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—a Harlin Knoll [EH] From: Robert Ellgas [rellgas@msegrp.com] Sent: Friday, July 31, 2009 3:35 PM To: Todd Del Frate Cc: Tyrone Evans; Anne Conner; Derrik Sandberg; Harlin Knoll [EH]; Matt Power; Steve Rosenbaum; Eugenio Diaz Subject: Re: PG&E McDonald Island Well Decommissioning a Todd, Because former COCs are no longer present in site soil and groundwater at concentrations above background, SJCEHD is permitting pressure grouting instead of overdrilling. This makes the decommissioning process much simpler. SJCEHD has a requirement for neat cement"mushroom caps"to be placed over the tops of the well casings, which will be cut off at 2.5' depth bgs with the caps installed to a diameter 12" greater than the well borehole diameters. Soil removed from the holes for installing the mushroom caps can backfill the holes. FYI, two of the wells that were planned for decommissioning (WOW, a well point, and P=%, a piezometer)could not be located during reconnaissance by a surveyor using PG&E survey data and a PG&E facility figure that presumably plots their locations based on the survey data. RSI will be excavating around the plotted location of P-6A, whose PVC riser was destroyed sometime in 1999. However, WP-1 could not be located based on survey coordinates listed for the well point, by using similar survey coordinates listed for other wells, nor by visual observation of mangled riser location and widespread metal detection around the area of the riser(WP-1 was a 1.5" steel casing). It is likely that nothing else can be done to locate WP-1. SJCEHD will allow these wells to remain in place without grouting if we have made multiple efforts to locate them to no avail, primarily because they can no longer act as conduits for former site CDCs. This will be noted in the Well Decommissioning and Site Closure Report. No problem at all if you and a student trainee would like to visit the site on Tuesday morning at 09:00 to observe the operations. The work will be conducted in Level D PPE, and PG&E requires that all site visitors view a safety video before entering the site. We will arrange this with the facility staff. I will be happy to accompany you on the site visit, as I will be performing one or two QC oversight checks on the work anyway. I can meet you at the security station located before the bridge crossing over to the island. If you are delayed for any reason please call me on my cell, 510-412-1817 and I will plan accordingly. Robert A. Ellgas, Ph.D. Program Manager MSE Group 302 Pendleton Way Oakland, CA 94621 510-383-9600 510-383-9300 fax From: Todd Del Frate <TDelFrate@waterboards.ca.gov> To: Robert Ellgas <rellgas@msegrp.com> Cc: Tyrone Evans <tevans@msegrp.com>; Anne Conner <APB1@pge.com>; Derrik Sandberg <Derrik@RSIdrilling.com>; Harlin Knoll <hknoll@sjcehd.com>; Matt Power <MPower@waterboards.ca.gov>; Steve Rosenbaum <srosenbaum@waterboards.ca.gov>; Eugenio Diaz <eugeniodg@yahoo.com> Sent: Friday, July 31, 2009 8:40:00 AM Subject: Re: PG&E McDonald Island Well Decommissioning Goodmorning Robert, glad to hear this project is coming to an end. I would like to make a site visit on Tuesday morning around 09:00. Are you required by San Joaquin County to drill these wells out? It is my intention to bring a student along for some minor training. They are hazmat trained and will have the appropriate level D PPE. If there is any problem with that please notify me. 8/3/2009