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The drilling subcontractor was Vironex, Inc., of Bowie, Maryland. The soil borings were drilled by the direct push technology (DPT, or “Geoprobe”) drilling method. With the DPT technique, a sampling barrel fitted with a 2-inch-diameter by 4-foot-long acetate core sleeve is hydraulically advanced (or pushed) into the subsurface to get a soil core. The barrel is withdrawn from the borehole, the acetate core sleeve is removed, a new core sleeve is inserted into the barrel, and therefore the sampling assembly is reinserted into the borehole to get the next core. The borehole stayed open when the sampling assembly was withdrawn owing to the clayey and silty nature of the soil. At each location, continuous soil samples or cores were collected from the bottom surface to the highest of bedrock (which was defined as hydraulic refusal, or the lack to additional advance the barrel). The depths of the two borings were 10 feet (01SB51) and eleven feet (01SB52). At the conclusion of each boring, the borehole was backfilled with a mix of soil cuttings and bentonite. The [http://www.denichsoiltest.com/field/soil-boring-rotary-drilling.html soil boring test] were surveyed for horizontal location and vertical elevation by James M. Stewart, Inc. Their survey knowledge are presented in Appendix A.