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By Donald Brisebois

The mining of high-grade, narrow vein deposits is an important field of activity in the precious metal mining sector. The principle factor that has undermined the profitability and effectiveness of mining such ore zones is the substantial dilution that occurs when blasting with explosives during extraction. In order to minimise dilution, the Thermal Fragmentation Mining Method enables the operator to extract a narrow mineralised corridor, 50 cm to 1 metre wide (according to the width of the vein), between two sub-level drifts. By inserting a strong burner powered by diesel fuel and compressed air into a pilot hole previously drilled directly into the vein, a thermal reaction is created, spalling the rock and enlarging the hole to 80 cm in diameter. The remaining ore between the thermal holes is broken loose using low powered explosives, leaving the waste walls intact. This patented method produces highly concentrated ore, resulting in 400% - 500% less dilution when compared to conventional mining methods. The mining method reduces the environmental affects of mining operations since much smaller quantities of rock are displaced, stockpiled, and treated using chemical agents. The fully mechanised equipment operated by a 2-person team (1 thermal fragmentation operator, 1 drilling operator) maximises the effectiveness of skilled personnel, and increases productivity and safety. The Thermal Fragmentation is currently employed in 3 mining operations in North America.

May 1, 2010

By H. K. Olsen, B. Thomassen, H. K. Schønwandt, L. Grahl-Madsen, H. Stendal

The central part of the early Proterozoic Ketilidian orogen in South Greenland consists of an I-type granitoid batholith transected by four regional NE-SW-trending shear zones. Thebatholith was probably emplaced during subduction, from the south toward the Archaean craton in the north, in a sinistral transpressional system. A regional sediment sampling program covering5000km2shows a close connection between a gold-mineralized trend and one of the major shearzones within the epizonal facies of the batholith. The gold mineralization is not directly related to the major shear zones, but occurs in quartz-veined and silicified second-order structures. High-grade(up to 114 ppm Au over 6 m) low-tonnage mineralization is found within these second-order structures cutting both amphibolites and granitoids. The mineralization is characterized by negligible or small alteration halos. Gold is associated with various element combinations of enhanced As-Bi-W-Cu, which indicate that the mineralization is mesothermal in origin.

Jan 1, 1995

By Engin Burak Anil

Objective, accurate, and fast assessment of damage to buildings after an earthquake is crucial for timely remediation of material losses and safety of occupants of buildings. Laser scanners are promising sensors for collecting geometrical data regarding the damaged states of buildings, as they are able to provide high coverage and accuracy at long ranges. Yet, we have limited knowledge on the performance of laser scanners for detecting earthquake damage, and requirements of such data collection. This paper focuses on characterizing the performance of laser scanners for detecting thin cracks for damage assessment of reinforced concrete frames. We identified a series of crack parameters based on the state-of-the-art damage assessment codes and standards. Similarly, we identified parameters, which affect the performance of laser scanners for detecting cracks, based on prior research in this area. We studied the width, depth, and orientation of cracks; sampling interval of the scanner, and the range of the laser beam from the surface. Effects of these parameters on the detection of the minimum crack size were determined in an experimental setting. An automated algorithm was used to analyze the data. The results show that it is possible to detect as small as ~1mm cracks.

Aug 1, 2013

By B. J. Morash

"The six mineable coal seams at Quintette Coal Limited (QCL) vary in thickness from 0.75 m to 9.5 m and include waste partings varying from 0.2 m to 4 m thick. They are highly faulted and folded in some areas and dip angles range from horizontal to 90 degrees. Due to this variation in thickness and orientation of the seams, several different mining methods are used to economically recover the coal. The key to QCL's success depends on the timely collection of detailed geology data and on mine planning which allows selection of the best method of mining to achieve maximum coal recovery with minimum dilution and cost. This paper will describe the various methods of mining employed and the criteria used to select them. IntroductionThe unique challenge in mining at Quintette Coal Limited (QCL) is to extract large quantities of coal and waste, from a complex orebody, with constricted areas for mining and waste disposal. This challenge dictates the mining of as many as four 10 m benches per year, through complicated coal structures, from three separate open pits with a total of 19coal seams. This total is made up of 5 seams at Mesa, 8 seams at Wolverine and 6 seams at Shikano (Fig. 1).Computer-aided mine planning and scheduling is carried out on a routine basis to ensure the prudent selection of methods of mining, to produce plans which ensure delivery of appropriately blended raw coals to the plant, and to coordinate disposal of large quantities of waste.Several methods of mining are applied simultaneously, and as a result coal and waste are released at different rates from twelve to fifteen mining faces. In order to ensure uninterrupted flow of material from excavators and to utilize the truck fleet effectively, a computerized dispatch system is employed.GeologyGenerally, geological conditions can be related to structural (faults and dip angle) and/or stratigraphic (coal seam and interseam waste thickness) sources"

Jan 1, 1988

By Rick Coleman, Chelvan (Chevy) Veloo

"P.T. Freeport Indonesia's lrian Jaya Operation has been producing copper concentrate continuously since 1972. Numerous ore discoveries and five mill expansion programs have seen the initial milling rate of 7,200 MTPD escalate to the present rate of 125,000 MTPD, producing 2.5 million pounds of copper and 3,500 troy ounces of gold per day. The latest expansion, commissioned in February 1995, incorporates a 34 foot Semi- Autogenous Grinding (SAG) Mill, two 20'x30' Ball Mills, conventional roughing, cleaner column flotation, and attendant upgrades to the existing concentrate pumping and dewatering facilities. This paper will describe the SAG Plant flowsheet, and focus on the key training issues which contributed to a successful plant start-up.IntroductionP.T. Freeport Indonesia's operations in the Ertsberg mining district are located in the Jayawijaya Mountains of Irian Jaya, the easternmost province of the Republic of Indonesia. P.T. Freeport Indonesia (PTFI), the operator, is owned by Freeport MacMoRan Copper and Gold (81.3%), the Government of Indonesia (9.4%), and private Indonesian investors (9.4%). Geographical location, and sailing distances are provided on the attached location map.The operation stretches over 7 4 miles ( 114 km) from the dewatering and concentrate shipping facility at the Port of Amamapare on the Arafura Sea to the Grasberg open pit located at 3400m. The regional geology is covered in detail by Van Nort et al (1991 ), with current proven and probable reserves estimated at 1.13 billion metric tonnes grading 1.30% Copper, 1.42 ppm Gold, and 4.06 ppm Silver. The Grasberg open pit mining operation provides 92% of the mill feed, and is described in detail by Hickson (1991). The remainder of the mill feed is derived from several underground block caving operations. Current production rates provide a mine life in excess of 25 years. However, very favorable geology in the area leads to expectations that additional reserves will extend the life of the operation considerably."

Jan 1, 1996

By Don Ritz

Smart leaders focus on safety even in tough times. Businesses that retreat into survival mode and ignore safety do so at their peril, risking loss of employee and stakeholder confidence and exposing themselves to financial and reputational loss they can ill afford. It?s a moment of truth when employees and stakeholders learn whether safety is truly your priority or just a convenient cliché for good times. Visionary leaders who build safety culture even in a downturn maintain people?s trust, prevent loss, and position the organization for enhanced success as times improve. Safety is the right business focus in good times and bad.

May 1, 2009

By E. C. Grunsky, B. W. Smee

"The development of low-cost, rapid multielement analytical techniques has generated large geochemical databases in many exploration programs. When a sampling program consists of several thousand samples, the resulting data matrix is enormous and effective interpretation using all of the elements individually becomes burdensome. However, the application of multivariate statistical techniques can extract geochemical patterns related to the underlying geology, weathering, alteration and mineralization. Imaging the results over topography enhances the interpretation of these patterns. Examples of this approach are shown from mineral exploration programs in Canada and Mexico. IntroductionThere has been a dramatic change in the effectiveness of using geochemical survey data in the past ten years. This is mostly due to:• lower cost of geochemical analysis;• lower detection limits;• new methods of multi-element analysis;• a marked decrease in the turnaround time;and• the intelligent use of computers in presenting geochemical data.Geochemical surveys commonly have two objectives: locating abnormal concentrations of ore-forming or pathfinder elements and characterizing the underlying host lithologies. Geochemical surveys often employ a wide range of sample media that may typically include whole rock lithogeochemistry, various soil horizons, till and basal till sampling, stream sediments, lake sediments, and various forms of weathered regolith. Each of these sample media will exhibit a unique element distribution that must be factored in the interpretation phase of a geochemical survey study. This can become a cumbersome process if univariate data handling methods are employed."

Jan 1, 2003

By Bahaa Hussein

Considerable number of methods and procedures has been introduced for trending and progress reporting of engineering, procurement and construction projects. This paper introduces a novel method, designed to augment the set of indices for measuring schedule performance. The concept behind the developed method is to provide early warning by dynamically evaluating the schedule cumulative impact of construction projects. The proposed method is designed to highlight the gradual deterioration in schedule status resulting in a cumulative impact due to the aggregation of small delays encountered during the execution of non-critical activities, and can be used as an add-on utility to existing software systems that perform CPM scheduling. The proposed method is based on a developed formulation for quantification of the Schedule Compression Index, which takes into consideration the remaining project activities durations. The index is developed based on periodic comparisons of ?Current Schedules? and the project ?Baseline Schedule? using the summation of the remaining activities durations. A numerical example is presented to demonstrate the application and capabilities of the developed method. It is expected that the developed index together with other schedule performance indices would be of value to decision makers and members of project teams.

Aug 1, 2013

By Shintaro Takamiya, Kazunari Yoshida

"Recently, small sized micro-needles for medical are required more frequently by patients. The biggest reason is that it presents great burden on the patients, due to the size of the needle injection. People need to use a very small needle to lower the pain, but the downfall is that it makes them more expensive due to their complicated manufacturing method. Therefore, we need to fabricate a needle by wire-drawing to decrease its price. Tube-drawing is beneficial for its production value; however, in conventional tube-drawing it is difficult of control the wall thickness of the tube and makes it 1mmor lower in diameter. That is why, we propose fluid-mandrel drawing for new tube drawing. This method allows fabrication of a fine tube by using the pressure of the fluid in the tube. In this research, the goal is the fabrication of a fine tube by fluid-mandrel drawing and its evaluation. Finally, the fabrication of a fine tube by fluid-mandrel drawing was conducted and in result a tube with a diameter of 0.2mm, high strength and thin wall and fine inner surface was drawn, which can be used as a lesser pain micro-needle.INTRODUCTIONThe main manufacturing method of the current medical needles is roll forming. With this method, it is difficult to make a tube with a diameter lower than 1mm. Deep drawing has been proposed and used as method to further reduce the diameter, but this method is costly and the injection needle obtained by this method is several times more expensive.Therefore, we need to obtain a fine medical needle by drawing process that can be mass-produced and inexpensively manufactured. However, with the conventional drawing process, it is not possible to obtain a syringe needle with a reduced diameter easily, that is why, a fluid-mandrel drawing has been proposed which can reduce the diameter without damaging the inner surface. The methodology of the method is, a fluid is filled in the sealed tube and the pressure inside the tube during drawing is responsible for the good inner surface and wall thickness. It is also expected that the fluid can be easily discarded and that the tube can be manufactured on a long scale."

Jan 1, 2017

By M. Souley, G. Armand, M. Ghoreychi, D. Seyedi, J. -B. Kazmierczak

"An anisotropic constitutive model is proposed in this paper accounting for both structural anisotropy and induced anisotropic plasticity. It is assumed that the rock is composed of a matrix and of potential planes of weakness. The matrix is assumed to be linear, transversely isotropic and the plasticity is described by a non linear yield function where the parameters are deduced from the nonlinear Hoek-Brown envelopes in pre- and post-peak, and derived from the laboratory characterization. A non-associated flow rule is used with a distinction between compression and extensional stress paths, as well as the absence of volumetric strain beyond large plastic distortion.The planes of weakness are considered as known a priori or assumed to be oriented perpendicular to the direction of the current minor principal stress. An elastic-perfectly plastic behavior according to the Mohr-Coulomb criterion is assumed in the planes of weakness; while the elastic part is considered as linear and transversely isotropic.Finally, the proposed model was implemented in FLAC3D and used to simulate triaxial compressions to provide a verification of the implementation. The applicability of the implemented model to reproduce damage (pre-peak) and/or failure developments around a circular opening is checked. The GCS drift, one of the mine-by experiments set up at the main level of the Meuse/Haute-Marne Underground Research Laboratory, is selected for this first application."

Jan 1, 2015

By R. Bonnar, R. J. McH. Clark

"The Cheminis gold mineralization zone is approximately 6.5 km west of the Kerr Addison Mine along the Larder Lake Shear Zone, in the southern part of the Abitibi Greenstone Belt. The zone is very similar in appearance to the flow ore at the Kerr Addison Mine and occurs at the same stratigraphic position. Drilling has demonstrated that the gold mineralization at Cheminis persists to a depth of over 3000 ft .The mineralization is hosted by a pyritic, tuffaceous sediment which occurs within a sequence of volcanics and sediments which have been pervasively carbonatized. The gold is largely enclosed within pyrite grains and the amount of gold in the layers of pyrite increases in the layers closest to a graphitic f ault zone.It is suggested that the gold mineralization may be primarily related to the syngenetic sulphide concentrations formed during fumarolic activity on the seafloor along the Larder Lake Shear Zone. At a later stage a hydrothermal event associated with alkalic volcanism may have resulted in regional carbonatization and further concentration of the gold in the vicinity of fault zones."

Jan 1, 1987

By James F. Archibald

Research has been conducted for the Workplace Safety and Insurance Board of Ontario (WSIB) to characterize thin, spray-on lining materials (TSLs), as well as combinations of TSLs and conventional spray supports, and to assess their capacity for inhibiting damage created by mining-induced rockbursts. This study has been performed to assess the capabilities of such support systems for preventing rock and support material damage that often results due to rockbursting. A variety of TSLs and other spray support media were subjected to the effects of simulated rockbursting, through use of explosive detonation trials, to evaluate their damage mitigation capacity. Results have validated that TSLs and variant layer combinations may be as effective as or better than conventional support materials for mitigating rockburst or like damage in highly stressed mine environments. In civil engineering construction, and typically in underground tunneling operations where concrete linings are applied, liner deterioration is a continuing and pervasive problem that often requires expensive and time-consuming rehabilitation effort. The ability of TSLs to provide effective concrete structural reinforcement while providing sustainable resistance against underground or restricted environmental hazards, as with fires or dynamic failure events, may permit wider use of TSLs than is currently foreseen by the mining industry. Significant benefits for use of TSL materials in concrete liner rehabilitation and for concrete material protection have been assessed.

May 1, 2006

1. Scope of project In South Australia, the Western Mining Corporation operates the underground copper and uranium mine Olympic Dam. The deposits concerned are enormous (approx. 570 million tons) and have been mined since 1988. At the end of 1996, Western Mining decided to increase the capacity of Olympic Dam from 85,000 t.p.a. to 200,000 t.p.a. Planning At this point, SIEMAG-GHH Mining Division was asked to carry out a study including the planning of the entire shaft hoisting operations and calculation of the investment and operating costs involved. With the assistance of Australian partners, the study was completed within a single month. The principal points of the study were as follows: ? Planning of the hoisting machinery for 1,375 tons per hour from the surge bin below ground to the discharge bunker above ground. ? Optimisation of the hoisting operation with regard to maximum availability and safety. ? Optimisation of the time schedule to minimise the financing costs of the investment. ? Statement of the investment and operating costs. ? Comparison of the technical data, design and availability of the planned machinery with reference plants. Construction of the plant Following acceptance of the study, the decision was taken within a few weeks to implement it. SIEMAG Transplan GmbH received the order to execute the entire shaft hoisting machinery on the basis of the study submitted. The decisive factors in placing the order were: ? Convincing study, adherence to schedule ? Reference to comparable plants elsewhere ? Reference with regard to availability.

May 1, 2003

By M. F. Goudge

THE present century has witnessed an amazing transformation in the uses of limestone. From being mainly a structural material, a role it has played since the beginning of civilization, it has become one of the in-dispensable raw materials for use in the great chemical and metallurgical industries that play such a vital part in the economic life of the nations today. Its uses have become so diversified and numerous that it enters, directly or indirectly, into nearly every phase of modern life. In this introductory paper it is proposed merely to outline the general usefulness of limestone and to point out some of its salient features, and to leave any detailed discussion of uses to the papers that follow. The term limestone as herein used embraces all kinds from the variety known as high-calcium limestone, which is composed almost entirely of calcite, to the dolomitic variety, composed largely or entirely of the mineral dolomite. Lime is simply calcined limestone and, in considering the uses of limestone, the uses of lime should also be included, particularly in view of the fact that, in many processes, it is possible to use limestone in either the raw or the calcined state.

Jan 1, 1939

By M. A. Rabah

This study aims to recover europium, yttrium metals, some valuable salts or oxides from the white powder (apatite) coating the inner surface of spent florescent lamps (SFLs). Pressure leaching using sulphuric/nitric acid successfully dissolved the metals of interest. Europium or yttrium metals were obtained by hydrogen reduction of their oxides. Addition of potassium thiocyanate converted the dissolved sulphates to thiocyanates. Selective separation of Eu and Y was then carried out by solvent extraction from the thiocyanate solution. The used solvent was trimethyl-benzylammonium chloride. N-trihutylphosphate in 1 M nitric acid was used to strip the metal loaded in the organic phase. Results showed that the quality of the cleaned glass tubes of the SFL met the standard requirement for the lamp manufacture. The white powder (WP) is composed of calcium sulphate 35.2%, phosphate 61.5% and oxides of europium and yttrium 1.65%wt. respectively. Autoclave digestion of the WP for 4 h at 120°C and 500 kPa in sulphuric acid/nitric acid mixture dissolved 96.4% of yttrium and 92.8% of europium. The conversion rate of sulphate to thiocyanate was favoured at low temperature. Stripping of Eu and Y from the loaded organic phase behaved in an opposite way. A metal separation factor of 9.4 was obtained. ate recovered europium and yttrium salts were selectively separated using ethyl alcohol or dilute nitric acid. Yttrium was very soluble while europium was not. Europium and yttrium metals were obtained by hydrogen gas reduction at 850°C and 1575°C respectively.

Jan 1, 2004

By C J. Coveney

This paper, after a brief introduction to the mineralization and structure in the mine area, outlines the methods now being employed for grade control at Bethlehem Copper Corporation. Sampling, subgrade drilling, blasting and the actual outlining of the ore are among the topics covered. The paper concludes with a summary of the results obtained, showing a reduction in dilution and an improvement in the grade of the copper ore going to the mill. Introduction T HE Bethlehem property is located in southern British Columbia in the Highland Valley about 30 miles southeast of the town of Ashcroft. The property is located within the Guichon batholith. The rock comprising the batholith is a massive, coarse-textured diorite, which, at Bethlehem, has been intruded by a younger quartz diorite, porphyries and breccia, referred to as the "Younger Complex." Mineralization, consisting of chalcopyrite and bornite with minor pyrite and molybdenite, occurs as disseminations, fracture fillings and coarse blebs. The ore zone lies close to the Guichon -Younger Complex contact where, prior to the development of the breccia, the rocks were shattered and jointed. Subsequent mineral

Jan 1, 1965

By G. Lucas

"Material substitution occurs continuously in response to competitive and economic pressures. Technical development can accelerate or slow substitution by improving the performance of the invading or defending material. The choices are seldom simple and have to be made in the context of continuous commercial change.The development and commercialization of a new aluminum material is examined. The material has been introduced into· several different markets, so it is possible to compare and contrast the degree of success obtained in each.IntroductionAluminum-based materials have been in use for over one hundred years and , therefore, the development of a new family of alloys is rare. In the early 1970s, Dr. L.R. Morris and his coworkers at Alcan' s Kingston Research Centre started work on what was, at the time, something of a scientific curiosity-a family of alloys strengthened by an unusual mechanism.This paper deals with the development and commercialization of what became known as the Alcan 255 alloys"". These alloys have found uses in several markets, usually as improved substitutes for existing materials. Forecasting the usefulness of a substitute material in an existing marketplace is difficult, in part, because even material users are seldom able to specify precisely their requirements. This uncertainty can cause the failure of some substitutions but can also lead to opportunities which were not initially obvious.Technical BackgroundPure aluminum is a soft, weak material. It can be strengthened by the addition of various alloying elements and by work hardening. Alloying elements usually act by forming solid solutions which are stronger than the pure metal or by precipitating during heat treating or aging and so preventing the easy movement of dislocations during deformation. Elements which can perform either role had been investigated for decades and were thought to offer little chance of technical breakthrough in 1970. An outgrowth of the then new and exciting research on directional solidification seemed, however, to offer such promise.Some aluminum-iran-manganese alloys will solidify under certain conditions as 'coupled growth' eutectics (Figs. I and 2). The microstructure shows one phase growing as long rods through the other. This is an uncommon structure and it was investigated to see if it had equally unusual properties. On deformation by rolling the rods were broken up into small equiaxed , evenly-spaced particles (Fig. 3). Materials with this structure were found to be stronger than other alloys with similar amounts of alloying addition, and to resist thermal softening remarkably well. This combination of properties was thought initially to be due directly to the particles by a dispersion strengthening mechanism, but later this was found not to be strictly true."

Jan 1, 1987

By Yve Potvin, Fabien Miller, Deni Jacob

"The potential benefits of measuring the volume of excavated open stope are enormous. By comparing the actual excavation of the orebody contour, it is possible to determine the “real"" amount of mining dilution, as well as the ore left in place. Noranda Technology Centre (NTC) has developed a stope survey system that allows for rapid and efficency measurement of underground excavation volumes. The system comprises a commercial laser (EDM), a set of lightweight rigid rods, an automated scanning device, a hand-held data logger and Autocad-based software for volume calculation and drawing manipulations. This system is an invaluable tool for the optimization of mining practices and could also be used for the delineation of caving areas. IntroductionDilution is the most common and devastating mine disease. In some instance s it could systematically cripple the profitability of an operation, and in more extreme cases, it could become a terminal disease. The Northern Miner Journal (1988) reported that many operations have closed because of uncontrolled dilution, before they even completed their first year of production. Other studies (Pakalnis, 1986) have shown that approximately 40% of all underground operations have more than 20% dilution. Considering that every ton of dilution costs in the neighbourhood of $25, the total direct cost of dilution to the Canadian mining industry may easily exceed one hundred million dollars per year.The dilution problem has been a major concern to Noranda Minerals for some time and in 1984 a comprehensive geomechanics research program was created at the Noranda Technology Centre (NTC) in Pointe-Claire, Quebec. New empirical stope dimensioning techniques, improved cable bolting techniques and sophisticated ground control instrumentation projects (among others) contributed to improve the situation at Noranda.A new tool which can have a very significant impact on the ""war"" against dilution is being developed by the Noranda Technology Centre. The laser stope survey system allows for a rapid, precise and efficient measurement of underground excavation volumes. By comparing the excavation planned with the volume excavated, it becomes possible to determine the ""real"" amount of mining dilution as well as the amount of ore left in place. This system may also allow for early detection of a dilution problem. As with other diseases, early detection provides the best chance for a fast and total recovery."

Jan 1, 1992

By H. Utsunomiya

Most magnesium alloy sheets show low deformability in rolling. Edge cracks and transverse fractures are common difficulties. In addition, rolled sheets show well-developed basal texture <0001>//ND. The texture causes high anisotropy in mechanical properties and low formability in subsequent metal forming. Differential-speed rolling, where the upper and the lower rolls rotate at different speeds, introduces shear deformation through the thickness. Not rolling texture but shear texture evolves in the sheet so that the asymmetric rolling can be a method of texture control. However the primary slip system of the hcp alloy, is basal, the shear texture should be also basal. Differences between the two basal textures, i.e., the rolling texture and the shear texture, have not been understood completely. In this study, conventional (same-speed) rolling and differential-speed rolling have been applied to commercial AZ31B sheets at 623K. Microstructures, textures and mechanical properties of the rolled sheets before/after annealing are compared. It is found that the basal texture is more pronounced by the asymmetric rolling. On the other hand, the asymmetric rolling is effective to decrease the grain size and the planar anisotropy.

Jan 1, 2006

By A. P. Annan, C. Vaughan, J. L. Davis

"The increase in the price of gold in the last decade has led to a significant increase in placer gold exploration around the world. Placer deposits occur in depressions along ancient river and stream channels. In many instances these channels have been covered with materials from subsequent erosion or glacial activity. Use of high resolution geophysical techniques to map the bedrock and soil strata can improve the probability of finding the placer deposits. The buried bedrock surface is often the factor controlling deposition. Ground probing radar (GPR) and seismic sounding are complementary high resolution techniques which can be used to map bedrock topography and soil stratigraphy. Current radar instrumentation operates best in coarse grained soils. Penetration depths of up to 30 m have been attained, and stratigraphic horizons have been mapped with spatial resolutions of better than 0.5 m. Although its spatial resolution is considerably lower than radar, seismic refraction achieves superior penetration in electrically conductive environments such as clay and silt soils. The seismic refraction method thus proves to be complementary to the radar method. The seismic reflection technique is analogous to the radar method. Current seismic instrumentation and energy sources however, provide limited spatial resolution and do not permit the use of seismic reflection for reflecting horizons lying at depths of less than 20 m to 30 m.This paper discusses the use of both radar and seismic methods for placer exploration. The radar and seismic techniques, the field methods, equipment, and data displays are presented. Field examples illustrate the high resolution mapping capabilities of the techniques. The radar data agree very well with the borehole data, and in fact they sometimes detect subtle soil strata variations associated with changes of permeability that were not initially observed in the borehole logging. The radar method can give a continuous profile of water table and bedrock in sandy soils. Seismic soundings are necessary to differentiate between the bedrock and water table reflections observed by the radar."

Jan 1, 1987