| Project |
Client |
Photos (click to see full size) |
Description |
|
Crosshole
Seismic Tomography
|
Warren
George
|
 |
HGI has
added crosshole seismic tomography to its arsenal. Using an
energy capacitor, sparker, hydrophones, and remote trigger, HGI can
characterize bedrock fractures, changes in lithology, and
contamination between boreholes. TOMTIME® and GEOTOM CG® are
used for data analysis. HGI recently used seismic tomography
to map bedrock fractures between well pairs in Manhattan, New York,
for the 2nd
Avenue Subway Project. The remote trigger was particularly
useful for communication between the sparker and hydrophones when
boreholes were on opposite sides of the street. |
|
Boring Clearance and Location of UST's
and Utilities
|
Jeter
Cook Jepson
|
 |
HGI
has been performing geophysical surveys for environmental investigations
related to construction projects to locate USTs, utilities, and
subsurface obstructions. These surveys have been performed for
borehole clearance as well as entire sites many acres in
size. Surveys
are performed using GPR and/or EM, often in combination with
a pipe and cable locator. Results are marked in the field and
presented as CAD plots showing the location of targets. |
|
Concrete Scan
|
Honeywell
|
 |
HGI
used the Structure Scan II® system to assess concrete integrity and
reinforcement patterns of a concrete ringwall. A
series of grids were appended in Radan
NT 4.0® to produce a 3D model. The results were displayed
as videos with voice-over for each quarter of the ringwall. |
|
3D Utility Survey
|
Manafort Bros.
|
 |
HGI
performed a ground penetrating radar survey to locate known and
unknown utilities. These utilities were mapped out in a 3D
format using GSSI's Radan program. The 3D images were used to create a
clearer view of where the utilities were relative to each other in
terms of position and depth. |
|
Borehole Geophysical Surveys
|
TTNUS
|
 |
HGI
performed borehole logging as well as surface geophysical surveys
at an EPA site in Rhode Island. The purpose of the logging was to
locate bedrock fractures and determine their orientation (strike
and dip), as well as the location and rate of water inflow. To
accomplish these goals, HGI's logging suite included caliper,
natural gamma, heat pulse flowmeter (HPFM), and acoustic televiewer
(ATV) logging in five boreholes.Click to view image
#2 or
image
#3. |
|
Mapping Migration Pathways at Brunswick Naval Air Station
|
Gannett Fleming
|
 |
A multidisciplinary
geophysical study was performed at Naval Air Station, Brunswick, Maine.
The goal of the study was to provide a better understanding of the possible migration
pathways of the contaminants in bedrock fractures and deeper stratigraphic zones
whose geometries might be controlled by bedrock morphology. The scope of work
consisted of mapping the bedrock surface, identifying and locating fracture zones,
and mapping the continuity and extent of key stratigraphic horizons. Seismic refraction
and reflection, GPR, and
resistivity were used to meet the study goals. |
|
Dam
Cutoff Wall GPR Survey
|
Treviicos/Rodio
JV
|
 |
GPR was used at a dam rehabilitation
drill site to assess the extent of a metal obstruction within limestone bedrock beneath almost 100
feet of water. The survey was designed for an underwater investigation on the lake bottom using the
Tubewave-100 borehole radar. Work was performed from a mini-tug, with the antenna dragged along the
lake bottom. Additional investigations were conducted in the same manner to locate rebar in concrete
structures. Click to view a GPR cross-section. |
|
Geological Services for Combined Sewer
Overflow Project
|
Gilbane-Jacobs
Joint Venture
|
 |
HGI is
working on an ongoing multi-faceted project for a metropolitan
combined sewer overflow. HGI is charged with monitoring the
blast vibrations in sensitive locales using both seismographs
and hydrophones. In addition to this monitoring HGI creates
bedrock maps
of the tunnel systems
created by blasting or by a tunnel boring machine (TBM).
|
|
Archaelogical Survey at 18th Century
Site
|
National Park Service
|
 |
HGI
used EM terrain conductivity and ground penetrating radar to locate
potential archaeological targets in Minute Man National Historical Park. The survey
area consisted of several separate parcels, and encompasses
much of the setting for the “shot heard around the world,” the
opening hostilities between the British Regulars and American
militiamen leading up the American Revolution. Click to view an EM
map view or a
GPR cross-section.
GSSI's Radan was used to create a 3D horizontal slice
to better show the location of the grave. |
|
Geophysical
Methods for Mineral Exploration
|
Confidential Client
|
 |
MASW and GPR methods were
used as exploration techniques to locate potential mineral deposits within a geologic setting
of highly deformed metamorphic rocks overlain by lateritic soil horizons. A 24-channel
land streamer system was used to profile overlying lateritic horizons and bedrock
up to depths of 100 feet. MASW survey geometry was optimized for fepths up to 60 feet and high
horizontal resolution. High-powered 100-MHz bi-static antennas were used to collect data along
seismic lines as well as in areas unsuitable for the
MASW method. Click to view
a GPR cross-section
. |
