The configuration parameters of the equipment were: 500mA, transmission time in 1s, beginning of readings after 0.2s cutting of current and reading residual voltage in 2 fixed windows and … 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. 62.3 m and maximum width ranging from 52.6 to 165.2 m. The low resistivity and high chargeability for the last part, of the dipole–dipole section ‘P1’ are well suited with the, dipole section from proﬁle ‘P2’ reveals low resisti, high chargeability at depths in the range of 35–60 m which. in the exploration for gold in South Africa should be orientated towards locating areas underlain by gold-bearing conglomerates of the Witwatersrand System. The electrical data is inverted in 2D along several profiles across the main favorable zones of Cu-bearing mineralization to image the electrical resistivity and chargeability properties. Gold and Silver Prospection Using Magnetic, Radiometry and Microgravity Methods in the Kıs¸ladag˘ Province of Western Turkey Ö. In this paper, SPCA technique is an appropriate method because of the distinction between alteration minerals and vegetation for Fe-Skarn mineralization exploration. The PSO algorithm was used to invert the SP data that, are crossing areas where geologic observations and magnetic, interpretation indicated that the ore body is represented by, ﬁrst parts of proﬁles SP1, SP2, SP3 and SP4 are shown in, ranges from 40.2 m at the proﬁle SP2 to 60 m at the proﬁles, Gradient resistivity and induced polarization (IP), electrode separation was ﬁxed at 50 m for the entire survey, and the stations were distributed evenly e, of high spatial resolution 50 m with good penetration depth, The surveys were carried out using a Syscal-R2. Two case 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 %%EOF
The price paid for this increased flexibility is a heavier burden on the interpreter. using a Syscal-R2 instrument using manual mode. 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. 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. The low-resistivity zones coincide with the altered and sheared acidic meta-volcanics. Improved satellite-, airborne - and field-based infrared spectroscopy has significantly improved alteration mapping around gold … The effective depths for various arrays are compared; the results agree with the traditional applications of each array. 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. Geol. By using deposit models, and with knowledge of the deposit characteristics that are important for providing measurable physical … 1 is dissected by a NE-SW trending Suppose a group of birds is searching for food in an area. Geophysical exploration … • Outcropping and near‐surface discoveries are now rarer. Application of these coefficients to a number of theoretical and field cases shows that they give reasonable results when applied to more complicated models. Shock waves are generated at a point on the … (b) Upward continued (60 m) self-potential (SP) anomaly map showing possible extension of a part of BBA. Geophysics tends to be used as a tool to follow-up in … Images are recorded either on films or by recording the image digitally. The quantitative interpretation technique determined the conductive bodies' parameters using the Schulz method (1985) where the depth to the top of the ore body ranged from 21 to 62 m while the maximum width ranged from 52 to 165 m. The induced polarization-chargeability data were measured in the time domain. 0
geological, remote sensing, and geophysical data were ����=fs�j�㝙���Ē��Cش��PF�� (Oligocene) to Quaternary. 2 contain The occurrences of gold and disseminated sulfides lie as a part of the shearing fault zone that extends from the north to the south of the study area for a length of about 25 km. The geoelectrical tomography survey was carried out to explore and characterize a (Zn-Pb-Ag) sulphide deposit in Nash Creek (NC), New Brunswick province, Canada. 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. The methodology provides good results at a very low cost when compared with drilling boreholes. For example, the magnetic ﬁeld of a narrow 2D dyke has a, using this index for the distribution and depths of the magnetic, ore bodies suggest that they are at a depth ranging from 20 to, The magnetic anomalies in the total intensity map tentatively, interpreted as originated by the shear and mineralized, using the Geosoft program (1998) and assuming a magnetic, susceptibility of 0.0775 cgs unit, ﬁeld strength is 40, the depth of magnetic source (ore body) appears to be ranging. volcanics are located at the eastern and western parts of the, study area which is characterized by dark grey colour and, are located at the northern and southern parts of the area, where these are characterized by greenish grey colour and, mineralized at the northeastern and southwestern parts of the, is mainly composed of quartz–feldspathic highly ferruginated, rock (gossans) occupying the eastern and central parts of the, which is distributed throughout the entire area and exhibits a. light grey colour with no mineralization. The datasets (resistivity and induced polarization) were acquired using the Iris El-Rec Pro system with pole-dipole electrodes array spaced 50 m apart, and ten levels of data datum. The mineralisation is structurally controlled and is associated with higher order shear zones. volcanoplutonic belt. Models and Exploration Methods for Major Gold Deposit Types Robert, F.  , ... For gold exploration, important geophysical advances include airborne gravity, routine 3D inversions of potential field data, and 3D modeling of electrical data. to the groundwater reservoir. The parameters of the sheet may be evaluated either geometrically or by using some analytical relations among the characteristic distances. concerning depths and locations of the magnetized bodies. Integration between the magnetic and geo-electrical data is made to lessen the non-uniqueness problem in geophysical prospecting. ... Geophysics is an alternative tool for either detecting new reserves or revaluating known deposits. Geophysical Exploration for Gold: A Major Company Perspective Jared Townsend*, Project Geophysicist – North America, Barrick Gold Exploration Inc. Barry Bourne, Chief Geophysicist – Global Exploration, Barrick Gold Exploration Inc. Barrick Gold Exploration Inc. 293 Spruce Road Elko, NV, 89801 Ph: +1 (775) 738 2062 Fax: +1 (775) 738 2804 Especially, to identify mineralization zones with a low-grade ore. One of the geophysical techniques that can be applied effectively for that is the geoelectrical technique (DCIP) (direct current (DC) resistivity and induced polarization (IP)) , ... Due to optimization in cost and time of mineral exploration programs, the application of geophysical surveys has recently been increasing in the shallow and deep-seated ore-bearing investigations. extensions through the structural shearing zone. In all the studied cases, the cross-gradient constraint appears to be a key-diagnostic tool to assess whether actual coherence is gained among DC resistivity and magnetic susceptibility models. Consequently, they exhibit a wide range of geophysical signatures. ... Subsurface investigation using both magnetic and DC resistivity data has regarded mining explorations (e.g., Farafra Oasis is one of the most interesting area that proposed to implement a proposal to exploit the geothermal resources. According to the integrated results, at least two suggested locations are recommended for drilling to confirm such results of mineral potential of the study area. seven potential electrodes of copper sulfate. The other instrument was used for ﬁeld measurements along, nine proﬁles through the surveyed area (ﬁgure. 10, – Google Scholar Corner, B. and Wilsher, W.A. the Abitibi greenstone belt; magnetic, EM and IP surveys), and to a smaller extent in Australia (e.g. 1. This leads to an absolute depth scale for the modified pseudosection. The predicted geological reserve of the sulphide ore in the exploration area was calculated. All figure content in this area was uploaded by Sultan A Araffa, The occurrences of gold and disseminated sulﬁdes lie as a part of the shearing fault zone. The theoretical basis, the computational algorithm, and applications of EULDPH to model and real data are presented.-Author, A method for quantitative interpretation of self-potential anomalies due to a two-dimensional sheet of finite depth extent is proposed. is a part of the Geosoft program package (1998). of W. Australia, Pub. shear zone which is composed of quartz–feldspathic, highly ferruginated rock (gossans) occupying the eastern, (2) The results of the magnetic interpretation indicated that, the depths of such ore deposits range from 35.9 to 52.7 m, and the half width ranges from 27.2 to 87.8 m, (3) The results of self-potential (SP) data indicated that the. In addition to being logistically complex and onerous, this process is financially wasteful. Abstract Conventional geochemical exploration for gold deposits has not always been very satisfactory, especially for buried and blind ones. Since the discovery of enormous new quantities of oil, gas, and sulphur has been by far and wide the principal benefaction of geophysics in the United States, this paper will refer only to geophysical methods employed in the search for these particular minerals. (a) Euler solutions, (b) magnetic model along profile M4. Magnetic … A third synthetic case involves a multisource model. Geophysical exploration for Precambrian gold deposits Download PDF EPUB FB2. In this way, Geophysics is an alternative and indirect investigative tool traditionally used in various phases of mineral exploration. 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. SP data were collected along 7 profiles at 10 m station interval with approximate profile separation of 100 m. The anomalies of possible ore bodies were found at depth of about 18–25 m using Euler deconvolution of SP data. • Our challenge is to explore covered areas, look deeper, and understand what we are seeing • New … an effective approach to characterize groundwater reservoirs. from 21 to 62 m while the maximum width ranged from 52 to 165 m. polarization-chargeability data were measured in the time domain. (a) Map showing profiles AA/, BB/, CC/ and DD/across the Babaikundi-Birgaon Axis (BBA). approaches zero as the structure approaches a horizontal sheet. This leads to difficulties in identifying the polarizing agent from electrical measurements, although the effects of well mineralized zones are easily recognized. Bands 7, 8, and 9 were nominated to specify propylitic alteration mapping. To examine the feasibility of the joint inversion algorithm, we first test the method with two synthetic cases: a thick dyke in a two-layered medium and a cavity located above a conductor. Titanomagnetite is a mineral composed of oxides of titanium and iron. 2 Overview Introduction Geophysics team Gold model types Examples Conclusions. These geochemical methods play a key role in gold exploration in Gansu, particularly during reconnaissance exploration. In this paper we perform a 2-D joint inversion of DC resistivity and magnetic data, constrained by cross-gradients. GEOPHYSICAL METHODS IN GEOLOGY Prof. G. R. Foulger & Prof. C. Peirce . Dipole--dipole induced-polarization measurements are commonly presented as pseudosections, but results using different dipole lengths cannot be combined into a single pseudosection. However, the results of the SP survey showed distinctive negative and positive anomalies ranging from − 40 to 10 mV. Seismic-Refraction Method: The seismic-refraction method is based on the principle that elastic shock waves travel at different velocities in different materials. Modern exploration methods Modern exploration methods --locating hidden goldlocating hidden gold paleochannels in the Cariboo Mining District BC CanadaMining District, BC, Canada. Self-potential (SP) map with measured points and, , where the results indicate that the depth of the bodies.
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite data was used to identify alteration zones associated with Fe-Skarn mineralization in the Ravanj village, Markazi Province, Iran. The passage of hot, saline, reactive fluids through volcanic rocks … The course text book is: An Introduction to Geophysical Exploration, by P. Kearey, M. Brooks and I. Hill, 3rd edition Blackwell Science, 2002, ISBN0632049294, cost new ~ £30. Important considerations for unconventional gold exploration in this paper are that (1) gold is … Hydrothermal alteration accompanying these deposits causes pronounced changes in the physical properties of the rocks. . the least-squares method Geoelectric Imaging 2D & 3D, investigation of gradient measurements in direct current, Siegel H O 1959 Mathematical formulation of type curves for, Sternberg B K and Oehler D Z 1990 Induced polarization in, hydrocarbon surveys: Arkoma basin case histories, Polarisation: Applications and Case Histories, ed S H Ward (USA: Society of Exploration Geophysicists), Thompson D T T 1982 Euler, a new technique for making computer, assisted depth estimates from magnetic data, LaBrecque D 1985 Direct detection of hydrocarbon, contaminants using induced polarization method, Prospecting for groundwater by induced electrical polarization, anomalies caused by spheroidal ore bodies, ere F 1998 Hydrothermal circulation beneath Mount, ... Worldwide, this integrated technique has been applied successfully at Squaw Creek, NW, British Columbia (Tomlinson, 1993), the Cariboo gold district and Antler Creek, central British Columbia (Gonzalez and Akhurst, 1988) for placer gold deposits. In the 1950s and 1960s, direct detection methods (chiefly airborne and ground electromagnetics (EM)) were applied widely in the search for massive sulphide-hosted base-metal deposits (Paterson, 1967). Therefore, the magnetic, self-potential SP, resistivity and induced polarization surveys were applied and critically interpreted at south Wadi Dendekan area to delineate the mineral ore deposits in terms of depths and extensions. 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. 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