Appendix I-2.4 Sub-cell 3 Monitoring Well Details

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1 Appendix I-2.4 Sub-cell 3 Monitoring Well Details

2 Appendix I-2 Groundwater Monitoring Network 2008/2009 Annual Groundwater Report, Clean Harbors Lambton Facility Landfill Appendix I-2.4 Sub-Cell 3 Monitoring Well Details The hydraulic control layers (HCLs) installed in Sub-cell 3 were designed to effectively mitigate the potential for transport of contaminants through the seeps identified in Sub-cell 3, Cell 18 to the underlying Interface Aquifer, by eliminating preferential advective movement through the seep openings. This effect is achieved by maintaining a hydraulic pressure head elevation in the HCL at a lower level than the hydraulic pressure head elevation in the underlying aquifer. This produces an upward gradient thus preventing downward movement of contaminants by advective processes. Performance monitoring of the HCL includes hydraulic and water-quality monitoring that is currently conducted at four locations. These locations include (EW1a-01, EW2a-01) installed in the north HCL and south HCL respectively, and existing wells (PW1-N and PW2-S) completed in the interface aquifer. Monitoring well locations are presented in Figure I Borehole logs for these monitoring wells are included on the CD-ROM located in Appendix I-4.8. Various other deep wells were installed in 1999 to investigate the seeps. In late August 2003, wells TW2-99 (TEST 2-99) and TW3-99 (TEST 3-99) were decommissioned to allow for future cap placement in the Cell 18, Sub-cells 3 and 4. The decommissioning was completed by backfilling the screen interval of each well with clean silica sand. A 1.5 m seal of bentonite chips (trade name Baroid Hole Plug) was then placed above the screen interval. The remaining annulus was then backfilled to the approximate waste level (~195.0 masl) with bentonite/portland cement grout. An additional 1.5 m hydrated bentonite chip seal was then placed above the grout once it had been allowed to cure. Decommissioning logs are also included within this appendix. On August 12, 2004, well TW4-99 (TEST 4-99) was decommissioned to allow for future cap placement in the Cell 18, Sub-cell 3. The decommissioning was completed by backfilling the screen interval of the well with clean silica sand. A 1.2 m seal of bentonite chips (trade name Baroid Hole Plug) was then placed above the screen interval. The remaining annulus was then backfilled to the approximate waste level (~195.0 masl) with bentonite/portland cement grout. An additional 1.5m hydrated bentonite chip seal was then placed above the grout once it had been allowed to cure. In July 2005, wells PW2-N and PW3-N were decommissioned to allow for the construction of the cap keyway along the north side of Sub-cells 4 through 9. The well riser and well screen were removed from the ground; the open borehole annulus was then flushed with fresh water. Bentonite chips (trade name Baroid Hold Plug) was then placed through the bedrock portion of the borehole. The annulus was then grouted with a minimum 30% solids bentonite (Baroid Benseal) grout to a level of about 1 m below the ground surface. The remaining annulus was then filled with bentonite chips. J0008-T4 I-2.4-1

3 Appendix I-2 Groundwater Monitoring Network 2008/2009 Annual Groundwater Report, Clean Harbors Lambton Facility Landfill With the removal of depressurization pumping equipment from PW-1N, monitoring at the northern perimeter of the Sub-cell 3 structure has been transitioned over the past two years from TW1-99D (TEST 1-99) to PW1-N. TW1-99D was decommissioned on December 16, 2008 by All Terrain Drilling Limited of Waterloo, Ontario under the supervision of AECOM staff. A copy of the decommissioning record (letter report) is attached. Decommissioning logs are provided on the CD-ROM located in Appendix I-4.8. A summary of the above well status is provided in the following table. Summary of Current Sub-cell 3 Well Status Active Well EW1a-01 EW2a-01 PW1-N PW2-S Inactive Wells (to be decommissioned) PW1-S Decommissioned Wells PW2-N PW3-N TW1-99 (TEST 1) TW2-99 (TEST 2) TW3-99 (TEST 3) J0008-T4 I-2.4-2

LEGEND PETROLIA LINE PW1N HYDRAULIC CONTROL LAYER MONITORING WELL EW1a-01 HYDRAULIC CONTROL LAYER EXTRACTION WELL PW1N EW1a-01 CELL 18 EW2a-01 PW2S CELL 17 LEACHATE RESERVOIRS NOTES: 1.

4 LEGEND PETROLIA LINE PW1N HYDRAULIC CONTROL LAYER MONITORING WELL EW1a-01 HYDRAULIC CONTROL LAYER EXTRACTION WELL PW1N EW1a-01 CELL 18 EW2a-01 PW2S CELL 17 LEACHATE RESERVOIRS NOTES: 1. BASEMAP PROVIDED BY INSPEC-SOL INC. (2009). 2. AIRPHOTO PRODUCED BY FIRST BASE SOLUTIONS, (2006) m TELFER ROAD SCALE CLEAN HARBORS CANADA INC., LAMBTON FACILITY LANDFILL A SIZE 216 x 279 mm CELL 16 SUBCELL 3 MONITORING WELL LOCATIONS 2008/2009 MONITORING REPORT PROJECT NUMBER J00008 DRAWING NUMBER I ISSUE/REVISION FILE: I dwg DATE PLOTTED: 18-Sep-09 DRAWN BY: TFB

5 TW1-99 (TEST 1) Decommissioning Record

6 December 18, 2008 Project Number: Mr. Timothy Bechard Facility Manager Clean Harbors Canada, Inc. R.R. #1, Telfer Sideroad Corunna, ON N0N 1G0 Dear Mr. Bechard: Re: Decommissioning of TW1-99, Sub-cell 3, Cell 18 TW1-99 was decommissioned to allow for future placement of cap material over the Sub-cell 3 mitigation area. Decommissioning was conducted on December 16, 2008 by All-Terrain Drilling Ltd., of Waterloo Ontario, under the supervision of qualified AECOM staff. The decommissioning procedure was as follows; the bottom depth of the well was verified using a weighted tape; the outer steel protective casing was cut to allow good access to the steel well riser pipe (approximately 0.4 m above ground surface) a tremie pipe was used to place 2.30 m of grade 00 sand within the screen interval and allowed to settle; 1.83 m of bentonite pellets (holeplug) was placed over the sand layer with the use of a tremie pipe and allowed to settle; a cement/bentonite grout slurry was injected into the well with the use of a tremie pipe from the top of the bentonite plug to the top of the well riser pipe. The decommissioning log for TW1-99 is attached for your records.

7 Page 2 Clean Harbors Canada Inc. December 18, 2008 We hope the letter satisfies your requirements at this time. Please feel free to contact the undersigned if you have any questions. Sincerely, Gartner Lee Limited doing business as AECOM Timothy Boc, Environmental Technician timothy.boc@aecom.com TFB: Encl. cc: File (90040_tw1-99_decom.doc)

8 DECOMMISSIONING LOG PROJECT: Decommissioning of TW1-99 (Sub Cell 3) Clean Harbors Canada, Inc. Lambton Facility, Corruna, Ontario FOR: Clean Harbors Canada, Inc. BOREHOLE: TW of 2 DATE: 16 December 2008 GEOLOGIST JAA ELEVATION m ASL DEPTH (m) STRATIGRAPHY STRATIGRAPHIC DESCRIPTION MONITOR DETAILS & NUMBER NUMBER INTERVAL TYPE SAMPLE N VALUE % WATER % REC % RQD COMMENTS 2 CLAYEY SILT TILL (ST. JOSEPH TILL) Mottled light brown to grey clayey silt till fill, trace sand and gravel, massive to laminated, APL to WTPL, hard to firm CLAYEY SILT TILL (BLACK SHALE TILL) Grey clayey silt till, trace disseminated sand and gravel clasts, massive, WTPL, stiff to very stiff. Contact inferred based on auger cuttings and Cell 18 excavation Printed: 17 Dec 08

9 DECOMMISSIONING LOG PROJECT: Decommissioning of TW1-99 (Sub Cell 3) Clean Harbors Canada, Inc. Lambton Facility, Corruna, Ontario FOR: Clean Harbors Canada, Inc. BOREHOLE: TW of 2 DATE: 16 December 2008 GEOLOGIST JAA ELEVATION m ASL DEPTH (m) STRATIGRAPHY STRATIGRAPHIC DESCRIPTION MONITOR DETAILS & NUMBER NUMBER INTERVAL TYPE SAMPLE N VALUE % WATER % REC % RQD COMMENTS Light grey sandy silt lens (85 mm thick) at m, dry Becoming WTPL to APL and stiffer at m. BASAL TILL Grey cobbly silt till with occasional clay and trace sand, dense to cemented, wet. SHALE (KETTLE POINT FORMATION) Black shale, fresh, medium hard, good quality. -Fresh horizontal fracture at m. - Fresh horizontal fracture at m. -Bitumen coating on fracture (subhorizontal) at m. -Fresh vertical fracture approximately 2.2 cm deep from m to m. Borehole terminated at m in shale. Printed: 17 Dec 08

Sent: Friday, June 24, :17 PM. Subject: RE: Southwood 4 - Monitoring Well update

Sent: Friday, June 24, :17 PM. Subject: RE: Southwood 4 - Monitoring Well update Sent: Friday, June 24, 2016 5:17 PM Subject: RE: Southwood 4 - Monitoring Well update Please see attached for a copy of our Draft Borehole Logs, Draft Borehole Location Plan and Interim Ground Water Monitoring