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Integrated geophysical and geochemical study on AMD generation at the Haveri Au–Cu mine tailings, SW Finland
Abstract and Figures
The Haveri tailings area contains 1.5Mt of sulfide-bearing waste from the Au–Cu mine that operated during 1942–1961. Geophysical
and geochemical methods were used to evaluate and characterize the generation of acid mine drainage (AMD). Correlations were
examined among the electrical resistivity tomography (ERT) data, the total sulfide content and concentrations of sulfide-bound
metals (Cu, Co, Fe, Mn, Ni, Pb and Zn) of tailings samples, and the resistivity and geochemistry of surface water. The resulting
geophysical–geochemical model defines an area in the vadose tailings, where a low resistivity anomaly (<10Ohmm) is correlated
with the highest sulfide content, extensive sulfide oxidation and low pH (average 3.1). The physical and geochemical conditions,
resulting from the oxidation of the sulfide minerals, suggest that the low resistivity anomaly is associated with acidic and
metal-rich porewater (i.e., AMD). The lower resistivity values in the saturated zone of the central impoundment suggest the
formation of a plume of AMD. The natural subsoil layer (silt and clay) and the bedrock surface below the tailings area were
well mapped from the ERT data. The detected fracture zones of the bedrock that could work as leakage pathways for AMD were
consistent with previous geological studies. The integrated methodology of the study offers a promising approach to fast and
reliable monitoring of areas of potential AMD generation and its subsurface movement over large areas (ca. 9ha). This methodology
could be helpful in planning drill core sampling locations for geochemical and mineralogical analysis, groundwater sampling,
and choosing and monitoring remedial programs.
KeywordsTailings-Acid mine drainage-Sulfide oxidation-Electrical resistivity-Haveri-Finland
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... As for regime geophysical observations, they are not carried out on the vast majority of hydraulic structures located in the northern and northeastern regions of Russia, where permafrost soils are widespread (≈65% of the total territory of the country). An exception to the general rule is objects that are in the sphere of influence of PJSC (public joint-stock company) Alrosa and some foreign companies [11,12]. ...
... The resistivity of thawed rocks depends on the lithological composition, humidity and mineralization of pore moisture. The same parameters determine the resistivity of frozen rocks, but their temperature is the main factor [12]. In the study area, thawed technogenic soils (tailings) are widespread, which are represented by medium-and fine-grained sands, gravel, as well as alluvial sandy loams and weakly permeable, saline clays. ...
The relevance of the work is due to the risks of an uncontrolled increase in circulating water leaks through sides and bed of the dam, caused by thawing of permafrost soils in the Far North. The main aim of the work is to scientifically substantiate a set of engineering measures to reduce filtration consumption and restore and maintain the waterproofing of the tailing dump. The object of the study was the tailing dump of the concentration plant, with adjoining filter walls. The tailing dump has been exploited since 1996; for the last 20 years, circulating water leaks into the shunting tank located below were recorded. Within the water area of the tailing dump and at the landfalls, geophysical surveys were carried out from ice by the TEM (transient electromagnetic) method. The obtained geoelectric sections made it possible to form a holistic view of the structure of the filtration zones in the right and left bank junctions. The data obtained will be used for planning anti-filtration arrangement.
... 3.2.1 Geo-electric resistivity imaging section ASDAMI profile-1 The first group characterized by 5-61 Ohm-m resistivity is clearly delineated under this geo-electric imaging section interpreted as sand clay where the average depth extent varies from 1.25-24 erratically as shown in figure 9 topsoil, highly to moderately weathered tuff and fractured Ignimbrite where the registered average depth extent is 1-15 m. The second cluster with a median electrical resistance price of 140-319 Ohm-m electrical resistance response is understood as from extremely to moderately weathered\fractured Ignimbrite/basalt to a median depth of 8-24 at the sting the natural stream depression and pinch out at the stream natural depression floor (Hokkanen et al., 2010). The third cluster, with a median electrical resistance price larger than 729-1665 Ohm-m electrical IAEES www.iaees.org ...
The study area, Ankashasha dam site is found in South Nations, Nationalities and Peoples Regional state of Ethiopia. The overall objective of geophysical investigations in the study area is to assist geological studies to determine the depth of bedrock and estimate the probable seepage that might encounter dam reservoir areas. Vertical Electrical Sounding (VES) and two-dimensional electrical resistivity imaging survey methods were used to assess the safety of the Ankashasha dam. The data were acquired from four VES points using Schlumberger cathode arrays with supreme half current electrode spacing, and two-dimensional electrical resistivity imaging three profile data points were analyzed qualitatively and quantitatively to understand the geology and identify aquifer bearing horizons. The qualitative analysis of VES data was accomplished by using curves, apparent resistivity, pseudo-depths, and the quantitative interpretations of the VES data were constructed by the VES data using IpI-res3, IPI2win and Surfer software and constructing geo-electric section sideways profiles using the result from VES point interpretations and lithological information from the Bedesa borehole. The VES results of the data revealed three geoelectric layers that differ in degree of fracturing, weathering and formation. The bedrock is closer to the surface on the delineated fracture boundaries on the geo-electric section of the NE flanks of the axis. The overburden materials consist of seepage flow paths that widen northeastwards parallel to clay, sandy clay and clayey sand. Seismic refraction work should be forwarded since the area is seismically active to map the structures and determine parameters such as densities of eachlayer, weak zones, depth to contacts and others.
... A combination of geoelectrical surveys has been extensively and efficiently performed for a variety of purposes such as mineral exploration, water and pollution studies, engineering and geological research, and so on. Numerous applications include the description of polymetallic deposits (Yang et al. 2008), waste management in hydrocarbon studies (Cardarelli and Di Filippo 2009), porphyry ore-bearing mineralization (Flores and Peralta-Ortega 2009;Daneshvar Saein et al. 2012), metal exploration (Ramazi and Mostafaie 2013), water studies (Kozhevnikov et al. 2014;Madun et al. 2018), Au-Ag deposits (Gurin et al. 2015), characterization of bitumen deposits (Mashhadi et al. 2019), the study of pollutants from coal washing (Doulati Ardejani et al. 2008), Au-Cu mine tailings (Gomez et al. 2010), pollution studies (Jodeiri Shokri et al. 2016;López-González et al. 2019), identification of mineral alteration (Mashhadi and Ramazi 2018), archaeological studies (Allaia et al. 2007) and recently investigation of fault systems related to the building stones (Qarqori et al. 2012;Öğretmen and Şeren 2014). Electrical tomography has been used successfully in studies for marble, travertine, and granite building stones (Medeiros 1987;Medeiros and Lima 1990;Barker et al. 1992;Carruthers and Smith 1992;Grandjean and Gourry 1996;Grasmueck 1996;Silva et al. 2004;Porsani et al. 2006;Kadıoğlu 2008;Aydın et al. 2005;Billi et al. 2016). ...
Geoelectric surveys are among popular subsurface geophysical imaging techniques that
provide significant insights into the electrical properties of subsurface targets. In this research, geoelectric modeling of travertine deposits at the Atashkohe region in Iran is performed through discretizing the physical model domain through structured (quadrilateral) and unstructured (triangular) meshes. This meshing tool captures the accurate borders of a rugged topography area along with any complex-shaped travertine sources. The modeling process was accomplished through utilizing an open-source python-based software called “ResIPy”, which handles all processing steps necessary for reliable forward and inversion of geoelectrical data (i.e., electrical resistivity and induced polarization). Three synthetic electrical models according to the geological background of the studied area were simulated to examine the efficiency of the 2D electrical survey in imaging the travertine building stone. Two types of structured and unstructured meshing were designed to cope with the rough topography surface and any intricate geometry of subsurface target. The inversion results of the synthetic models approved the accuracy and efficiency of both geoelectrical survey and data modeling in travertine exploration. Finally, as a case study, tomography data of electrical resistivity and chargeability taken from the Atashkohe travertine mine were geophysically modeled to infer geological sections along three 2D profiles surveyed in the region. Data were collected with an electrode spacing of 15 or 10 m through a combination of dipole-dipole and pole-dipole arrays. The results of inverse modeling indicated that the provided geological and electrical sections at depth could be related to travertine lenses and further survey can help delineation of these building rocks. Comparison of electrical models and stratigraphic column obtained from two drillings along one profile showed a relatively good agreement as well.
... Geophysical methods, and in particular geoelectrical techniques have proved to be suitable tools for the investigation of dumps with the residues of mining and processing activities (e.g. Grissemann et al. 2007;Rucker et al. 2009;Anterrieu et al. 2010;Placencia-Gomez et al. 2010;Martin-Crespo et al. 2011;Martin et al. 2020). The application of the induced polarization (IP) method, which is an extension of the conventional resistivity technique, provides additional potential of ore minerals, which are characterized by high polarization effects (e.g. ...
Induced polarization (IP) is an acknowledged method in ore exploration and can be applied to evaluate the metal content in dumps containing the residues of ore processing facilities. Existing models explain the relationships between ore content and grain size of the ore particles with IP parameters. However, the models assume full water saturation of the ore containing samples, which is often not the case in field conditions at dump sites. Hence, our study investigates the effect of desaturation on the resulting IP signal. We used six different sand-pyrite mixtures with varying amount and grain sizes of the pyrite particles. Evaporative drying desaturated the samples. Complex conductivity spectra were recorded in the frequency range between 0.02 and 1000 Hz at certain saturation levels. The resulting spectra indicate an decrease of the conductivity amplitude with progressing desaturation. This effect agrees with the second empirical Archie equation. The saturation exponent of the conductivity amplitude shows values slightly larger than one. The measured spectra were processed by a Debye decomposition. We observe a nearly constant total chargeability during desaturation. This finding is in agreement with existing models that relate the total chargeability to the metal content in the sample. However, the mean relaxation time decreases remarkably during the drying process, whereas the normalized relaxation time, which considers the ratio between the mean relaxation time and the resistivity of the embedding material, does not indicate any dependence on water saturation. This behaviour contradicts existing models that predict a decreasing relaxation time with increasing water salinity, which results from evaporative drying. In order to explain the observed effects, we propose a conceptional model that compares a mixture of pyrite particles in an embedding material (sand, water, air) with an electrical RC circuit. The pyrite grains behave as small condensers that are charged and discharged via the conductive background material. According to this simple physical model, the relaxation time is proportional to the resistivity of the embedding material. A resistivity increase while desaturation causes an increase of relaxation time as observed in our experiments. This conceptional model is in good agreement with other experiments that change the resistivity in the background material by varying water salinity or clay content. The capacitive behaviour of the dispersed particles is characterized by the normalized relaxation time that depends on the grain size and the volume content of the pyrite particles.
... Over the past few years, various geophysical investigations using the spectral induced polarization (SIP) method at historical mining dumps or tailings have been conducted for archaeological or environmental reasons (e.g., Weller et al., 2000;Ullrich et al., 2007;Placencia-Gomez et al., 2010, 2015Florsch et al., 2011Florsch et al., , 2012Florsch et al., , 2017Martin et al., 2020b). Additionally, laboratory measurements have shown the high sensitivity of the SIP method to metal sulphides (e.g., Placencia-Gomez et al., 2013;Hupfer et al., 2016). ...
Historical slag dumps are of increasing interest due to economic, environmental or archaeological reasons. Geophysical investigations can help accessing the potential reuse of slag material to recover metallic raw material or the estimation of the hazard potential of the buried slag material due to dissolution occurrence.
In our study, we have investigated various slag material in the laboratory with the spectral induced polarization (SIP) method, obtained from different historical slag dumps, located in the Harz Mountains, Germany. We also present SIP results from field measurements at a historical slag dump where most of the slag samples reveal high amounts of iron, zinc, silica, and barium.
Our results reveal a discrimination between three different slag grades (low, medium, high) by using the imaginary conductivity σ” at a medium frequency (1–10 Hz) in both laboratory and field. Furthermore, additional information is obtained by a classification based on the spectral polarization behaviour and considering the field frequency range (0.1 Hz – 100 Hz). Five different types of spectra (ascending, descending, constant, maximum and minimum type) can be discriminated and recognized in the laboratory and in distinct areas of the slag dump. Even though a direct comparison between the laboratory and field results still needs to be proven, the buried slag material can be differentiated from the surrounding material by the polarization magnitude.
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We review the application of the Spectral Induced Polarization (SIP) imaging method to delineate the geometry of hydrocarbon contaminant plumes and monitor the effect of remediation measures. In the first two sections, we present a brief introduction into the SIP method and discuss the electrical properties of the rocks and soils. In the third section, we offer a detailed revision of the literature to illustrate the broad range of electrical properties of fresh and mature contaminant plumes. In the fourth and fifth section, we discuss challenges and good practices for collection, processing and interpretation of SIP imaging data, and illustrate these steps with a real-case example regarding the characterization of a benzene plume. Along this case study, we demonstrate how the occurrence of benzene in the dissolved plume and in free-phase changes the electrical conductivity and polarization properties of the contaminated subsurface materials. A second case study deals with SIP monitoring results obtained along the injection of zero-valent iron particles for the remediation of a TCE (Trichloroethylene) plume. This example illustrates the advantages of the SIP method to evidence changes in the pore-space, such as clogging and fracking, which may affect the effectivity of remediation measures.
Two geophysical field works were conducted during a feasibility study in the Smaltjärnen tailing repository of the abandoned Yxsjöberg mine, located in south-central Sweden. The aim of these studies was to evaluate the applicability of the geophysical methods in tailing characterizations i.e. to (I) identify the approximate level of the underground water table, (II) understand the vertical and lateral distribution of the tailings and (III) image the variations within the internal stratigraphy of the tailings. Ground Penetrating Radar (GPR) data with medium–low-frequency antennas (300, 250 and 100 MHz) and Self-Potential (SP) data using the Streaming Potential Phenomena (SPP) were collected to characterize the top few meters of the subsurface and understand the water flow direction. Results from the mineralogical and geochemical studies of the drill-core samples were incorporated in the study to complement the interpretations of the geophysical data. Three distinct layers had been earlier identified based on the interpretations of the geochemical data which agreed well with the GPR interpretations in this study: (I) oxidized tailing (new), (II), transition zone and (III) old tailing which is located under the water table. The SP data, unexpectedly, indicated that the groundwater flows from the lake i.e. lower altitudes, towards the higher altitudes which probably is related to the uncertainties resulted from 2D data while the actual water flow direction can be best studied in 3D, or, dominant effect from the metal contents. Complementary geophysical studies including a 2D-SP survey and Direct Current (DC) electrical resistivity measurements are suggested to improve the present understanding of the morphology of the site.
The study area is located in the old mining district of Linares–La Carolina (southeastern Spain), the largest global producer of lead between 1875 and 1920. The selected environmental liability is the dam of the Federico mine and the waste that was generated during the flotation process. Geophysical techniques were applied along the slope of the dam, specifically ERT and IP. In total, 26 waste samples were taken along the entire slope of the dam, in which a high metal(oid) content was identified, sometimes much higher than the reference levels established by European and regional legislation for contaminated soils. The concentrations of Pb, As, and Ba stood out, with mean values of 4863 mg.kg−1, 89 mg.kg−1, and 794 mg.kg−1, respectively. Univariate and multivariate statistical analysis could characterize the distribution of the contents of the different elements along the slope, defining the associations and dispersion patterns of the metal(oid)s in the interior structure of the mine wastes. With the results of the Pb content (the most abundant metal in mineral paragenesis), a mathematical model was obtained by linear regression that related the variability of this cation with the variation in electrical resistivity and chargeability obtained by geophysical techniques.
During its 13 years of non-continuous operation, the Osamu Utsumi Mine has generated serious environmental impacts. This mining complex is now attempting to decommission this uranium mine to reduce its environmental liabilities. As part of a hydrogeological analysis of the old Osamu Utsumi Mine pit area, a geophysical investigation was carried out along each front of the mine pit using electrical resistivity tomography and a dipole–dipole array. The lithology described in each front, the physical access, and data from monitoring wells also contributed to the geophysical interpretation and, hence, the hydrogeological analysis. The field results and geochemical data from monitoring wells enabled us to distinguish areas where water was flowing through fractures in the massif and areas with more acidic water, with electrical resistivity values less than 15 Ω m.
The extinct Haveri Au-Cu deposit is located within mafic metalavas and mafic/intermediate banded rocks of the Haveri Formation in the western part of the Paleoproterozoic Tampere Schist Belt. The sulfide-bearing banded rocks display a large E-W trending fold structure in magnetic and electromagnetic maps. Field evidence suggest that the Au-Cu deposit is in a F1/F2 fold interference pattern in the western core of the large fold. The ore-forming elements concentrated into the F1 fold closure during D1 deformation. Sulfide-bearing fractures subparallel to S2 spaced cleavage indicate slight remobilization during D2. -Author
The industrial waste land in Mortagne-du-Nord (France) has been the site of a zinc smelter Unit and a lead smelter unit linked to sulphric acid production. It has been systematically explored by drillings and pits. Geophysical data have led to the location of mineralized soil and water, and to the identification of water seepage towards file river drain. various geophysical devices are used for subsurface exploration and for studies with higher spatial resolution. The prospect area covers a surface of 4.5 ha. Data obtained from trenches has been Used to calibrate and to validate file geophysical interpretation. It has been found that variations in the depth of the interface between resistive and conductive layer, are due to two types or waste: 'non-active' (carbonates and oxides) and 'active' (sulphides and sulphates) materials. Lower resistivities than expected are due to the presence of mineralized water in all geological formations.
We've used direct current resistivity (DC), electromagnetic (EM), induced polarization (IP), and ground-penetrating radar (GPR) geoelectrical methods to study mine dumps. The results reflect lithology, pore water saturation, and dissolved solids in the pore water. If the pore water has a pH less than 5, conductivity maps can indicate acid generating potential. IP measurements can help distinguish mineralogy in mine dumps, especially concentrations of sulfide minerals. EM and DC can help locate acidic/high TDS groundwater associated with mine dumps. GPR methods failed at the sites we studied in the West. Our own conclusions are augmented by those from the recent literature. OVERVIEW A standard general reference on mine waste geophysics is the work of Custis (1994). Other references on mine waste geophysics, containing many instructive examples and good bibliographies, are by King and Pesowski (1993), Patterson (1997), and Campbell et al. (1999). A standard reference on using geophysics for landfills (not necessarily mine dumps, though much of the advice given therein applies to mine dump problems) is by Benson et al. (1983), with a good recent update by Greenhouse et al. (1998). Over the past three years, our group at the US Geological Survey has used direct current resistivity (DC), electromagnetic (EM), induced polarization (IP), and ground-penetrating radar (GPR) geoelectrical methods to study mine dumps. We have also reviewed post-1994 literature on the subject. This report summarizes what we have learned, and is intended as an update to the manual by Custis (1994). BRIEF DESCRIPTIONS OF SOME GEOELECTRICAL METHODS Table 1 lists some major geophysical methods, the physical properties they measure, and their optimal application for mine waste studies. In this report we focus on geoelectrical methods, those that measure electrical conductivity or resistivity. We do so because mine dump material is typically more conductive than host material, and because ground containing effluents with high amounts of total dissolved solids (TDS) and/or acid mine drainage (AMD) is more conductive than ground containing normal pore waters. The conductivity of a geologic unit, in general, reflects its lithology, its porosity, and the saturation and conductivity of its pore water. A unit containing conductive minerals, such as clays (e.g. montmorillonite) or sulfides (e.g. pyrite) will be more conductive than one consisting of silicate minerals. A unit consisting of crushed rock (e.g., most mine dumps) will have higher porosity than uncrushed host rock; this means potentially higher pore water content to carry electrical currents through the unit. The moister a formation is, the higher its conductivity is likely to be. Similarly, increased amounts of dissolved solids and of acid in its pore water will also increase the conductivity of a formation. Figure 1 illustrates the effect of acid, showing that for pH values less than about 5, the conductivity of mine leachate waters is inversely proportional to pH. Usually the conductivities of leachate waters and pore waters are similar. To move from pore water conductivity to formation conductivity, measured geoelectrically, one must divide by a so-called formation factor that depends on the lithology of the formation. Typical formation factors fall in the range from S to 20. This suggests that in dumps that are fairly uniform and generally moist, and as long as the pH of the pore water is S or less, a conductivity map might help
The authors have carried out a geophysical investigation on a waste rock pile at the Laronde gold mine (Agnico‐Eagle Ltd, Quebec). GPR, low‐induction number EM and 2D resistivity tomography measurements have been conducted during consecutive field surveys in 2002 and 2003 on top of the pile to map its internal structure. Repeated infiltration tests and geophysical monitoring from ground surface have also been performed to map preferential flow paths. Using the field data, the authors propose here a three‐layer model for the first 5–6 m of the pile, mainly based on electrical conductivities. Electrical conductivity increases with the degree of oxidation of the sulphidic minerals contained in the waste rock. The contact between unoxidized‐oxidized waste rocks is typically marked by a well‐defined resistive‐conductive boundary, as shown by digging a 2.5 m‐deep trench. Integration of geophysical and hydrogeological information indicates that there is a lateral conductivity variation, which may be due to the deposition method, mechanical alteration caused by machinery, and by increased oxidation of sulphides near the external boundary of the pile. GPR monitoring during infiltration tests seems to indicate preferential flow paths towards a zone of low sulphide content materials and low oxidation by‐products. The resistivity and GPR methods appear to be efficient geophysical methods to characterize the internal structure of the Laronde waste rock pile.
The aim of this research was to investigate the effect of waste from a mine dump on the surrounding soils and groundwater. The study area is underlain by high-grade granite gneisses with shallow weathering. Hence, the groundwater occurs in an open aquifer system and is likely to interact with surface runoff. This could result in pollution of the groundwater and the Motloutse sand river aquifer into which the streams flow. Geophysical investigations of the effect of the mine waste on the subsurface conditions was carried out using 2-D resistivity and electromagnetic techniques. The results of the 2-D DC resistivity survey showed portions of the top layer of low to moderate resistivities (between 1-20 Ωm), suggesting that the low resistivities in this layer might be as result of interaction of the mine waste with the soil. The EM profiles show that around the stream channels, conductivities are higher than outside the streams. Since the stream originates near the dump, leachates from this mine waste are transported by water and deposited along the stream with some of the leachates infiltrating into the ground.
Acid mine drainage (AMD) results when sulphide bearing tailings sand is exposed to air and water. Oxidation of sulphide minerals and release of acid and dissolved metals in tailings impoundments can last for tens to hundreds of years. Rehabilitation, risk analysis and risk assessment of the old tailings impoundments require detailed information on the structure, mineralogy and chemistry, as well as on the hydrology of the site. To develop methods for characterizing the tailings impoundments, related dam constructions and underlying soil and bedrock structures a series of ground electromagnetic (EM), electrical resistivity, gravity and refraction seismic data were made over an old tailings sand impoundment at the closed Hammaslahti Cu mine, Eastern Finland. In addition to geophysical data, mineralogical studies and a comprehensive drilling and analysis program has been carried out.