Letter regarding Abandonment of Monitoring Well MW-6, Tutu Service Station Investigation, St. Thomas, U.S. Virgin Islands
'GERAGHTY <S? MILLER, INC. Environmental Services Ground Water Engineering Hydrocarbon Remediation Education August 26, 1992 Caroline Kwan U.S. Environmental Protection Agency 26 Federal Plaza, Room 737 New York, New York 10278 Re: Abandonment of Monitoring Well MW-6 Tutu Service Station Investigation St. Thomas, U.S. Virgin Islands Dear Ms. Kwan: As you know, Monitoring Well MW-6 was installed after incurring difficult drillii* conditions in the 70-foot deep corehole at this location. The coring was completed on My 23, 1992. This 3-inch diameter corehole was intended to preceed the reaming and installation of Monitoring Well MW-6D. However, as the corehole was being reamed to a diameter of 10 inches, formational collapse occurred, Collapsed rock and soil filled the 10-inch diameter hole from approximately 25 to 35 fwt below grade. In order to minimize re-drilling efforts, the field crew decided to set the shallow Monitoring Well MW-6 in the remaining drill hole rather than abandon the hole. …
Download the original document · Plain text (TXT) · Browse the archive · How this archive works
Original source: https://semspub.epa.gov/src/document/02/64882
SHA-256 6dd0b7e4e340f5086d6b481b94475dac51fb7417a7ee85e997c2763531c528e4
Re-using this document
CERCLA administrative record
Our description, tagging, arrangement, extracted text and machine transcripts are released under CC0 1.0. We assert nothing about the document itself.
Archive identifier LF-6dd0b7e4e340
Document text
'GERAGHTY <S? MILLER, INC. Environmental Services Ground Water Engineering Hydrocarbon Remediation Education August 26, 1992 Caroline Kwan U.S. Environmental Protection Agency 26 Federal Plaza, Room 737 New York, New York 10278 Re: Abandonment of Monitoring Well MW-6 Tutu Service Station Investigation St. Thomas, U.S. Virgin Islands Dear Ms. Kwan: As you know, Monitoring Well MW-6 was installed after incurring difficult drillii* conditions in the 70-foot deep corehole at this location. The coring was completed on My 23, 1992. This 3-inch diameter corehole was intended to preceed the reaming and installation of Monitoring Well MW-6D. However, as the corehole was being reamed to a diameter of 10 inches, formational collapse occurred, Collapsed rock and soil filled the 10-inch diameter hole from approximately 25 to 35 fwt below grade. In order to minimize re-drilling efforts, the field crew decided to set the shallow Monitoring Well MW-6 in the remaining drill hole rather than abandon the hole. Monitoring Well MW-6 consists of a flush-mounted 4-inch diameter stainless steel casing and screen. The screened interval is from 4 to 24 feet below grade. CO As was agreed in a conference call between Caroline Kwan, USEPA; Sally Odtend, CDM Federal Programs; and Thomas V. Danahy, Geraghty & Miller, Inc.; Monitoring MW-6 will be abandoned because the unsealed 70-foot deep corehole may result in anomalous water- o level or water-quality data. The well abandonment and sealing procedures are outlined below. H ^ 201 Vfe&t Passaic Street, 3rd Floor • Roctoelle Pkrk, New lensey 07662 • (201) 909-0700 • FAX (201) 909-0567/OS« O : O a *64882* 64882 GERAGHTY & MILLER, INC. The borehole will be reamed to the original depth using air-rotary and/or wash-rotary techniques. Initially, the drill crew will attempt to remove the 4-inch diameter stainless steel casing. If unsuccessful, the casing and screen will be left in place and the bottom of Hie 4-incfc well will be drilled through to minimize further collapse of the formation. A 3-inch diameter rotary bit will be extended to 70 feet. Potable water will be used to cool the bit and remove cuttings. If necessary, bentonite mud may be used to remove cuttings from the hole, Upoa reaching 70 feet, the corehole will be tremie-grouted to the surface by placing a bentoni*- cement grout using the drill string or a tremie pipe. After grouting, the stainless steel casing will be cut-off at least 5 feet below grade (if it is not entirely removed). Clean backfill material win be placed in the upper 5 feet of the hole and the paving will be restored. If you have any questions, please call. c: Ana Gloria Ramos, TEIC Sally Odland, CDM Federal Programs Sincerely, GERAGHTY & MILLER, INC. Thomas V. Danahy Senior Scientist/Project Manager Daniel A. Nachman j Vice President/Project Director TUT 006 1759 o <3. 3 1 T 3 H O O M — O : O T 'so SENT BY:. TUT 006 1760 V d 3 T T 3 H O O H — 1ACV S O - ' O T SS '93 'SO