INVESTIGATION RESULTS

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2 September 13, 2011 Burt Fleischer, R.E.A., R.E.P. Director, Environmental Affairs Hilmar Cheese Company 9001 N. Lander Avenue Hilmar, CA Subject: Revised Work Plan for Supply Well IN 1 Destruction Hilmar Cheese Company, Hilmar, California Dear Mr. Fleischer: As requested by the Regional Water Quality Control Board, Central Valley Region (RWQCB) letter dated August 18, 2011, Jacobson James & Associates, Inc. (JJ&A) has prepared this Revised Work Plan for Supply Well IN 1 Destruction (Work Plan) for the Hilmar Cheese Company (HCC) facility located at 9001 Lander Avenue, Hilmar, California (the Site, depicted on Figure 1 of Attachment 1). This Work Plan evaluates alternative procedures to complete the destruction of supply well IN 1. The location of IN 1 is illustrated on Figure 2 (Attachment 1). Well construction information is included as Attachment 2. HISTORY OF IN 1 Construction of well IN 1 was completed in December 1989 by Calwater Drilling Company, Inc. for use by HCC as an industrial supply well. According to the DWR Well Drillers Report, the 20 inch diameter boring was drilled to a total depth of 302 feet below ground surface (ft bgs) using rotary drilling equipment. A 14 inch diameter steel casing was installed to 240 ft bgs and screened from 80 to 95 ftbgs and from 210 to 235 ft bgs. Filter pack material of 6 12 sand was installed from 60 to 240 ft bgs. A sanitary seal of Portland cement was installed from 0 to 60 ft bgs. Due to deterioration of the steel casing, a steel repair swedge was installed from 78 to 82 ft bgs in 2004 by Don Pedro Pump. A 10 inch PVC casing liner was then installed within the 14 inch steel casing and the repair swedge. The 10 inch PVC casing was installed to 240 ft bgs and screened from 181 to 240 ftbgs. INVESTIGATION RESULTS On May 26, 2011, JJ&A personnel supervised the down hole video investigation of IN 1, by Welenco Water Well Technologies, Inc., of Bakersfield, California. All above ground piping and down hole equipment (e.g., pump) were removed prior to the investigation. A video survey of the inner 10 inch Revised Work Plan for IN 1 Destruction_Final_091311

3 Revised Work Plan for Supply Well IN 1 Destruction September 13, 2011 Page 2 of 6 PVC liner was performed to verify well construction. An inspection of the annulus between the 10 inch PVC casing and the 14 inch steel casing was not possible deeper than 42 ft bgs due to an obstruction. The presence of a 10 inch PVC casing within the 14 inch steel casing was confirmed during the field investigation. The screen interval of the inner 10 inch PVC casing begins at approximately 181 ft bgs. There is sediment filling the well casing at 233 ft bgs. The DWR Well Drillers Report lists a total depth of 240 ft bgs. The observed construction of the inner 10 inch PVC casing appeared consistent with the information listed on the repair log. A summary of reported well construction details and observations is provided on Figure 3 (Attachment 1). WELL DESTRUCTION APPROACH The destruction of IN 1 is complicated by: (1) the steel repair swedge and PVC casing that were installed inside the steel well in 2004, and (2) the location of the well within the operating area of the facility. Limitations imposed by the well construction and location on destruction options include the following. Mechanical Perforation and Pressure Grouting: traditional perforation technologies (such as a Mills Knife to cut the casing) cannot be used as the presence of the interior PVC casing precludes the ability to reach and perforate the original steel casing. Grouting will not be a successful means of destruction without the perforations as there must be a means of injecting the grout into the filter pack. PVC Casing Removal: removal of the PVC casing has been considered to allow access to the steel casing, however, the presence of the steel swedge and the potential structural collapse of the steel casing complicates the ability to drill and/or pull the PVC casing. Explosive Charges for Perforation and Cement Slurry Delivery: this approach was used successfully for the destruction of the HCC supply well IN 2. The sensitive nature of the facility equipment and piping in the vicinity of IN 1, however, creates the potential for damage to structures and piping by the explosive charge shock waves. Over Drilling: large diameter drill equipment would be necessary to core outside of the steel casing; this approach also has associated logistical complications for well access. The combination of the existing well condition, existing production equipment, and related piping and other appurtenances create a complicated set of conditions that must be addressed and assessed to ensure a successful and complete well destruction. Three California based drilling sub contractors were initially contacted in July 2011 to identify technically viable well destruction methods and a driller with the necessary expertise and abilities to destroy the well in a manner that would successfully addresses the specific well construction and location issues.

4 Revised Work Plan for Supply Well IN 1 Destruction September 13, 2011 Page 3 of 6 The responses were evaluated to determine if the proposed approach would meet the project objectives. Each of the technologies proposed carried a significant risk of failure, wherein the well destruction may not be achieved but the well would be damaged such that it could not be properly destroyed by other methods. The use of explosives as a means of perforating the well casing and grouting the well was identified as a potential alternative based on the success of this approach at IN 2; however, the potential for damage to facility structures and associated piping in the vicinity of IN 1 presented an unacceptable risk for the current facility operations. The exploration of well destruction options and the search for qualified drilling contractors was expanded and a Request for Proposal (RFP) was submitted on August 28, 2011 to an additional 10 largeequipment drilling contractors located across the United States. JJ&A received three proposals in response to this RFP; the other subcontractors declined to submit proposals. No new technologies or approaches were identified in the responses or in verbal communications with the contractors. We are continuing to reach out to experts in the field including professional organizations and drilling contractor s located through out North America. Based on a review of all proposals and technical discussions with experts in the field to date, we have developed the following phased approach. IN 1 DESTRUCTION METHOD ALTERNATIVES This section describes the phased approach developed by JJ&A to evaluate potentially viable technologies for the destruction of IN 1. This involves the process of evaluating well destruction technologies in a step wise fashion. It is important to note that the technologies attempted in the field will not preclude the use of the next alternative in the process. For example, a technology that could potentially prevent access to the interior of the well would not be attempted prior to a technology that required such access. Alternative 1: High Pressure Water Perforation and Pressure Grout The first technology to be evaluated will be high pressure water perforation. This method will be evaluated to verify if jets of very high pressure water, augmented with a garnet based cutting agent, can perforate both the 10 inch PVC and 14 inch steel casings in place at depth (i.e., below the water table). The high pressure water perforation will use 30,000 to 40,000 pounds per square inch (psi) and generate 4 to 6 gallons per minute (gpm). It is anticipated that the water generated through this process would be contained within the well; however, alternatives for water management would be developed and considered including a temporary holding tank. If this technology is able to make the appropriate perforations in both casings then the well casings will be thoroughly perforated and properly destroyed by standard pressure grouting techniques.

5 Revised Work Plan for Supply Well IN 1 Destruction September 13, 2011 Page 4 of 6 Alternative 2: Depth Discrete Blast Perforation with Explosives Supply well IN 1 is reportedly screened in both the Upper Aquifer (80 ft bgs to 95 ft bgs) and in the Lower Aquifer (181 ft bgs to 240 ft bgs). There is likely a downward gradient at this location, similar to IN 2, as reported in JJ&A s Lower Aquifer Source and Extent Evaluation Report (2011). The primary purpose of the well destruction is to remove the conduit for potentially preferential flow between the upper and lower aquifers. This objective can be accomplished by sealing the borehole at, and/or below, the Corcoran Clay layer. To evaluate the use of depth discrete explosives to destroy IN 1, a test hole will be installed across the Corcoran Clay (approximately 161 ft bgs) in the vicinity of MW 7, MW 11 and MW 18; with the exact location to be determined (See Figure 2 of Attachment 1 for well locations). This area was chosen as it is free of sensitive equipment and operations, has a similar sub surface condition and has a paved surface. Primacord (i.e., explosive cord) would be deployed within the well casing with explosive booster charges installed at 10 foot intervals starting at 110 ft bgs. The boring would then be filled with 10.3 sack sand cement slurry from the bottom to the top of the boring. The explosive charges would be detonated forcing the cement slurry into the formation. The magnitude of the shock will be measured using geophysical tools installed at the surface. If the magnitude of the shock waves measured at the surface are acceptable (i.e., it is determined that this approach will not damage equipment or piping proximal to IN 1) then this approach will be applied at IN 1. Primacord would be deployed within the IN 1 well casing with explosive booster charges installed at 10 foot intervals starting at 110 ft bgs. The casing would then be filled with 10.3 sack sand cement slurry from the bottom to the top of the well. Additional slurry will be pumped into the annular space between the casings. The explosive charges would then be detonated, perforating the well casing(s) and forcing the cement slurry into the annular pore space. If it is determined that the shock waves could result in damage to shallow subsurface and/or surface equipment or piping, the next step in the evaluation will be taken. Alternative 3: Drill Out PVC Casing, Mills Knife Steel Casing, and Pressure Grout Based on our investigation, there is very little space, if any, between sections of the PVC inner casing and the metal outer casing and/or repair swedge. Drilling out the interior PVC casing using down hole tools has the potential to contact this metal, twist and deform the metal thereby plugging the inner casing and preventing further access to the interior of the well. A down hole opener or other specialized rotary drill head will be used to drill out the 10 inch PVC casing. Following the removal of the 10 inch PVC casing, the 14 inch steel casing will be perforated using a Mills

6 Revised Work Plan for Supply Well IN 1 Destruction September 13, 2011 Page 5 of 6 Knife. Once the perforations are complete, the well will be properly destroyed by filling the well with Portland cement with a tremie pipe and pressure grouting. If an issue is encountered during the removal of the PVC casing or subsequent Mills Knife procedures, the next alternative will be evaluated. Alternative 4: Over drill with Wash Over Casing If the previously described technologies are not successful, an attempt will be made to over drill the well using a wash over casing with an inner diameter of 16 inches (or larger as available). 1 The well materials will be removed from the drill casing to total depth and the boring will be backfilled with grout. PERMITTING Prior to beginning work, a well destruction permit, and if applicable a boring permit, will be procured from the Merced County Department of Environmental Health, as required. All interested parties (including state and local regulatory agencies) will be kept apprised of all field activities and results. UTILITY SURVEYS The proposed well destruction location, and if applicable any boring locations, will be marked using white paint. Underground Service Alert (USA) will be contacted at least 48 hours prior to sub surface activities. An underground utility locating company will be utilized to delineate other potential buried utilities at the site, as needed. SCHEDULE Following approval by the RWQCB, JJ&A will immediately begin preparations to implement this scope of work. The schedule is constructed to allow for the field scale testing of each technology as appropriate. In some cases the time indicated is needed for the identification and procurement of specialty subcontractors of qualified subcontractors. The timeline proposed to complete the destruction of IN 1 is provided in the following table. PROPOSED IMPLEMENTATION SCHEDULE Alternative Description Schedule Alternative 1 High Pressure Water Perforation will be the first alternative evaluated. This evaluation includes field testing of the technology. 8 to 12 weeks 1 JJ&A has not been successful to date procuring a contractor with the required equipment; however we have discussed this method with drilling companies that have confirmed this equipment exists and has historically been available in California. We are continuing to reach out to the drilling community to identify a qualified subcontractor.

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8 ATTACHMENT 1 FIGURES

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12 ATTACHMENT 2 DWR WELL DRILLERS REPORT AND REPAIR NOTES

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