grout-mix ratio consisted of-three gallons of water forevery. <br /> 50-pound sack of portiand-cement.-The grout mixt ire was pumped into each well casing., <br /> under approximately 540 pounds per-square inch psi)of,pressure. The top three feetof, <br /> each well casing was removed and the borings wer grouted to the near surface using the <br /> portland cement grout mixture and completed attit.a surface with concrete. <br /> Well construction materials and auger returns generated by drilling were containerized in <br /> properly labeled Department of-Transportation ( OTYapproved model 17H 55-gallon <br /> drums and were stored-on-site. <br /> NON-HAZARDOUS WASTE DISPOSAL <br /> On 22 December,2010, approximately 2,370 pours Js of soil cuttings and solid waste (i.e. <br /> well materials)were containerized-in 55-gallon dru ns and were removed from the site by <br /> Slaby Environmental, Ina.,of Borrego Springs,Cali ornia: Non-hazardous solid waste was <br /> transported and disposed of•at Westem Environmi intal Inc., located in Mecca, California. <br /> A copy of the non-hazardous waste manifest is included in Appendix D. <br /> Advanced GOEnvlienntents4 Inc. <br />