WORK PLANS - Laserfiche WebLink

Home Browse Search

k'■ KLEtNFELDER The following is a summary of analytical results from soil samples collected on September 30, 2005 during the bellhole excavation by Line 401: tPG&E Line 401 Soil Sampling Results Sample Sample TPH-G TPH-D TPG-0 B T E X ID Depth (mg/kg) (mg/kg) (mg/kg) (µg/kg) (µg/kg) (µg/kg) (µg/kg) (feet) 1 BH 7'01- 7 4700 1,700 2,600 8,700 3,800 12,000 72,000 7' BHL401- 10 ND (<5) ND (<10) ND (<1) 29 ND (<5) 7.0 21 ' 10' Notes: BHL401 bellhole Line 401 TPH-G total petroleum hydrocarbons as referenced to gasoline TPH-D total petroleum hydrocarbons as referenced to diesel TPH-O total petroleum hydrocarbons as referenced to oil BTEX benzene, toluene, ethylbenze, total xylenes mg/kg milligrams per kilogram (parts per million) µg/kg micrograms per kilogram (parts per billion) Based on PG&E comments, during excavation of Line 401 there will be a need to slope the soil 1 to 1 with three feet excavated on each side of the pipe. PG&E has forwarded a 1 backfill specification guideline which has been forwarded to the excavation contractor Pacific States, including other technical information from PG&E. Backfilling will be conducted under PG&E oversight as per PG&E general guidelines. PG&E has indicated backfill beneath their pipes can be jetted or washed beneath their pipe with mechanical compaction along the sides of the pipe in 12 to 18 inch lifts. PG&E has indicated that Line 401 can span 150 feet, unsupported, safely. It will be up to the contractor to decide what intervals to expose Line 401 within this safety specification. Kleinfelder anticipates the pipe will need to be excavated in sections, and each section backfilled prior to excavation of the next section of pipe. A sample of the backfill material is requested to be submitted to PG&E for testing for their criteria. Kleinfelder anticipates import material can be obtained from a local supplier. It will be the excavation contractors responsibility to conduct the work according to OSHA guidelines and PG&E specifications. Final removal of soil in and around the PG&E pipeline will be directed by PG&E personnel. Kleinfelder will collected confirmation soil samples as directed by PG&E and as necessary. Kleinfelder however, is not providing oversight to the general contractor. PG&E has indicated that soil samples should be screened using a photo-ionization detector (PID). A clean-up goal of 100 parts per million using a PID has been tentatively proposed by PG&E during removal of soil around Line 401. Confirmation Soil Sampling Kleinfelder proposes collection of approximately thirty (30) discrete bottom excavation soil samples based on a 50 foot grid pattern. Kleinfelder estimates the average depths outside of the pipeline easement areas to be approximately 5 to 13 feet bgs as shown 44843.T04/STO5R1333/DH:ly Page 7 of 17 ©2005 Kleinfelder, Inc. October 25,2005