- Home
- Conferences
- Conference Proceedings
- Conferences
10th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems
- Conference date: 23 Mar 1997 - 26 Mar 1997
- Location: Reno, Nevada, USA
- Published: 23 March 1997
1 - 20 of 106 results
-
-
History Of Geophysical Studies At The Waste Isolation Pilot Plant (Wipp), Southeastern New Mexico*
More LessA variety of geophysical methods including the spectrum of seismic, electrical, electromagnetic and potential field
techniques have used support characterization, monitoring and experimental studies at the Waste Isolation Pilot
Plant (WIPP). The geophysical studies have provided significant understanding of the nature of site deformation,
tectonics and stability. Geophysical methods have delineated possible brine reservoirs beneath the underground
facility and have defined the disturbed rock zone that forms around underground excavations. The role of
geophysics in the WIPP project has evolved with the project. The early uses were for site characterization to satisfy
site selection criteria or factors. As the regulatory framework for WIPP grew since 1980, the geophysics program
was focused on support of experimental and field programs such as Salado hydrogeology and underground room
systems and excavations. In summary, the major types of issues that geophysical studies addressed for WIPP are:
l Issue I: Site Characterization
l Issue 2: Castile Brine Reservoirs
l Issue 3: Rustler /Dewey Lake Hydrogeology
l Issue 4: Salado Hydrogeology
l Issue 5: Excavation Effects
The nature of geophysics program for WIPP has been to support investigation rather than being the principal
investigation itself The geophysics program has been used to define conceptual models (e.g., the Disturbed Rock
Zone-DRZ) or to test conceptual models (e.g., high transmissivity zones in the Rustler Formation). An effect of
being a support program is that as new project priorities arose the funding for the geophysics program was limited
and withdrawn. An outcome is that much of the geophysics survey information resides in contractor reports since
final interpretation reports were not funded.
*This work was supported by the United States Department of Energy under contract DE-AC04-94AL85000
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company for the United Sates Department of Energy
-
-
-
Electrical Resistivity Monitoring Of The Thermomechanical Heater Test In Yucca Mountain
Authors A. Ramirez, W. Daily, M. Buettner and D. LaBrecqueA test is being conducted in the densely welded Jopopah Springs tuff
within Yucca Mountain, Nevada to study the thermomechanical and
hydrological behavior of this horizon when it is headed. A single 4 kW heater,
placed in a horizontal borehole, was turned on August, 1996 and will continue
to heat the rockmass until April 1997. Of the several thermal, mechanical and
hydrological measurements being used to monitor the rockmass response,
electrical resistance tomography (ERT) is being used to monitor the movement
of liquid water with a special interest in the movement of condensate out of the
system. Four boreholes, containing a total of 30 ERT electrodes, were drilled to
form the sides of a 30 foot square with the heater at the center and
perpendicular to the plane. Images of resistivity change were calculated using
data collected before and during the heating episode. The changes recovered
show a region of decreasing resistivity approximately centered around the
heater. The size this region grows with time and the resistivity decreases
become stronger. The changes in resistivity are caused by both temperature
and saturation changes. The observed resistivity changes suggest that the rock
adjacent to the heater dries as heating progresses. This dry region is
surrounded by a region of increased saturation where steam recondenses and
imbibes into the rock.
-
-
-
Test Results Of Cpt-Deployed Vertical Electrode Arrays At The Doe Hanford Site
Authors S.M. Narbutovskih, W. Daily, A.L. Ramirez and R.M. MoreyField studies were conducted at the DOE Hanford Site to test cone penetrometer installation of
vertical electrode arrays (VEA) for use with Electrical Resistivity Tomography (ERT). Most
VEA installation methods in current use are not economic for environmental applications. The
cone penetrometer technology (CPT) can provide an economic and relatively non-intrusive
installation method. However, a VEA with deployable and properly functioning electrodes was
required. Results of the design, installation and testing of CPT VEAs are reported in this paper.
Several designs were developed and bench tested for use with the CPT. After initial field
installation studies, one design was chosen for further testing at the DOE Hanford Site. Four
VEAs were each pushed to 100 feet in 4 days. To test the CPT VEAs, an infiltration experiment
was conducted with cross VEA tomographic data collected for three vertical planes. These data
were processed using the electrical resistivity tomography code developed by Lawrence
I,ivermore National Laboratory (LLNL). Tomographic images for each vertical plane tracked
the subsurface resistivity changes associated with the migrating fluid.
It is concluded from these test results that the CPT is a viable method for installing VEAs. The
VEAs were rapidly and economically installed to the maximum depth required, data of adequate
quality were obtained and tomographic images from the infiltration experiment verified that the
CPT VEAs provide viable ERT data.
-
-
-
Focusing Transformations - The Reliable Way To Search For Safe Location For Nuclear Waste Disposal
Authors V.A. Pozdniakov, V.A. Tcheverda and D.V. SafonovAt present pre-stack migration is widely used in seismic data processing in order to get wave image of
a medium under investigation. Of course it is rather time-consuming procedure but its application is
justified by necessity to deal with complicated geological structures and to recover them as completely
as possible. The paper is devoted to the approach to pre-stack migration of multicoverage seismic data
by means of diffraction and focusing transformation in application to the problem of careful geological
investigation of consolidated rocky blocks in order to choose as safety as possible location of nuclear waste
deposit. Results of some real seismic data processing gathered at Nijnekanskaja area near Krasnoyarsk
city, where a granite block is searching for as a suitable candidate for disposal of radioactive waste, are
presented and discussed.
-
-
-
Locating Buried Trenches Using An Integrated Geophysical Study At The Parks Shallow Land Disposal Area
Authors Robert J. Withers, John E. Scaife and Steffan HelbigAt the Parks site, Western Pennsylvania, a geophysical survey was undertaken to
determine the size and location of buried trenches containing radiological waste. Several
geophysical techniques were used to non-intrusively locate the trench boundaries. The
trenches outlines could be mapped from surface conductivity profiles. Magnetometer
surveys identified much of the ferrous material buried within the trenches, and further
defined the location of the trenches.
Several vintages of ground penetrating radar were used, with the need for low frequency
antenna demonstrated by testing. A 50 MHz GPR antenna was elected for a series of
profiles across the trenches. By integrating interpretations from the total magnetic field,
magnetic gradients, conductivity data and radar profiles it was possible to provide an
accurate map of the trenches verified by subsequent drilling. Seismic and microgravity
techniques were not able to verify the location of mine workings beneath the area of
investigation.
-
-
-
Practical Geophysical Applications For Everyday Operational And Engineering Problems At Newmont Gold Company
Authors Kevin Freeman, Jim Wright and Nigel PhillipsNewmont Exploration Limited’s Carlin based geophysics team primarily concerns itself with
gold exploration along the 101 Moz Carlin Trend. While most of this activity takes place off the
mine sites, occasions arise where the team is called upon or recognizes an opportunity to perform
tasks for mine operations and engineering.
Various electrical and potential field methods have been used in different applications with
mixed results. Past efforts have included electrical potential mapping for leak detection in leach
solution collection ponds and bio-leach culture tanks; time domain EM was utilized in leach pad
solution saturation studies; and highly detailed gravity has been used in void detection in the
Rain Pit. Brief case histories of each of these are presented. Included are logistical scenarios and
methodology of select applications and their results.
Results of past geophysical efforts by NEL have proved highly successful, resulting in quick,
inexpensive, and definitive answers for mine operations and engineering problems.
-
-
-
The Development And Testing Of A Geophysical Blast Movement Measurement Technique For Surface Mines
Authors Geraint W. Harris, Pierre Mousset-Jones, Jaak Daemen and Robert KarlinIn order to minimize the ore dilution induced by blast movement in surface mines it is necessary to quantify
such movement. This will make it possible to more accurately locate the grade boundaries on the surface of a
blasted rockpile prior to excavation. This paper describes the development and testing of a method to accurately
measure the direction and magnitude of sub-surface blast movement. The technique involves the use of magnetic
gradiometry, using a cesium vapor gradiometer and real-time differentially corrected, GPS system, to locate the
post-blast position of magnetically enhanced target objects, whose pre-blast locations are known, without
disturbance of the blasted rock. The objective is to design an accurate and eflicient technique which can be
integrated into a mine’s production cycle.
-
-
-
Case Histories Of Electrical And Electromagnetic Geophysics For Environmental Applications At Active Mines
Authors Norman R. Carlson and Kenneth L. ZongeAlthough some aspects of the environmental service industry appear to be leveling off or
declining, as a contractor primarily serving the minerals exploration industry, we continue to see
a slow but steady increase in the use of geophysics for enviromnental and engineering problems
at active mines. We attribute this to several factors. One reason is that mine geologists and
engineers are typically more familiar with geophysics (its applications and limitations) than
many of our environmental clients, and they are more familiar with a broader range of
geophysics. Other important factors are the technological advances (both hardware and
software) that allow data acquisition in mine enviromnents that were once too noisy or
complicated. In this paper, we discuss several examples of environmental and engineering
projects at active mines, with an emphasis on how these projects differ from our “normal”
enviromnental projects.
-
-
-
Tests Of Ground Penetrating Radar And Induced Polarization For Mapping Flwial Mine Tailings On The Floor Of Coeur D’Alene River, Idaho
In order to investigate sequences of mine tailings that have settled in the bed of the Coeur
d’Alene River, we improvised ways to make geophysical measurements on the river floor. To
make ground penetrating radar (GPR) profiles, we mounted borehole antennas on a skid that was
towed along the river bottom. To make induced polarization (IP) profiles, we devised a bottom
streamer from a garden hose, Pb strips, and insulated wire. Both expedients worked well. GPR
showed shallow stratigraphy, but did not directly detect the presence of contaminating metals. IP
showed a zone of high chargeability that is probably due to pockets of relatively higher metal
content. Neither method was able to define the base of the fluvial tailings section.
-
-
-
Downhole Ip Measurements Ulth A Piezocone At Mine Tailings Impoundment
Authors H. Kristiansen, R.G. Campanella, M.P. Davies and C. DanielThe last decade’s environmental concerns have resulted in additions to the Cone
Penetration Test piezocone making it capable of measuring geophysical parameters and therefore
effective at identifying anomalies. This paper describes one of the most recently developed
additions, which measures the induced polarization (IP) effects.
The testing site used to assess the capability of the IP-piezocone consisted of very
conductive mine tailings impoundments. The piezocone was used to study the detailed
stratigraphy, measure hydrogeological and geotechnical parameters and therefore provided
ground truthing.
The IP measuring system is described in detail. A typical IP trace is presented and
discussed in combination with the resistivity piezocone profiles and parameters.
Factors affecting results and application of IP measured with the piezocone are discussed.
-
-
-
Surface And Downhole Em Investigations At Potash Mine Sites In Saskatchewan, Canada: Case Histories
Authors G. Phillips and H. MaathuisWaste products from the potash industry in Saskatchewan are stored in surface tailings
management areas (TMA) which commonly consist of a salt tailings pile and a brine pond,
surrounded by dykes. Because the fluid level within the TMA is higher than its surrounding, and
because of density effects, surface brine migration occurs in varying degrees.
The high electrical conductivity of the brine compared to normal groundwater make geo-electrical
methods well suited to measure and monitor both lateral and vertical brine migration originating
from TMA’s. Historically, shallow lateral brine migration was measured by monitor wells or soil extract
analyses, but in recent years surface EM measurements increasingly have been used for mapping,
and for monitoring of the rate of migration and impact of remedial measures.
Vertical brine migration occurs both within the TMA as well as outside the perimeter dykes, in
areas affected by shallow lateral brine migration. In the past, detailed data on vertical brine
migration could only be obtained by means of soil extract data. Downhole EM measurements
have shown that vertical brine migration occurs typically to depths of 5 to 10 m. The transition
zone from full brine concentration to background values commonly is in the order of 2 to 3 rn,
consistent with diffusion-controlled vertical brine migration.
-
-
-
The Use Of Geophysical Methods For Assessment Of The Fracture Process Due To Mining Subsidence
More LessThe space distribution and time advance of subsidence of rock overburden in exploited
areas depends on the volume and shape of the exploited area.
Three causes of subsidence are discussed in the paper; tunnels with elliptical crosssection,
upward moving elongated disturbance of rock properties, and exploited areas beyond
long-wall exploitation. In each case, seismic and geoelectric methods may be used to assess
the fracture zone shape and location or predict the appearance of fracturing.
-
-
-
Seismic Mapping Of An Abandoned Lead-Zinc Mine, Joplin, Missouri
More LessIn the mining of lead and zinc in the Joplin Missouri area, the open-pit method of mining was used if the ore extended
close to the surface or following the collapse of the underground operations. A regional hospital in Joplin Missouri
owns property in this mining region that in places overlies an infilled and abandoned open-pit lead-zinc mine. Much
of the infilled pit area has been covered by asphalt and is currently used as an open parking lot (about 62,500 ff). The
southern edge of the parking lot abuts a wing of the hospital complex; the eastern edge abuts a multi-storied parking
facility.
The hospital administration is considering erecting a multi-storied annex to the hospital wing on the asphalt parking lot
site. Recent subsidence of the asphalt paving occurred in parts of the parking lot which did not correlate with existing
maps that outlined the old open-pit mine location. To obtain a more detailed structural control at bedrock level, drilling
to bedrock and the acquisition of 25 parallel high-resolution reflection seismic profiles were undertaken. On the seismic
data, the bedrock reflector can be interpreted and spatially mapped across the parking lot from one line to the next. The
interpretation of the reflection seismic data was constrained and validated by the test boreholes within the parking lot
area.
This case study is presented as an example of the utility of the seismic technique for mapping bedrock in a structurally
complex area, and in a noisy urban environment with adverse surface conditions.
-
-
-
Reflection Seismic Mapping Of An Abandoned Coal Mine, Belleville, Illinois
Authors Neil Anderson, Ronald Hinds, Doug Lambert, Mike Roark, Mike Shoemaker and Jesse BakerOld mine location maps (1958 vintage) indicate that the northwestern part of an undeveloped property near the town of
Belleville, St. Clair County, Illinois, is situated above an abandoned and now water-filled, room-and-pillar type coal mine.
The central and southeast parts of the Belleville property are shown as overlying intact (non-mined) coal. The coal unit
mined at the Belleville site, the Herrin #6 is Pennsylvanian in age and about 2.5 m thick at a depth of around 40 m.
The current owners of the BelleviIle property want to construct a large building on the central and southeast parts of the site,
but have been concerned about the accuracy of the old mine location maps because of recent mine-related surface subsidence
in areas designated on the maps as not mined. To ensure that the proposed new development is located on structurally stable
ground, a grid of ten high-resolution reflection seismic lines was acquired on-site. On these reflection seismic data, minedout
areas can be visually identitied and d&rentiated Tom non-mined areas. The interpretation of the reflection seismic data
was constrained and validated by 15 test boreholes. These seismic and borehole data confirm that the central and southeast
parts of the property have not been mined extensively. Development of the Belleville site has proceeded with confidence.
-
-
-
Seismic Exploration For Cretaceous Kaolin Deposits In Glaciated Terrains: Example From Nova Scotia, Canada
Authors S.E. Pullan, R.R. Stea, P.W. Finck, R.A. Bums, M. Douma and R.L. GoodThe Geological Survey of Canada and the Nova Scotia Department of Natural Resources have
recently completed a joint project which has led to a major discovery of commercially viable
deposits of kaolin in the Shubenacadie and Musquodoboit Valleys in central Nova Scotia. The aim
of the project was to delineate the three-dimensional distribution of Cretaceous and Quatemary
unconsolidated sediments in the study area using shallow seismic reflection surveys, drilling, and
borehole geophysical logging. During the three year project a total of 65 shallow seismic test sites
and 10 line-km of CDP (12-fold) shallow seismic reflection profiles were acquired, and over 20 new
boreholes were drilled within the survey area. Initial seismic test results suggested that there were
areas in the Shubenacadie basin where bedrock was at depths greater than 100 m below surface.
This was subsequently confirmed by NSDNR drilling. The test sites were used to determine the
optimum locations for followup seismic profiling in the Shubenacadie valley (1994) and the
Musquodoboit valley (1995). The seismic sections and drilling results have clearly delineated
Cretaceous sediments in basins buried beneath glacial cover and have substantially increased the
known area1 extent of buried Cretaceous basins (from ~1 km2 to >57 km* in the Shubenacadie and
Musquodoboit valleys alone). Analyses of core samples have shown that these basins may harbour
economic quantities of kaolin suitable for use in the paper industry. Presentation of preliminary
results of the work in November 1995 resulted in the immediate staking of over 80,000 acres (2,000
claims) in the Shubenacadie, Musquodoboit and Antigonish valleys.
-
-
-
Borehole Vector Magnetics: The Mcconnell Deposit, Sudbury, Canada
Authors Edna L. Mueller, William A. Morris, W. Hamilton, Patrick G. Killeen and Steve BalchIn this paper we investigate the potential advantages of employing vector, or 3-component
magnetic data. Vector magnetics have been applied in previous studies in a variety of
scenarios: land-based, borehole, and marine. The present study focuses upon vector
magnetic data from a series of boreholes around the McConnell nickel deposit located
within the Sudbury Basin, Canada.
-
-
-
Borehole Correlation In Mineral Deposits Using Geophysical Parameters: Duck Pond, Newfoundland
Authors William A. Morris and Sean E. WalkerCorrelation of geophysical well logs is an exploration technique that has been employed
for many years in oil exploration. Over the past decade, a number of new slimline tools
have been introduced advancing the application of logging to the smaller diameter mineral
exploration boreholes. Interpretation of this data may follow a number of paths. Through
the collaborative use of procedures such as: a) univariate, bivariate, or multivariate
statistical methods it is often possible to characterize some lithologies that are defined by
distinctive physical property signatures; and b) the correlation of distinctive geophysical
signatures between adjacent boreholes can be used to establish structural features of the
subsurface. In this paper we show that gridding of geophysical parameters as
conventionally applied to both ground and airborne surveys can also be applied to a suite
of borehole data to produce an image of the subsurface which contains information on
both structure and lithology. In this example we present results from a multi-well and
multi-parameter survey of the volcanogenic massive sulphide deposit from Duck Pond,
Newfoundland.
-
-
-
The Application Of Borehole Geophysics To The Delineation Of Leachate Contamination At The Trail Road Landfill Site: Nepean, Ontario
Authors Daron G. Abbey, C. Jonathan Mwenifumbo and Patrick G. KilleenThe sanitary landfill site poses many monitoring problems for the environmental scientist. An understanding of
the materials and processes controlling the distribution of leachate in the groundwater at a landfill site is an
essential component of landfill management. The Trail Road landfill site in Nepean, Ontario, is perched upon a
sand and gravel ridge which is part of a lacustrine silty clay plain. The delineation and monitoring of leachate
contamination, created by the decomposing municipal solid waste mixing with groundwater, is presently carried
out through chemical sampling of monitoring wells. Such monitoring of a complex and hydraulically conductive
environment, is expensive and time consuming because water samples must be analyzed in a laboratory.
Borehole geophysical logging of eight of these monitoring wells showed that the delineation of leachate plumes
could be accomplished through a full suite of borehole geophysical logs. The logs acquired included: natural
gamma ray, density, total magnetic field, magnetic susceptibility, electrical conductivity, and temperature. The
use of a full suite of logs provided a measure of the in-situ physical properties of all the components of the
subsurface, including air, water, and sediments. Chemical sampling provided only an inventory of ions present in
the groundwater. The geophysical logs in this study were acquired, processed and interpreted, in a shorter period
than the chemical sampling, and provided information allowing for a more refined geological interpretation, than
from drilling alone. Anomalous physical properties, interpreted to be the result of the presence of leachate
contamination, correlated well with data from chemical sampling which showed elevated levels of leachate
indicator ions, such as, calcium, magnesium, chloride, sulphate, potassium, ammonia, dissolved organic carbon
(DOC), phenols and iron. It was concluded that an interpretation of borehole geophysical logs produced a more
accurate delineation of areas of leachate contamination at the Trail Road landfill site, more directly (i.e. in situ).
and with greater efficiency and simplicity than chemical sampling.
-
-
-
Geophysical Borehole Logging In Massive Carbonates Whitmoyer Laboratories Superfund Site Meyerstown, Pa
Authors Bill Bour and Craig B. ClemensCorrelation within massive carbonate sequences like those present in central Petmsylvania’s
Lebanon Valley is often difficult because the units contain few distinct marker beds and the
contacts between units are frequently gradational. This project demonstrated that correlations
among boreholes can successfully be made using a combination of geophysical logs,
particularly natural gamma, high resolution density and sonic. The technique involves
positioning logs from several of the deepest holes on cross sections at the best estimated
structural elevation (correcting for regional dip), comparing the general shape of the natural
gamma curve and adjusting the logs positions for a best fit. Once a datum has been
hypothesized, (all) the logs are examined for anomalies that might be traced through. The high
resolution density proved capable of identifying small fractures which appeared to correlate
along strata lines with the gamma. These hypothetical “marker beds” are projected onto as
many logs as possible to verify the anomaly. Once an anomaly (bed) is identitied on several
logs over a sutXciently wide area, three point strike and dip calculations are performed to verify
that the correlations fit the regional pattern.
This technique is not particularly new, it has been used in subsurface investigations for
decades. The application to massive units with only the most subtle marker beds, however, has
not been particularly successful. It proved successful at this site because of the use of sensitive
gamma and density sondes, and by a large number (62) of boreholes, a third of which penetrate
over 400 feet of section. (Although only two wells intersected the Ontelaunee-Amiville contact.)
Only very slight density (lower) and velocity (faster) differences were noted between the
dolomitic limestone (bioherm) of the Ontelaunee Formation and the limestones of the Amwille
and Epler Formations. These differences were so slight as to not be noticed until the logs were
positioned correctly on the sections by gamma and density log correlations.
-
-
-
Borehole Geophysics Used To Characterize Vertical Fractures And Their Connections To Bedding Plane Aquifers In Dolomite
More LessGeophysical logs in an array of six boreholes in argillaceous dolomite at a contamination site in northern Illinois
intersect four aquifers: a shallow bedding plane fracture, a vertical fracture, and two deeper permeable beds. The
vertical fracture aquifer appears to be representative of a set of such fractures dipping at about 85 degrees and
striking approximately northeast. Cross-borehole flow measurement techniques are used to investigate the
properties of the three horizontal aquifers, and to infer the character of the connection between the vertical fracture
and the deeper horizontal aquifers. The data indicate that the vertical fracture and the shallow bedding plane have
transmissivities nearly an order of magnitude greater than those of the two deeper horizontal aquifers in the
vicinity of the point where they intersect boreholes. The data also indicate that the deeper aquifers are
characterized by a storage coefficient of about 2x10”. The bedding plane and vertical fracture aquifers cannot be
modeled as confined aquifers, although relatively large storage coefficient values characterize models that most
closely approximate the variation of flow in the shallow bedding plane aquifer. The cross-borehole flow
experiments suggest that the vertical fracture is hydraulically connected with the deeper horizontal fractures, but
that fracture aperture decreases somewhat with depth.
-