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GSI Mid-Atlantic

Tagged: Geoprobe Delaware

GSI is looking for the right person

Environmental Field Technician, Driller Helper, Driller

GSI Mid-Atlantic, Inc. provides specialized environmental drilling and direct-push sampling services to environmental consultants and engineers.

Looking for entry to mid-level person to assist with operation of direct push drilling equipment on environmental investigation and remediation sites. Position will work out of our Glen Burnie and White Marsh yards. Must be reliable, have good work ethic and be customer service oriented.

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GSI Adds Low Clearance Limited Access Capabilities

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GSI Mid-Atlantic, Inc. has added a Geoprobe 54lt to it’s fleet. The 54lt is a capable limited access and low clearance machine. The machine will fit through a standard 36″ doorway allowing access to inside most buildings, as well as through small fence openings and other narrow previously inaccessible areas. ¬†Our 54lt is equipped with a low clearance probe cylinder that allows the machine to operate with under 8′ of overhead clearance, perfect for low parking garages and inside of buildings.

Don Marchese adds Delaware License to his Resume

Congratulation to Don Marchese, GSI, for obtaining his Delaware well driller license. The addition will provide essential support for GSI’s increasing workload in Delaware.

Drilling Deep In Delaware (Deep water sampling and prepack well installation)

GSI recently completed a scope of work in Delaware that included water sampling to 100′ below ground surface (BGS) and installation of prepack monitoring wells to 75′ BGS. The scope was follow-up sampling to fill data gaps from previous investigations GSI has assisted with at the same site.

The initial task consisted of vertical profiling at three locations by collecting a grab water sample from every 10′ to a depth of 100 feet. Static water level was between 6 and 8 feet. GSI utilized the Geoprobe Screen Point sampler(SP16). GSI used one of their Geoprobe 7822 machines to drive the closed SP16 sampler to the 100′ depth and then exposed the stainless sample screen. A peristaltic pump was used to purge the interval until the groundwater ran clear. Once the sample was collected the SP16 was pulled up 10′ to the next interval and again purged to remove water from the previous interval and produce clear formation water for a sample. This process was repeated until a sample from the shallow 6 to 10′ interval was collected. The three 100′ borings were completed on schedule in 1 1/2 days.

The next task consisted of installing nine (9) 1 1/2-inch prepack wells ranging from 45′ to 75′, with five of the nine specified for the 70 to 75′ range. Continuous soil cores were collected from each of the five deep well locations for logging the lithology. The more shallow wells were nested with a deep well and installed by driving closed casing to the target depth (45′-55′). Each well was completed with 10-foot prepack well screen and a 2-foot bentonite sleeve. Wells were then sealed with cement-bentonite grout placed through the drill casing . By grouting through the casing, GSI could be sure the wells were continuously sealed throughout the entire borehole. Wells were finished with flush mount covers and pumped for development. All wells were completed on schedule in about 5 days.

The photo below shows grouting the prepack wells through the casing and collection of the displaced water.

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GSI Uses Geoprobe DT45 for Monitoring Well Installation on DNREC Sites

GSI Mid-Atlantic, Inc. recently completed monitoring well installation on two DNREC sites using the Geoprobe 4.5″ dual tube system (DT45).

The first site was a former waste site along the Delaware Bay. The scope of work consisted of installing 6 shallow piezometers, 3 along each side of a remediation trench, and 2 deeper (20′) monitoring wells. All wells were specified to be 1.5″ diameter conventional PVC monitoring wells. The challenges of the site included extremely shallow water table (2 to 3′ BGS) and several feet of large gravel in some areas. GSI determined that the DT45 system would provide enough annular space with the 1.5″ casing to install the sand pack and bentonite seal through the annular space inside the DT45 casing. This would ensure a good sand pack and well seal despite the challenges of the shallow water and collapsing gravel. All 6 piezometers and the 2 monitoring wells were installed in 2 days.

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The second site, also a former waste site, was follow-up to a previous Geoprobe investigation. The scope of work called for installation of five 2-inch diameter standard monitoring wells. GSI again utilized the Geoprobe DT45 system. Use of an oversize cutting shoe created a nominal 6″ diameter bore-hole, which provides the 2″ annular space required for a standard built 2″ diameter monitoring well. Using the DT45 system allowed the wells to be installed using direct-push, rather than conventional hollow-stem auger. This created a significant savings on time and generation of investigation derived waste. All five wells were installed and developed in 2 days.

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Nice views of National Harbor

Recent job site with nice views of National Harbor!

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