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• • The email from the LEA is asking AGE if they have trench logs for the work conducted. (39 AS t0the �EAgG-CR-i� j, 1114 rp,., + This email from AGE states that the area of waste "handling" is well defined by historical photos and the current"set of trench "logs" and additional trenching would be outside the areas already investigated. AGE states that north is a leve[e]I built for a flood, south is pasture land, west is the property line and power plant and east is [a] ditch with trees. They stated that the area which is covered represents the glass "management area and disposal area" maps attached. AGE referred to the attached draft trench log for the site in Lathrop and that finding of glass or debris are noted; otherwise the content of the trenches consisted of tan to brown sandy loam soil or silty loam soil, without discoloration. AGE stated that a "photo for location at Trench 11 had a thin glass cement, otherwise mostly soil cover and native." AGE said that if an inspection was required that they would be able to conduct one anytime and that it may be critical to have CalRecycle inspect for verification. Comments: What is meant by a "thin glass cement, otherwise mostly soil cover and native?" Trench logs should be submitted documenting field observations at individual locations, including the presence/absence of wastes, waste depths when present, indicating whether native soils were encountered, presence/absence of cover, and sample locations/depths. A figure should also be provided summarizing findings of the trenches. It appears that although exploratory trenching was conducted at the "waste handling" area, that based on historical aerial photographs and background information that wastes extend beyond the area that was the location of the exploratory trenches/site investigation. Draft documents typically are not submitted to regulatory agencies since these agencies typically require signed reports/documents/letter prior to their review. (An excel table of trench logs was provided as a separate document to be reviewed and may be the draft trench log.) Jtifie.3,X2015 This email response from the LEA shortly after the AGE email (above) states that it is important to remember that well defined by ones definition maybe different to someone else. Currently, CalRecycle is not so certain that i[t]s has been well defined. The LEA suggested that ground penetrating radar [GPR] be used to give a better picture and rule out any other waste that may be onsite. The LEA stated that CalRecycle was receptive to this. Comments: Typically GPR is used prior to conducting a waste disposal site investigation to assist with locating exploratory trenches to delineate the extent of wastes (as opposed to after field investigation work is conducted). Historical aerial photographs as well as background documents as early as the 1980s provide information on the suspected extent of waste disposal and about the estimated volume of wastes disposed of. Based on this information available at the time, it appears that wastes were disposed of at locations outlying the area that was investigated and that the extent of wastes was not delineated. Information to confirm that the extent of wastes on the property was delineated was not provided. Ninyo&Moore 1 500 E.Louise Avenue,Lathrop,San Joaquin County,California 1 104690095 1 August 11,2017 31