2600 FEDERAL AVE KIMBERLY CLARK Geotech Report 2022-10-25

May 25, 2017 HWA Project No. 2015-104-21 observed by Bob Hanford, from Aspect Engineering, Bryan Lust from Kimberly-Clark, Andy Kallus, from the Department of Ecology, and Project Owner Representative, Steve Abernathy. Monolith We understand this structure was encountered by the remediation crew on the southern extent of the excavation and replacement work performed in 2013-2014. According to Bryan Lust, the crew had encountered a concrete wall that extended below the depth of their remediation limit. They did not excavate laterally to determine the lateral extent of the structure. Bryan remembered the structure beginning at approximately 6 or 7 feet below the ground surface. During our excavation, the top of the structure (foundation stem wall) was located at 2.5 feet. We moved the excavation 30 feet to the west, and encountered a similar -trending structure again at 2.2 feet. The trench was then dug laterally along the structure to the west until the trench was 2 feet from monitoring well UST-71 MW-103. The trench was resumed 2 feet beyond the monitoring well, and the structure was again located at approximately 2.2 feet below the surface. We are unsure how the monitoring well was installed without hitting this obstruction during drilling. The excavator was moved another 50 feet to the west, where another similar -trending structure was encountered at 2.0 feet. This structure is assumed to be the northern foundation for the Repair Shop, Lime Storage, and Bleach Liquor Building. The distance between the easternmost and westernmost excavations was approximately 105 feet. The foundation wall may have a spread footing; and the remedial excavation encountered the sidewall of the footing, whereas our excavation may have been along the face of the stem wall above the foundation. Excavations were limited to a depth of 7 feet, and there was approximately 2.2 feet of concrete rubble in the area, so we were unable to confirm the structure that had been found previously, which would have been at 8 to 9 feet. Below the existing ground surface. Sheet Pile Wall The limits of the surface expression of this structure are shown on Figure 1. The north -south trending structure was encountered at the surface during the demolition project. Bryan Lust recalled that the excavation crew attempted to pull the sheet piles out but were unsuccessful., so the piles were cut down the ground surface. We could visually locate the southern terminus of the wall. The excavator was used to dig down approximately 6 feet to the south of the last pile observed, to ensure that the terminus had been located. We then excavated small potholes to the north to find the northern extent of the wall. The total wall length determined in the field was approximately 84 feet. Boiler Tank Saddles To increase the chances of encountering the tank saddle structures, the excavation was oriented east -west. Total trench length during excavation was approximately 20 feet. Structures were located at a depth of 3.0 feet. The structures consisted of concrete reinforced with rebar, and 5 to Technical Memorandum HWA GeoSciences Inc.