SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Page 2 of 2 To: Vicki McCartney [EH]; Nuel Henderson [EH] Subject: 308 Grant Street - Remediation Ms. Vicki McCartney and Mr. Nuel Henderson: AGE has modified the proposed well screen interval for the proposed air-sparge well network for the sidewalk on Miner Avenue. Shallow wells are to be installed and two semi-shallow wells to sixty feet, representing the top of the well screen are proposed. Attached cross section depicts the wells. A pilot test of the wells at the base of hydrogeologic unit 1 or sixty feet with total depth sixty-five feet, will be conducted to evaluate the dissolved oxygen concentrations change in shallow wells near each sparge point (sve wells, MW-5 and MW-6). Each sparge well will be operated for five days at low flow operation (2-4 scfm with approximately 10-12 psi pressure) and monitoring will be conducted daily to evaluate the change in dissolved oxygen. The deeper well operation will be evaluated against the conclusion of the two mini-pilot tests to determine if air can be collected from a depth of six feet below surface grade. Following the test, full scale Soil vapor extraction and shallow air-sparging will commence. Thank you in advance for your help in this matter. Please call me if you have any questions. Sincerely, VVdbwn R. Little Caldornia Professional Geologist 7473 Oregon Registered Geologist G2254 Washington Licensed Geologist 2778 A&ewK*d GeoEnvironmental Inc. www.advgeoenv.com Slocklon • Santa Rosa• Monterey • Brea•Spokane • Reno• Dallas (800)511-9300 This email/fax message is for the sole use of the intended recipient(s)and may contain confidential and privileged information.Any unauowged review, use,disclosure or distribution of this email/fax is prohibited.If you are not the intended recipient,please contact the sender by email/fax and destroy all paper and electronic copies of the original message. 11/5/2012