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R/W No.: EV00172 <br />Form B <br />EVERETT LINK EXTENSION Form Approved by Civil 9/24/19 <br />Form Approved by Legal 3/17/22 <br />Last saved by Anna Larson on 09/27/2024 <br />Attachment A – Definitions of Work <br />Geotechnical Exploration <br />To support the design, boreholes are needed to analyze the soil and it may be necessary to monitor the groundwater with a <br />piezometer. Typically, borehole work is performed as follows: The borehole will be approximately 6 to 8 inches in diameter. <br />The drilling will be completed using a truck-mounted hollow stem auger, a mud rotary drilling equipment, or a sonic core drill <br />rig. Vehicles on the site during the drilling will include the drill rig, a vactor truck, and a support vehicles for technical staff. <br />The work area will be approximately 15 feet wide by 70 feet long and can be reconfigured based on available space. The work <br />can usually be completed within three to five days, based on depth of boring and/or any work restrictions. The borehole will be <br />backfilled according to Washington State Department of Ecology regulations using bentonite chips or a bentonite-grout mixture. <br />After backfilling, the ground surface will be restored to the extent practical to the pre-drilled condition at the completion of the <br />borehole using compost and grass seed. If the borehole is located on pavement, a cold patch will be used to restore the area. <br />After the borehole is completed, a Civil Survey will be conducted which will include surveying the borehole. A typical crew <br />will consist of 2 or 3 individuals during the drilling operations. <br />If a piezometer is installed, a staff person will periodically (quarterly or semi-annually) visit the site for approximately 30 <br />minutes to download the data and to replace the batteries for the datalogger.