CCP 05-14-1990 - Laserfiche WebLink

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. A Delta Environmental W... Consultants, Inc. 1801 Highway 8, Suite 114 St. Paul, MN 55112 612/636-2427 FAX:612/636-8552 May 10, 1990 - Mr. Gary R, Berger Village of Arden Hills 1450 West Highway % Arden Hills, MN 55112 Subject: Well Abandonment Change in Work Scope Kern Milling Site Demolition Arden Hills, Minnesota Delta No, 10-89-385 Dear Mr, Berger: This letter addresses a change in work scope involving the abandonment of the water supply wells . at the Kern Milling facility in Arden Hills, Minnesota, On May 8, 1990, Bergerson-Caswell, Inc. (BCI), informed me that water supply wells NO.3 and No, 4 were significantly deeper than originally estimated. Well I.D. Estimated Depth Measured Depth (5-8-90) No.3 30 - 50 feet 131 + (fine sand) No.4 50 - 100 feet 222+ (fine sand) In addition, fine sand was encountered in both of these supply wells at the measured depths, lt appears that the sand has accumulated in the boreholes as a result of either: 1) borehole collapselheaving, or 2) pump operation which pulled fine sand into the borehole. In order to abandon these wells in accordance with the Minnesota Department of Health (MDH) Water Well Construction code, the fine sand material must be removed to confirm the actual depth of the borehole prior to initiating abandonment procedures, Verification of the borehole depth is necessary to ensure that a borehole penetrating multiple aquifers is abandoned properly and cannot serve as a conduit for potential cross contamination between aquifers, Bergerson-Caswell, Inc., equipment would be mobilized to the site and would be set up to air lift wells No, 3 and No.4. Air lifting operates a vacuum in the wcll and is an effective means of removing the fine sand, . Practical Solutions to Environmental Concerns