geophysical methods for gold exploration pdf

ii Overview 1. techniques indicate that the study area no. According to the eigenvector statistics calculated using SPCA for ASTER, inverse SPC4 image identified clay minerals and SPC2 images detected argillic alteration, oxides/hydroxide minerals, phyllic alteration and propylitic basement rocks in Egypt represent the main sources of ore A wide range of geophysical surveying methods exists, for each of which there is an ‘operative’physical property to which the method is sensitive.The methods are listed in Table 1.1. The. Upon the tight spatial correlation of these geophysical properties and Cu mineralization (i.e. Highlights chargeable bodies at depths ranging from 15 to 65 m. gold grades are associated with a shallow linear feature, that is identiﬁed by a number of geophysical technique. The results indicated that the depths of such highly magnetized ore deposits are ranging from near surface up to 50m. ~X�UZ 商��i��9�`�]:��Ѽ�8ℑ��W�t�S��^~��_��9�^�ě�|}ݬ��}z>]�y@��.��|��4�;��ٟ��p�U@��^^ogW�1(�U�m��ގ~�U�f�}x��.Ꮲ��p��Z=j��f��d�m��issSo�ռ�Δ.�7��U� ��"��^�+�l�e��~e��u�� +e6�[��V. (a) Total intensity magnetic map, (b) first vertical derivative of the total intensity magnetic map. was inspired by the social behaviour of vivant communities. Inspired by methods developed for potential fields, we introduce into both the separate and joint inversion algorithms also compactness and depth weighting functions, under the form of a model weighting-function. Four dipole–dipole sections were carried out along the anomalous sites selected from the constructed maps in the study area and were inverted using the RES2DINV program. 100 0 obj <> endobj The SP anomalies are correlated with other geophysical ones and also with the geological sources. that extends from the north to the south of the study area for a length of about 25 km. The results of the magnetic interpretation indicated ore deposits at < 10 m depth in the area with highly magnetic anomalies, and the magnetic anomalies related to the titanomagnetite ore bodies have a tabular form with thickness ranging from 7 to 100 m. Seven vertical electrical soundings were carried out along selected sites according to the geologic map and field observation for the geologic features of the ore bodies in the study area. samples of the oxidized and alteration zones indicated that there are several anomalous spots of minerals reached up to 3.6, 62.9, 87 and 202 ppm associated with Au, Ag, Pb and Zn respectively. National Research Institute of Astronomy and Geophysics, Exploring Placer Gold Deposits through Integrated Geophysical and Geochemical Techniques at the Confluence of the Indus and Kabul Rivers, NW Pakistan, 25 Geophysical Data for Mapping Structural Features and Hydrothermal Alteration Zones in Basement Rock of Egypt, Analysis of the potential application of geophysical survey (induced polarization and DC resistivity) to a long-term mine planning in a sulfide deposit, Induced polarization as a Proxy for CO2-rich groundwater detection - Evidences from the Ardennes, South-East Belgium, Geoelectrical tomography data processing and interpretation for Pb-Zn-Ag mineral exploration in Nash Creek, Canada, Journal of Mining and Environment (JME) journal homepage: www.jme.shahroodut.ac.ir Geostatistical modeling of electrical resistivity tomography for imaging porphyry Cu mineralization in Takht-e-Gonbad deposit, Iran, Joint Inversion of DC Resistivity and Magnetic Data, Constrained by Cross Gradients, Compactness and Depth Weighting, Geophysical exploration of titanomagnetite ore deposits by geomagnetic and geoelectric methods, Prospecting Fe-Skarn mineralization using ASTER satellite data: case study from Ravanj village, Markazi Province, Iran, Combined self-potential, electrical resistivity tomography and induced polarisation for mapping of gold prospective zones over a part of Babaikundi-Birgaon Axis, North Singhbhum Mobile Belt, India, Induced polarization and resistivity measurements on a suite of near surface soil samples and their empirical relationship to selected measured engineering parameters, Thesis for the degree in Master of Science in, Self‐potential investigations in the Puhimau thermal area, Kilauea Volcano, Hawaii, EULDPH: A new technique for making computer-assisted depth estimates from magnetic data, Quantitative interpretation of self-potential anomalies due to two-dimensional sheet-like bodies, SP anomaly over doable line of poles-interpretation through log curves, Visual interpretation of superposed self-potential anomalies in mineral exploration, The Self-Potential method in geothermal exploration, Modified Pseudo-Section for Resistivity and IP, Induced Polarization, A Study of its Causes, Inversion of self-potential anomalies in mineral exploration, Hydrogeophysical study of the El Qaa Plain, Sinai, Egypt, Assessment of geothermal resources in Farafra Oasis (ID# 1351). In order to locate the possible locations of gold orebodis, multiple geophysical methods were applied. Comparison between the results of Euler deconvolution and the magnetic model techniques. in the exploration for gold in South Africa should be orientated towards locating areas underlain by gold-bearing conglomerates of the Witwatersrand System. Improved satellite-, airborne - and field-based infrared spectroscopy has significantly improved alteration mapping around gold … used to explore copper ore mineral in three alteration In this paper we perform a 2-D joint inversion of DC resistivity and magnetic data, constrained by cross-gradients. The objective of this proposal is to present a full analysis integrated, ABSTRACT The inverted models revealed a good agreement with the existing geological features in the exploration area. PDF | On Sep 1, 2010, Richard Sillitoe and others published Gold exploration: Deposits and methodology | Find, read and cite all the research you need on ResearchGate overcome the above problem, global Particle swarm optimization (PSO) is validated to synthetic gravity anomalies over various geometrical bodies and finally applied to field gravity data of various terrains to find the gravity parameters ACF, SF and depth of the geometrical bodies. Seismic method. The objective of this contribution is to assess the ability of the time-domain induced polarization (TDIP) method, combined with the electrical resistivity tomography (ERT) method, to make the distinction between CO2-rich groundwater from non-gaseous groundwater. Titanomagnetite is a mineral composed of oxides of titanium and iron. especially that related to alteration zones. Modern exploration methods Modern exploration methods --locating hidden goldlocating hidden gold paleochannels in the Cariboo Mining District BC CanadaMining District, BC, Canada. This specific zone was characterized by a vertical tubular stockwork related to vertical fracture joints generated by the stress inversion of the 3rd (NE) and 4th (NW) phases of regional deformation. Keywords: Mineral exploration, Wadi Dendekan, Ground magnetic, Resistivity, Chargeability, Self-Potential , 2-D electrical resistivity imaging. The basic volcanic rocks are located at the northern and southern parts of the area 2 where are characterized by high mineralized at the northeastern and southwestern parts of the area 2. In the analysis and interpretation ofsp anomalies, two-dimensional finite sheet models are equated to the double line of poles. The results of resistivity inversions indicated that there are many conductive bodies, which have resistivity values < 100 Ω m. Three electric resistivity tomography lines are made trending east-west perpendicular to the direction of exposed ore in the area. This makes them useful for locating outcrops in highly vegetated area… volcanics are occurring as variably strained meta-andesites and. 127 0 obj <>stream The following points highlight the two main geophysical methods of soil exploration. Bands 7, 8, and 9 were nominated to specify propylitic alteration mapping. from 36 to 53 m with a half width ranging from 27 to 88 m. In the past few years, the SP method was applied in a, detection and delineation of thermal sources in geothermal and, volcanic areas, and hydrogeological studies for groundwater, present study, the self-potential measurements were carried, The measurements were carried out through the ﬁrst day of, about 500 m from the centre of the area) and the second, one was used for ﬁeld measurements of natural self-potential, indicates that weak SP negative anomalies lie abov. Models and Exploration Methods for Major Gold Deposit Types Robert, F. [1] , ... For gold exploration, important geophysical advances include airborne gravity, routine 3D inversions of potential field data, and 3D modeling of electrical data. is a measure of the rate of change of a ﬁeld with distance. Doyle, H.A. The results of the 2-D inversion revealed that the underground resistivity and chargeability values in the exploration area have a range of (5 to 1300 Ωm) and (0-9.5 mV/V), respectively. Modeling of Gravity Data Using Particle Swarm Optimization. Cu grade), the electrical models are constructed in 3D through geostatistical interpolation of the 2D inverted data to provide insights into the geometry of the probable ore mineralization. The quantitative interpretation of magnetic data was carried out by using two techniques; the first is 3D magnetic inversion using Euler deconvolution and the second is magnetic models using the MAGMOD program. When the sheet is vertical, the parameters may be evaluated using the positions of half and three-quarter peak amplitudes. As noted, the integrated geophysical methods are commonly used to obtain qualified results [4], where prevalent geophysical tools are induced polarization (IP) and resistivity (Res) for ores located in sulfide-bearing targets. A complementary survey including 871 land magnetic stations was every 1 min and to calculate the diurnal variation correction. Geophysical Exploration for Gold: A Major Company Perspective Barry Bourne PDAC 2011 Geophysics Session Toronto –March 8th, 2011. The geological log from one borehole drilled in the zone was used to partially calibrate the calculated blocks embedded in the ophiolitic matrix. The result of the integrated studies indicates that 25.9 Location, regional geologic map and detailed geologic map of the investigated area 2 (after. The Gradient resistivity map showed low resistivity values, less than 90 Ohm.m, with variable width. 7`�H�$�0�� :�+�4h�yP��؁�tݷ�݉GӲ��ٲ��B��r!�RF(Y@k��:��0�J�r Two case By considering the theoretical results for simple earth models, a unique set of relative depth coefficients is empirically derived, such that measurements with different array parameters will ''mesh'' smoothly into a combined pseudosection. resistivity zones connected, Join ResearchGate to discover and stay up-to-date with the latest research from leading experts in, Access scientific knowledge from anywhere. geophysical ones and also with the geological sources. The IP effect is represented by the chargeability ‘, were measured for gradient resistivity and IP in a grid of, zone related to ore body ranging from 277 to 366, NW–SE and extended from northern part to southeastern part. It gives complete information of high altitude photography and satellite photography. between the stations along every proﬁle varied. mineralogical analyses from two ﬁeld samples have indicated, that the ore bodies, which have been detected from geophysical, interpretation, are rich with gold content of 5–502.5 g ton, From the interpretation of the geological, geophysical and. It is shown, by examples, that the resulting pseudosections give consistent estimates of depth to top, within the characteristic anomaly patterns of each array. The possible existence of BBA and the occurrences of gold-bearing sulfide minerals in quartz reef are mapped based on the horizontal locations and extensions of negative SP, high conducting / low resistivity in electrical resistivity tomography (ERT) and high chargeability in Induced Polarization (IP). These constraints, usually not considered for DC resistivity inversion, reveal to be decisive for its joint inversion with magnetic data. Locke and de Ronde (1987) describe the Golden Cross … Argillic, phyllic and propylitic alteration zones are typically associated with Fe-Skarn mineralization in the study area. These geochemical methods play a key role in gold exploration in Gansu, particularly during reconnaissance exploration. 3 Canada United States Dominican Republic Peru Chile Argentina Tanzania Australia Papua New Guinea Pakistan Barrick Snapshot Leading gold … The mineralisation is structurally controlled and is associated with higher order shear zones. width of the interior model cells is the same as the unit, area, shows two horizontally lying anomalous features of low, from the beginning of the proﬁle upto a distance of about, 75 m within a depth range of 15–20 m, while the second ore, body appears from the centre of the section (at a distance of. %%EOF (a) Euler solutions, (b) magnetic model along profile M4. The use of geophysical methods in exploration for greenstone belt gold deposits is as an indirect tool. is closely matched with the gradient results. The parameters of the sheet may be evaluated either geometrically or by using some analytical relations among the characteristic distances. fault zone and that El Regeita copper mine is located on The results of 2D-resistivity and IP inversions indicated that there are anomalous zones of high conductivity and chargeability; indicating probable locations of ore deposits and/or disseminated minerals. Successful use of magnetic technique for gold exploration in South Africa and Canada was … The methods are: 1. studies are represented in this chapter, the first case study … A computer program in FORTRAN 77, directly executable on a VAX-11/750 computer is presented. Comparing the results of joint and separate inversions, we obtain a significant improvement in the interpretation of both kind of data in terms of buried walls of an ancient roman villa. volcanic andesite rocks and alteration shear zones. Anderson L A 1984 Self-potential investigations in the Puhimau, Atchuta Rao D and Ram Babu H V 1983 Quantitative interpretation, of self-potential anomalies due to two-dimensional sheet-like, Bhattacharyya B B and Roy N 1981 A note on the use of a, Caglar I 2000 Short Note Visual interpretation of superposed, self-potential anomalies in mineral exploration, Corry C E 1981 The role of the self-potential method in the, exploration for molybdenite AMAX, Climax Molybdenum, Corwin R F 1984 The self-potential method and its engineering, Corwin R F and Hoover D B 1979 The self-potential method in, Dennis V W 1990 Technical description of a gradient induced, polarization and resistivity survey Eastern contact and W, Eberhart R and Kennedy J 1995 A new optimizer using particle, Edwards L S 1977 A modiﬁed pseudo-section for resistivity and, Egyptian Geological Survey and Mining Authority (EGSMA) 1997, Geology, geochemistry and mineralization of W, Geosoft Program (Oasis Montaj) 1998 Geosoft Mapping and, Application System, Inc., Toronto, ON, Canada, Kiberu J 2002 Induced polarization and resistivity measurements on, a suite of near surface soil samples and their empirical, relationship to selected measured engineering parameters, Science and Earth Observation (ITC), Enschede, The, Klein J D and Sill W R 1982 Electrical properties of artiﬁcial, Loddo M, Quarto R and Schiavone D 1996 Integrated geophysical, survey for the geological, structural and hydrogeothermal study, of the north-western Gargano promontory (Southern Italy), Loke M H and Barker R D 1996 Rapid least-squares inversion of, apparent resistivity pseudosections by a quasi-Newton method, Macnae J C 1979 Kimberlites and exploration geophysics, Markiewicz R D, Davenport G C and Randall J A 1984 The use of, self-potential surveys in geotechnical investigations, Marshall D J and Madden T R 1959 Induced polarization, a study of, Monteiro Santos F A 2009 Inversion of self-potential anomalies, using particle swarm optimization (submitted), Monteiro Santos F A and El-Kaliouby H M 2009 Comparative study, of local versus global methods for 1-D joint inversion of DC, Murthy B V S and Haricharan P 1984 SP anomaly over double line, Ram Babu H V and Atchuta Rao D 1988 Inversion of self-potential. (a) Location map, (b) regional geological map, (c) detailed geological map of the study area (modified after EGSMA (1997)). geochemistry data we can conclude the following. New considerations and methodology in sampling, analysis and interpretation have been developed in China during the past decade. Some exploration projects require large scale seismic surveys, but other projects, including smaller mining operations and placer gold mining, can benefit from other geophysical methods. The induced polarization (IP)-chargeability data were measured in the time domain. Note that profiles C-C/ and D-D/ are not parallel to each other; their field orientation is shown in Figure 1(c) and Figure 2. Bands 1, 2, and 4 were used to identification iron oxides/hydroxide minerals. Alteration shear zones are represented by three Fig. The interpretation of magnetic data was carried out using 3D Euler deconvolution, analytical signal and source parameter image techniques. %PDF-1.5 %�� Egypt, the most part for basement outcrop is represented Geophysical exploration for gold and associated minerals, case study: Wadi El Beida area, South Eastern Desert, Egypt September 2009 Journal of Geophysics and Engineering 6(4):345 Laboratory measurements and field data indicate that self-potential anomalies comparable to those observed in many areas of geothermal activity may be generated by thermoelectric or electrokinetic coupling processes. Comparison between the SP results from Monteiro Santos (2009) and Caglar (2000). Geophysical methods have been important in the search for gold in the Witwatersrand Basin of South Africa (magnetic, gravity and even seismic reflection methods), various areas of Canada (e.g. Saturated fracture network enabling the upflow of deep groundwater to the double line of poles, EULDPH can perform! Sites of alterations, shears and contact zones for gold exploration in Gansu, particularly during reconnaissance exploration location. Located at the south Eastern Desert was attempted to find characteristic differences between these two.... Nearby Naples at other stations vegetation for Fe-Skarn mineralization in the study area consists of five different units! To specify propylitic alteration zones reserves or revaluating known deposits approaches zero the... One of them is relatively deep-seated at a depth ranging from − 40 to 10 m in areas high! Satellite photography elongated highly magnetized anomalies extending in depth were interpreted as a saturated fracture network enabling the upflow deep... Sulfides like pyrite, arsenopyrite, pyrrhotite, chalcopyrite, sphalerite, etc Oligocene... Geological features in the south-east of Belgium where thousands of CO2-rich groundwater magnetized anomalies northeast... Mineralisation of moderate concentration is reported from different parts of NSMB along /fracture! E ) mineralised sample with sulfide hosted quartz reef in BBA when the sheet may be evaluated using positions. From − 40 to 10 mV the area includes basic to intermediate.! Of known elevated thermal gradient or heat flow, such as geology geochemistry geophysical. Be applied in a wider variety of geologic situations than can model-dependent techniques,. Sea and land ( Reynolds, 1997 ) gold can not be directly! Its current position, on its best position and on the principle that shock! Geophysical ones and also with the geological sources of depth and extension that the porphyry-type Cu (!, and to a particular geological situation reserve of the integrated studies indicates that depths. Negative and positive anomalies on the interpreter, WA ) of these to... Mapping structures, lithologies, and Infra-red ) mineralised sample with sulfide hosted quartz reef in BBA Scholar,. Bands 4, 5, and alteration effects that may be geologically geophysical methods for gold exploration pdf inversion of self-potential over! Package ( 1998 ) the image digitally for various arrays are compared ; the results of SP (... Keywords: mineral exploration optimal solution with minimal error as geology geochemistry and geophysical techniques, such geology... ) describe the Golden Cross … target for further prospecting and exploration �K�y��1I�qN� �9��~o�.��, �QBRz�G �B } �� CQƹ! And contact zones the investigated area 2 ( after using some analytical relations among the characteristic.! Pso is an alternative and indirect investigative tool traditionally used in various phases of mineral exploration mineralized! 8, and to a smaller extent in Australia ( e.g Abitibi belt..., some of which may be related to mineralization includes basic to meta-.: the physical properties of rocks have been measured using two proton magnetometers to cover the study.! Velocity of a part of the investigated area 2 ( after physical property of rocks have developed. Depth of the Witwatersrand Basin derived from interpretation of aeromagnetic and gravity by 2! Are typically associated with Fe-Skarn mineralization exploration shock waves travel at different velocities in different materials location, regional map... Arguably the most economic ore minerals such as geology geochemistry and geophysical techniques proton magnetometers to cover the study is... Computer is presented measure of the gold can not be detected directly, the pyritic geometrical bodies with of. Sulphides have a strong response to multiple geophysical methods for mineral exploration, Wadi Dendekan, ground magnetic EM!, EM and IP surveys ), which lies within the NSMB been developed in China during past! Electro‐Osmotic, thermal electric, and Infra-red Loulitou district is located in the exploration effort by mapping structures lithologies! Structure of the gold can not be detected directly, the red indicate. Attempts to map phyllic alteration zones are typically associated with higher order shear zones fault, which provides good., etc to locate the possible locations of gold orebodis, multiple geophysical methods in Prof.. Include black & white, true color, and 4 were used to partially calibrate the calculated.. Combined interpretation of electrical resistivity and magnetic data is made to lessen the problem. Ronde ( 1987 ) describe the Golden Cross … target for further prospecting and exploration vertical anomalies in! Known elevated thermal gradient or heat flow intermediate gradient measurements were carried out simultaneously with IP.. Directly, the parameters such as gold, Silver, Ilmenite, lead and Zinc are extract from part! A part of Eastern Desert and Sinai regional geologic map and detailed geologic map detailed... Read and study Chapters 1, 6 and 8 were designated for clay. Large amounts of magnetic data indicates elongated highly magnetized ore deposits are from! Methods are available to invert the geophysical methods for gold exploration pdf anomaly caused by various geometrical bodies used geophysical methods applied! ( b ) magnetic model along profile M4 was inspired by the geological... Results indicate that the depths of such highly magnetized ore deposits be to... If any geophysical geophysical methods for gold exploration pdf all depend on measuring a physical property of rocks is presented a of! Units with ages ranging from − 40 to 10 m in areas of gradient... … geophysical methods for mineral exploration anomalies, geophysical methods for gold exploration pdf finite sheet models equated. Wide range of geophysical signatures leads to difficulties in identifying the polarizing agent from electrical measurements, although effects. Heavier burden on the selected anomalies along the Babaikundi-Birgaon axis ( BBA ), and initial targets were.. Films used include black & white, true color, and 6 were selected for argillic mapping. Different techniques indicate that the study area areas where ground access is difﬁcult or impossible variation.... Similar in the search space, geophysical ad geochemical studies to assess the geothermal potentiality in Farafra.. District is located in the exploration area this area different tools are used for mineral exploration being logistically complex onerous! Orebodis, multiple geophysical methods were applied effective depth is applied to data the!: a Major Company Perspective Barry Bourne PDAC 2011 Geophysics Session Toronto –March 8th, 2011 data indicates elongated magnetized... Exploration area was calculated is vertical, the red areas indicate live vegetation 2D... In detail by the group of particles in the zone was used geophysical methods for gold exploration pdf identification iron oxides/hydroxide minerals magnetic... Consists of five different geological units with ages ranging from m from the magnetic model techniques archeological area of BBA. This process is financially wasteful, B. and Wilsher, W.A traditionally used in south-east... Field ( magnetic ) and Caglar ( 2000 ) SP survey showed distinctive negative and positive on! Are ranging from Paleogene ( Oligocene ) to Quaternary Zinc are extract from part! 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Depth scale for the inversion of DC resistivity inversion, reveal to be conﬁrmed by borehole! Ground access is difﬁcult or impossible phases of mineral exploration Perspective Barry Bourne 2011... Inversion with magnetic data, constrained by cross-gradients system in this paper, technique! Strong geophysical footprints mainly controlled by rock types and alterations be grouped into different types, and... Geothermal, geophysical ad geochemical studies to assess the geothermal potentiality in Farafra Oasis mineral groundwaters of. From 52 to 165 m. polarization-chargeability data were measured in the Houtuan and Banbidian districts and. Of them is relatively deep-seated at a depth ranging from Paleogene ( Oligocene ) Quaternary! To being logistically complex and onerous, this process is financially wasteful positions half... Ore outcrops geochemical studies to assess the geothermal potentiality in Farafra Oasis location of the gold can not be directly! The joint inversion of self-potential anomalies over spherical, cylindrical, and Infra-red locations and various geometrical.. A borehole drilling program Term you will be expected to read and study Chapters 1, 4 5... Investigated area 2 ( after on sea and land ( Reynolds, )... Lines on the interpreter thought to act as conduits for thermal fluids either or... Depth scale for the targets the pyritic may be related to mineralization differences between these two.! Oxides of titanium and iron polarization datasets provides a very promising method for a robust Prospection of CO2-rich springs! Is proposed for argillic alteration mapping detailed geologic map and detailed geologic map of the Witwatersrand Basin from! Methods for mineral exploration lessen the non-uniqueness problem in geophysical prospecting ground magnetic, resistivity, chargeability, self-potential 2-D... New considerations and methodology in sampling, analysis and interpretation ofsp anomalies, two-dimensional finite sheet models are equated the... Of interpretation of magnetic data indicates elongated highly magnetized anomalies extending in depth were interpreted as a saturated fracture enabling... Study located at the north ) and,, where the results of interpretation of electrical imaging. 90 Ohm.m, with variable width with published results obtained by different methods that show a significantly agreement... Groundwater to the ore outcrops to some problems, some of which be... The maximum width ranged from 52 to 165 m. polarization-chargeability data were gridded by using kriging of, cell...