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+ Limited Subsurface Site investigation Results Report
<br /> Moore Petroleum Bulk Plant,5491 F Street,Banta,San Joaquin County,California
<br /> Page 2
<br /> well MW-1. The system was started on May 5, 1995, and operated through October 4, 1995, at
<br /> which time it was temporarily removed from the site. On November 27, 1995, the system was
<br /> returned to the subject site and restarted.
<br /> May 31, 1995 - An air sparge system was installed and started; this was used in conjunction with
<br /> the SVE system. The air sparge system operated intermittently through August 30, 1995, at
<br /> which time its operation began to coincide with the operation of the R.S.I. system. The air sparge
<br /> system consisted of a one horsepower electric motor which powers a 10-cubic feet per minute
<br /> (cfrn) oil-less compressor. The compressor injected air through an air sparge point located
<br /> midway between VEW-1 and MW-1.
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<br /> April 29, 1997 - Apex received permission from the SJCEHD to shut down the air sparge and
<br /> vapor-extraction system due to low influent soil vapor concentrations. As of April 29, 1997, the
<br /> remediation system had extracted a total of 1,730 pounds of total petroleum hydrocarbons as
<br /> gasoline (TPHg), and 19.9 pounds of benzene.
<br /> September 10, 1997 - Apex submitted the report titled, Over Excavation & Groundwater
<br /> Removal Workplan, proposing over excavation, de-watering and sampling of the bulk loading
<br /> rack and tank basins during the removal of nine underground storage tanks (UST).
<br /> August 17, 1998 and September 8, 1998 - Apex supervised the removal of two 350 gallon USTs,
<br /> T-8 and T-9 (kerosene and cleaning solvent, respectively). Also, seven 10,000-gallon USTs were
<br /> removed on September 8, 1998. Following the removal of T-9, soil was over excavated and an
<br /> exploratory trench was dug. Apex collected two soil samples and one groundwater sample from
<br /> the over-excavation and exploratory trench. One soil sample was collected from beneath T-8.
<br /> After the removal of the seven 10,000-gallon USTs, Apex collected four soil samples and one
<br /> groundwater sample from the tank pit. Apex then collected six soil samples and two water
<br /> samples from beneath the tank basin. Nine soil samples from the area beneath the former bulk
<br /> loading rack were submitted for analysis. The results of all soil and water sampling were
<br /> documented in Tank Closure Results and Recommendations Report, dated December 23, 1998.
<br /> April 8 - 9, 1999 - Apex personnel supervised the advancement of eight soil borings at the
<br /> subject property. The results of all soil and water sampling were documented in Results Report
<br /> for Subsurface Investigation and Second Quarter 1999 Groundwater Monitoring, dated June 1,
<br /> 1999,
<br /> August 6, 1999 - Apex submitted Workplan for Limited Subsurface Investigation, proposing the
<br /> installation of four additional groundwater monitoring wells (MW-4A, MW-7, MW-8, and MW-
<br /> 9). During installation, well MW-8 was installed with the screen and filter pack extending into
<br /> the unsaturated zone for possible future use as a vapor extraction well. In addition, underground
<br /> piping was installed from well MW-8 (VEW-3) to the former remediation compound.
<br /> April 27, 2000 - Apex submitted Workplan for Limited Subsurface Investigation, proposing the
<br /> installation of three additional groundwater monitoring wells and one deep soil boring.
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