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. Page 1 of 2 <br /> Mike Infurna [EH] <br /> From: Tamorah Bryant[TamorahB@gtienv.com] <br /> Sent: Thursday, June 23, 2011 11:30 AM <br /> To: Nuel Henderson [EH] <br /> Cc: Jenny Weese; Ray Kablanow; GBetker@aol.com; Mike Infurna [EH] <br /> Attachments: 5072 ORC Application.pdf; 507 do-orp.pdf <br /> Nuel, <br /> Further to our conversation, please find attached additional information regarding ORC and the recent field <br /> parameter measurements for the 1245 West Charter Way site. <br /> ORC: <br /> Please find attached a pdf file of output generated from Regenesis software. After reviewing my notes, I <br /> realized that this information was reviewed and discussed with Regenesis technical staff, but was not included in <br /> the RAP Addendum as the data pertains to a slurry application. I have been assured by Regenesis technical staff <br /> that the 6-inch diameter borehole will allow for a sufficient application of ORC Advanced in sock form (i.e. <br /> sufficient pounds per vertical foot). <br /> Field Parameters: <br /> On June 3, 2011 GTI technical staff mobilized on site to collected groundwater parameters using low purge <br /> technique and a closed system to minimize the exposure of the groundwater to atmospheric air. The results of <br /> the field parameter collection are presented in the Semi-Annual report that has been prepared in the 2nd <br /> quarter, and I have included a pdf of a summary table for your review. Each of the eleven wells were observed <br /> to have negative ORP values and DO values below one, with the exception of the background well. It is our <br /> opinion that data from previous monitoring event may not have accurately reflected subsurface conditions, <br /> which we believe is an oxygen depleted environment. <br /> Borehole design: <br /> As we discussed, the control borehole/injection (IW-3)design will be revised to match the ORC <br /> borehole/injection well (IW-1), and will be constructed as a six-inch diameter well to a total depth of 25 feet, <br /> with screen interval from 15 to 25 feet bgs. We also discussed the construction of the air sparging <br /> borehole/injection well (IW-4), and per our discussion (which referenced previous teleconferences)the design of <br /> IW-4 will be modified such that the bentonite seal will be placed from 11 to 13 feet bgs. This will have the <br /> impact of allowing air sparging in the large diameter borehole where air can interact with water flowing through <br /> the column, rather than forcing it out into the formation as the lower seal would do. <br /> Please let me know if you have any questions, or need more information. I look forward to receiving the SJC <br /> EHD review and approval letter and permit documents at your earliest convenience. <br /> Thank you, <br /> Tamorah Bryant, P.E. <br /> Geological Technics Inc. <br /> 1172 Kansas Avenue <br /> Modesto, CA 95351 <br /> Tel 209 522 4119 <br /> 6/28/2011 <br />