Anomalous Areas Research Articles

The Delineation of Copper Geochemical Blocks and the Identification of Ore-Related Anomalies Using Singularity Analysis of Stream Sediment Geochemical Data in the Middle and Lower Reaches of the Yangtze River and Its Adjacent Areas, China

The middle and lower reaches of the Yangtze River and its adjacent areas contain abundant mineral resources, especially porphyry–skarn–stratabound Cu–Au–Mo–Fe deposits, and still have great potential for mineral prospecting. In this paper, geochemical blocks and local singularity mapping methods were used to delineate the spatial distribution pattern of Cu and identify the geochemical anomalies related to Cu deposits. Six copper geochemical blocks, each with an area of more than 1000 km2, were all spatially consistent with the locations of the five Cu ore districts (Edongnan, Jiurui, Anqing-Guichi, Tongling, and Ningzhen) and one ore field (Dexing) in the study area. Thus, geochemical blocks delineated with low-density geochemical data can effectively track the locations of ore districts or large ore deposits. Most of the known Cu deposits in the study area were located in anomalous areas with singularity indices less than 1.741 in the Cu singularity map. The singularity analysis could reduce the anomalous areas and identify the geochemical anomalies related to Cu deposits effectively. Geochemical blocks combining a local singularity mapping method is an effective tool for identifying prospecting targets.

Spatio-temporal variations of aerosol optical depth over Ukraine under the Russia-Ukraine war

The ongoing Russia-Ukraine war has an impact on air quality in the contested region, but it is difficult to assess it during the war and to distinguish between weather conditions and anthropogenic impacts on air pollution. Aerosol optical depth (AOD) might be a way to indicate the regional air quality remotely. In this study, we analyze satellite-based MODIS Multi-Angle Implementation of Atmospheric Correction (MAIAC) AOD products to compare monthly mean AOD values before and during the war. By examining the spatial-temporal distribution of AOD in 2022 and comparing it with a baseline period from 2012 to 2021, we aim to assess the impact of the conflict. Our analysis employs a time series algorithm that decomposes long-term trends and seasonal variations, enabling us to identify AOD changes associated with the war-induced artificial perturbations. Additionally, we utilize satellite-based tropospheric NO2 data and nighttime lighting data as auxiliary sources to support the analysis of abnormal AOD changes resulting from the war. Furthermore, four parameters from Aerosol Robotic Network (AERONET) measurements in the Kyiv site, including angstrom exponent (AE), single scattering albedo (SSA), refractive index (RI), fine mode fraction (FMF) were exclusively discussed to explore the possible changes of aerosol physical-optical properties over Ukraine during the war. Results showed that air quality in Ukraine has been affected by the war in contradictory ways at different levels. At the national level, atmospheric pollution has dropped across Ukraine due to a decrease in the sources of air pollution emissions as a result of the suppression of economic and agricultural activities. Meanwhile, atmospheric air quality has deteriorated at the local scale where war is intense due to the large amounts of air pollutants emitted by explosions. Specifically, a significant decrease in AOD of 22.46% compared to the baseline period was observed across Ukraine in January and February 2022 before the war. Additionally, there was a column density reduction of over 10% for tropospheric NO2 compared to the same period in the previous year. Following the outbreak of the war on February 24, significant increases in AOD were observed in March when compared to the baseline period. Eastern Ukraine experienced a significant increase of 40.14%, while northern Ukraine and central Ukraine saw rises of 34.15% and 45.78%, respectively. In April, a wider distribution of areas with significantly high AOD values across Ukraine was observed compared to March. In July, widespread areas with anomalous low AOD appeared in northern and western Ukraine, likely due to a decrease in post-harvest agricultural burning caused by the war. In August, anomalous high AOD areas were observed in central Ukraine, possibly attributed to continued Russian long-range strikes and a new round of bombardments.

Identification of geothermal potential based on land surface temperature derived from remotely sensed data.

With the continuous development of thermal infrared remote sensing technology and the maturation of remote sensing inversion algorithms based on surface temperatures, identifying high-temperature anomalous areas by inverting surface temperatures has become an crucial approach to finding geothermal potential areas. The eastern region of Longyang in western Yunnan Province is renowned for geothermal resources, though the distribution area of geothermal potential remains unknown. Therefore, this study used Landsat-8 TIRS data and four surface temperature inversion algorithms, namely, mono-window algorithm, single-channel algorithm, Du split window algorithm (SWD), and Jiménez-Muñoz split window algorithm (SWJ), to explore the astern region of Longyang. The inversion results were compared with Moderate Resolution Imaging Spectroradiometer Land Surface Temperature (MODIS LST) results for analysis and cross-validation to select the optimal algorithm. A multi-view remote sensing temperature anomaly information extraction method was adopted. Moreover, the overall threshold method, the fracture structure buffer method, and the joint analysis of diurnal temporal data were combined for the reduction of the thermal anomaly area as well as for comprehensively defining the geothermal prospective area in the study area. The results demonstrated that the mono-window algorithm had the highest accuracy with a Pearson coefficient of 0.77, which is more suitable for the surface temperature inversion in Longyang area. Furthermore, three geothermal anomalies (A, B, and C) were identified in the study area, with larger thermal anomaly in A and C, but a smaller one in B. All three areas had hot spring points verified, with A and C exhibiting more significant development potential. The research results provide a reliable methodological basis for the development of geothermal resources in the region.

Singular Points of the Tremor of the Earth’s Surface

A method for studying properties of the Earth’s surface tremor, measured by means of GPS, is proposed. The following tremor characteristics are considered: the entropy of wavelet coefficients, the Donoho–Johnston wavelet index, and two estimates of the spectral slope. The anomalous areas of tremor are determined by estimating the probability densities of extreme values of the studied properties. The criteria for abnormal tremor behavior are based on the proximity to, or the difference between, tremor properties and white noise. The greatest deviation from the properties of white noise is characterized by entropy minima and spectral slope and DJ index maxima. This behavior of the tremor is called “active”. The “passive” tremor behavior is characterized by the maximum proximity to the properties of white noise. The principal components approach provides weighted averaged density maps of these two variants of extreme distributions of parameters in a moving time window of 3 years. Singular points are the points of maximum average densities. The method is applied to the analysis of daily time series from a GPS network in California during the period 2009–2022. Singular points of tremor form well-defined clusters were found. The passive tremor could be caused by the activation of movement in fragments of the San Andreas fault.

Rapid imaging approach for marine controlled-source electromagnetic with deployed transmission system

The marine controlled-source electromagnetic (MCSEM) method is widely used in gas hydrate exploration. For the deployed transmission system of MCSEM, it is equipped with two groups of orthogonal transmission antennas to obtain more comprehensive information. The mainstream processing method involves using a single rotated field component for conventional 2D inversion to obtain the resistivity model. However, data preprocessing and inversion speed are relatively slow, making it difficult to quickly or nearly real-time identify gas hydrate anomalous areas. In order to leverage the benefits of multi-component data and obtain a potential real-time imaging method for the future, we have developed a rapid imaging technique for the deployed transmission system to obtain apparent resistivity pseudosections. The current and electromagnetic field data in different directions are replaced by rotational invariants, and an approximate formula is derived based on the half-space formula and test corrections. This formula maps the apparent resistivity and field data. Results from model tests demonstrate that the apparent resistivity pseudosections can qualitatively identify reservoirs, particularly in the lateral range. In 2015, the South China Sea gas hydrate exploration project acquired data using the deployed transmission system. The pseudosections reveal that the rapid imaging method can directly detect resistivity anomalies and serve as an approximate and effective display method for deployed transmission system of MCSEM, thanks to its simplicity, efficiency, and low computational cost.

Development of normalized acoustic response analysis for soil-structure contact state evaluation

Abstract: Introduction. Impulse response testing is currently one of the most common methods of acoustic express diagnostics of the foundation slabs and other plate-like structures state, but is relatively uncommon in the Russian Federation. A modification of this technique, based on the analysis of normalized response parameters, is being actively developed by Russian specialists to assess the quality of soil-structure contact. The issue of developing of the new informative parameters and criteria for identifying of anomalies associated with contact violations is topical.
 Aim. The purpose of the work is to inform specialists about the capabilities of the normalized acoustic response analysis method for localizing zones of soil-structure contact violation. It is proposed to apply the attribute "void index" and an auxiliary criterion for data analysis based on the nature of the distribution of attribute values.
 Materials and methods. The features of the normalized acoustic response testing metodologia for soil-structure contact violations searching are described. The method for calculating the attribute "void index" for the data of the technique is shown. A criterion for the selection of anomalous areas is proposed, based on the data analysis of the nature of the distribution of attribute values.
 Results. Verification of the "void index" attribute application for searching for zones of soil-structural contact violation is shown on the results of a survey of a tunnel liner physical model with a known position of the void. An example of the results of a survey of a slab at the base of an underground car park shows the use of a "void index" in conjunction with the normalized signal energy attribute. A method for statistical processing of the results is proposed, which supplements the traditionally used "three sigma" criterion. 
 Conclusions. A method of the "void index" attribute application to localize zones of soil-structure contact violation for the normalized acoustic response analysis method is shown. A method for statistical data processing is proposed, considering the nature of the distribution of response attributes.

Recognition of multivariate geochemical anomalies using a geologically-constrained variational autoencoder network with spectrum separable module – A case study in Shangluo District, China

This study has developed a novel variational autoencoder architecture by incorporating the spectrum separable module, termed SSM-VAE, so as to recognize the multi-mineral-species geochemical patterns over the Shangluo district, central China, and then facilitate a better understanding of the regional metallogenesis. The primary advantage of SSM-VAE is its ability to explore the interlayer correlations and then integrate them into the reconstructed features, which greatly improved the geological interpretability of the model products. In the training process, a hybrid loss function with a geologically-constrained term derived from the fractal analysis was designed to guide the model to focus on anomalies related to mineralization. Afterward, the factor analysis together with the EM-MML thresholding algorithm were integrated as a post-processing tool. Finally, the mineral-spot identification rate (δ) versus the size of the anomalous area (S) are used to validate the ore-bearing potential of different anomaly divisions. Comparing to other state-of-the-art models without regard to the interlayer correlations, SSM-VAE can produce well-zoned, mineral species-specific, and more metalliferous anomalous patches. To be specific, we separated out 10 zoned anomaly divisions, and on average, when S = 1% there are 8.5013 mineral spots falling within.

Delineation of Integrated Anomaly with Generative Adversarial Networks and Deep Neural Networks in the Zhaojikou Pb‐Zn Ore District, Southeast China

AbstractGeochemical maps are of great value in mineral exploration. Integrated geochemical anomaly maps provide comprehensive information about mapping assemblages of element concentrations to possible types of mineralization/ore, but vary depending on expert's knowledge and experience. This paper aims to test the capability of deep neural networks to delineate integrated anomaly based on a case study of the Zhaojikou Pb‐Zn deposit, Southeast China. Three hundred fifty two samples were collected, and each sample consisted of 26 variables covering elemental composition, geological, and tectonic information. At first, generative adversarial networks were adopted for data augmentation. Then, DNN was trained on sets of synthetic and real data to identify an integrated anomaly. Finally, the results of DNN analyses were visualized in probability maps and compared with traditional anomaly maps to check its performance. Results showed that the average accuracy of the validation set was 94.76%. The probability maps showed that newly‐identified integrated anomalous areas had a probability of above 75% in the northeast zones. It also showed that DNN models that used big data not only successfully recognized the anomalous areas identified on traditional geochemical element maps, but also discovered new anomalous areas, not picked up by the elemental anomaly maps previously.

Favourable IOCG and polymetallic environs in Marwar - Khetri, NW Indian Shield imprints from aerogeophysical data analysis

The analysis of aeromagnetic data reveals two significant broad oval-shaped aeromagnetic anomalies oriented in the NE-SW direction, west of Laxmangarh and east of Fatehpur. These significant anomalies identified beneath sand-alluvium-covered areas of Rajasthan's Marwar region are of a low dominance nature. These magnetic signatures are associated with gravity gradients in the regional Bouguer gravity map. Magnetic anomalies and subsurface modeling revealed that the remanence source had a high magnetic susceptibility. The ground gravity profiles across the Laxmangarh anomaly show a high gravity variation of 5 mGal/km. The integration of geochemical distribution patterns, spectrometric elemental concentrations, different ratios, and composite image maps has brought out alteration/shear zones that are favourable for mineralization. The results of selective 2D-profiles, plate modeling, and 3D-inversion modeling of these anomalies reveal that the depth of the causative source varies from 300 to 1000 m. The higher-order magnetic susceptibilities, geochemical dispersion pattern, and spectrometric ratio maps and composite images distinguished hydrothermal alteration zones characterised by potassium enrichment. The results indicate the possibility of concealed source rocks with high magnetic mineral content (magnetite, maghemite, titanomaghemite, pyrrhotite, and franklinite?) and a relatively high density. The geophysical signatures observed around Fatehpur and Laxmangarh, with high magnetic contrast, low dominance, and remanence coupled with high gravity values, as well as hydrothermal alteration zones, appear to have striking similarities with the geophysical and geochemical scenarios of some of Australia's Iron Oxide Copper-Gold (IOCG) prospects in the Gawler, Arunta, Tennant, and Mount Isa regions. Therefore, these anomalous areas may be explored for the possibilities of an IOCG or polymetallic type of mineral.

Development of the renewable geothermal energy in Uzbekistan (as an example – the Muruntau area)

This paper presents a Multidisciplinary geophysical study of the geothermal areas in Uzbekistan. Based on the developed new geothermal map, data on anomalous geothermal areas were analyzed. Based on the study of the Muruntau area, a comprehensive methodology has been developed for detailing geothermal anomalies. New data of integrated geophysical surveys (gravity survey, seismic survey, magnetotelluric survey) and their interpretation at the stage of geophysical exploration are presented.

Experience of amplitude-frequency estimation of ground vibrations in the range of 0,05–0,5 Hz using the sensing element of the GNU-KV gravimeter

Background. The responsive element of the GNU-KV Russian gravimeter comprises a Golitsyn lowfrequency vertical seismograph, which outperforms modern industrial SM-3KV seismographs in terms of sensitivity to ground vibrations. A team of geophysicists at the Sergo Ordzhonikidze Russian State University for Geological Prospecting modified the construction of GNU-KV to adapt this device to work in the mode of a portable seismological station for recording natural seismic vibrations in the frequency range of 0.05–0.5 Hz. Given the equivalence of gravitational and inertial fields, the presented technology is capable of not only detecting low-frequency ground vibrations, but also estimating accelerations and amplitudes of ground displacement at these frequencies.Aim. To investigate the capabilities of the GNU-KV gravimeter for recording and estimating the amplitude of ground vibrations in mm and mGal.Materials and methods. The proposed method for determining the anomalous areas of increased ground vibration using a GNU-KV gravimeter was tested in two geographical sites: in the vicinity of the Educational and Laboratory Complex of Sergo Ordzhonikidze Russian State University for Geological Prospecting and in the area of the RUDN University near a subway tunnel.Results. When determining the amplitude of ground vibrations in mm and their acceleration in mGal, the conversion coefficient for the results of a digital signal obtained by GNU-KV and inertial accelerations in mGal was determined.Conclusion. The conducted studies confirm the capabilities of the GNU-KV gravimeter for the quantitative estimation of ground vibrations.

Anomalous Behavior Detection with Spatiotemporal Interaction and Autoencoder Enhancement

To reduce the cargo loss rate caused by abnormal consumption behavior in smart retail cabinets, two problems need to be solved. The first is that the diversity of consumers leads to a diversity of actions contained in the same behavior, which makes the accuracy of consumer behavior identification low. Second, the difference between normal interaction behavior and abnormal interaction behavior is small, and anomalous features are difficult to define. Therefore, we propose an anomalous behavior detection algorithm with human–object interaction graph convolution and confidence-guided difference enhancement. Aiming to solve the problem of low accuracy of consumer behavior recognition, including interactive behavior, the human–object interaction graph convolutional network is used to recognize action and extract video frames of abnormal human behavior. To define anomalies, we detect anomalies by delineating anomalous areas of the anomaly video frames. We use a confidence-guided anomaly enhancement module to perform confidence detection on the encoder-extracted coded features using a confidence full connection layer. The experimental results showed that the action recognition algorithm had good generalization ability and accuracy, and the screened video frames have obvious destruction characteristics, and the area under the receiver operating characteristic (AUROC) curve reached 82.8% in the detection of abnormal areas. Our research provides a new solution for the detection of abnormal behavior that destroys commodity packaging, which has considerable application value.

SAR Interferometry Data Exploitation for Infrastructure Monitoring Using GIS Application

Monitoring structural stability in urban areas and infrastructure networks is emerging as one of the dominant socio-economic issues for population security. The problem is accentuated by the age of the infrastructure because of increasing risks due to material deterioration and loss of load capacity. In this case, SAR satellite data are crucial to identify and assess the deteriorating conditions of civil infrastructures. The large amount of data available from SAR satellite sensors leads to the exploitation and development of new GIS-based procedures for rapid responses and decision making. In recent decades, the DInSAR technique has been used efficiently for the monitoring of structures, providing measurement points located on structures with millimeter precision. Our study has analyzed the behavior of structures in settlements, attempting to discuss the interactions of soil and structures, and examining the behavior of different types of structures, such as roads and buildings. The method used is based on long-term SAR interferometry data and a semi-automatic procedure to measure the displacement (mm/year) of structures, through a GIS-based application performed in the “Implemented MOnitoring DIsplacement” I.MODI platform. The analysis provides extensive information on long-term spatial and temporal continuity of up to 25 years of record, using satellite SAR multi-sensors from ERS, Envisat, and COSMO-SkyMed. The interpretation uses time series spatial analysis, supported by orthophotos, and layers of the DBTR (regional topographic database), Digital Surface model (DSM), and hydrogeological map to show anomalous areas with a high displacement rate and to observe the correlation of settlements in the sediments. With the satellite information and Geographic Information System (GIS), we were able to observe relevant parameters, such as the velocity of advance in the direction of the slope (deformation profiles), the cumulative displacement, and the trend changes in structures. The results illustrate an innovative procedure that allows the management of DInSAR data to facilitate the effective management of structures in which a monitoring protocol was developed at different spatial scales, integrating the information into a GIS.

Results of geophysical research on the Zmiyinyy island

The article presents the results of geophysical observations by the Dnepropetrovsk geophysical expedition «Dneprogeofizika» on Zmiyinyy Island, which performed a full cycle of work from prospecting and surveying studies to providing the island with drinking water.
 In structural and tectonic conditions, the island is considered as the Zmiyinyy insular block of the Danubian horst megablock. The geodynamics of the region is determined by the position and inclination of the collision sutures within the zone of interaction between the Eurasian and African lithospheric plates. Comprehensive geological and geophysical studies included magnetic prospecting, gravity prospecting and electric sounding (Dipole-axial sounding induced polarization DAS-IP) with geological routes along all rock outcrops on the Zmiyinyy island. Detailed integrated geophysical studies were: gravimetric observations over a network of 20×10 m, magnetometric — 10×5 m and electrometric (DAS-IP) — 40×5 m. For the first time on the island, gravimetric stations were set up, which will later become a support for gravimetric surveys. According to the results of magnetic field survey and DAZ-OP electrical exploration observations, an anomalous area was identified, which is perspective for archaeological research. Based on a comprehensive interpretation of geological and geophysical materials, a well was drilled to a depth of 120 m, which confirmed the constructed predictive stratigraphic section of about. Zmiyinyy. Based on the results of the search for sources of drinking water, three wells were drilled, with a fresh water flow rate of up to 10 m3 per day (each). Subsequently, fresh water with minor purification is used as drinking water.

The Unprecedented Duration of the 2020 Ozone Depletion in the Antarctic

An increase in the duration of the period of high stability of the Antarctic polar vortex in late spring and early summer (November–December), which has been observed over the past 30 years, is observed. This trend is manifested both in the dynamics of the main characteristics of the polar vortex (vortex area and wind speed along the vortex boundary) and in the area of the Antarctic ozone hole. The dynamics of the polar vortex of 2020 is clear evidence of this phenomenon. During that time, unusually high wind speeds along the vortex boundary were recorded throughout the entire period of its existence; anomalous areas of the vortex and the ozone hole were observed from mid-November to December. In addition, the polar vortex existed until the last week of December, which is unprecedented. To analyze the dynamics of the Antarctic polar vortex, we used the method of vortex delineation on the basis of geopotential values, which were determined from the maximum temperature gradient and the maximum wind speed characterizing the boundaries of the vortex.

Regional geochemistry of mercury in the Sino-Mongolian border region

The Sino-Mongolian border region is a hotspot for international geoscience research and exploration. Mercury (Hg) can be used as a reference element for geochemical exploration and ore prospecting. This is because the change in Hg concentration and its spatial distribution can indirectly reflect the regional mineral distribution and regional environmental mercury pollution. Hg pollution caused by anthropogenic activities has received extensive attention because of its hazardous nature and Hg is generally regarded as a global pollutant. Although geochemical explorations have been conducted in the Sino-Mongolian border region, there have been relatively few studies with detailed and consolidated analyses of single elements such as Hg. To address this research gap we have examined the concentration and spatial distribution of Hg in this region. Influencing factors including the geological background, geomorphological landscapes, mineral distribution, development and use, and human activities, were also explored. The Hg concentration in the catchment sediment samples had a median value of 16.5 ng/g considered the geochemical background value, mean value of 18.9 ng/g, and a range of 0.5–712.5 ng/g. Low Hg concentrations are distributed in the Gobi Desert areas of Xinjiang, Inner Mongolia in China, and in the southern Gobi region of Mongolia because of the poor adsorption capacity for Hg by quartz-rich windblown sand. Areas with high Hg concentrations are distributed in the eastern and northwestern parts of the study region. Fifteen anomalous Hg enriched areas were delineated in the study region, among which 24 high Hg concentration centers (>25.4 ng/g, > Q85%) reached the scale of geochemical provinces. The high concentration of Hg in these centers is attributed to the widespread distribution of minerals containing elevated concentrations of Hg, minerals that produce substantial quantities of Hg as a by-product, and anthropogenic contributions such as mining and smelting activities. The enrichment of Hg in certain areas is an effective indicator of the occurrence of ore deposits. The Hg geochemical data obtained from the Sino-Mongolian border region is an important reference for further studies on geology, mineral exploration, and environmental protection.

Spatial variations of Rn and CO2 emissions in the Wuzhong–Lingwu region, northwest China

Soil gas Rn and CO2 in surface rupture and deep-seated fault zones are important indicators for tectonic and seismic activities. The spatial distributions of Rn and CO2 concentrations and their relationships with earthquakes and stress state in the Wuzhong–Lingwu area of Ningxia, Northwest China, were investigated through field observations based on 76 measurement points, spatial interpolation and six crossing-fault profiles along Yellow River Fault zone (YRF). Observed results of the soil gas Rn and CO2 in different segments of Yellow River Fault zone illustrated that YRF has features of both strike-slip and certain normal fault characteristics. Moreover, the difference in seismic activity could also account for the differences in gas concentration and relative activity intensity (RAI) in the Yellow River Fault zone. Significant differences in the spatial distributions of Rn and CO2 were identified in gridded observation mode. By comparing these spatial distributions with the surface latent heat flux (SLHF), volumetric soil water layer (SWVL), and lithology, an anomalous high-Rn area was identified in the east and south Qingtongxia, and associated with Permian sandstone and mudstone in a piedmont setting. Away from a strong impact of irrigation in the Yinchuan Basin, CO2 anomalies were identified in the transition area between the Yinchuan Basin and the mountains and coincided with a dramatic negative variation of surface latent heat flux, which was considered to reflect humus accumulation, rich organic matter, and strong soil microorganism activity in loosely accumulated mountain alluvial deposits. After excluding gas anomalies related to shallow soils and surface geology, anomalies of Rn and CO2 in the west of Lingwu were consistent with the distribution of low seismic b-values and frequent seismic activity in plane and profile. According to similar studies in the north-south seismic belts, it is believed that high stress and strong seismic activity increased the permeability of rocks and boosted the gas emission in the west of Lingwu. Base on a crustal thickness variation belt, high-velocity bodies, and in this region, an higher seismic hazard was illustrated. This study offers new insight into combining geochemical characteristics of soil gas and seismological methods to estimate regional seismic hazards.

Applied Methodological Approach for the Assessment of Soil Contamination by Trace Elements around Abandoned Coal Mines—A Case Study of the Jerada Coal Mine, Morocco

Previously conducted studies have established that soil contamination by trace elements (TEs) around coal mines affects ecological biodiversity and human health. One of the ways to protect the health of the surrounding population of coal mine sites is through the assessment of contamination impacts by accurate procedures for the establishment of relevant reclamation plan. The aim of the study is to develop an applied methodological approach to easily assess and quantify the impact of coal mining on the surrounding soils. To achieve this goal, a set of relevant geochemical indexes (enrichment factor—EF, geochemical background—GB, and geoaccumulation index—Igeo) and a geostatistical interpolation for mapping soil contamination were applied. It is experimentally established that the process of combining these techniques can be of great interest in highlighting the anomalous areas and revealing the contamination sources. A case study has been carried out on of the abandoned coal Jerada mine site in Morocco. Soils and coal mine waste rocks (CMWR) samples were collected from this site. Soil and CMWR samples were analyzed for their geochemical content. CMWRs were characterized further for their mineralogical composition and environmental behavior. Based on the EF, three TEs (As, Pb, and Zn) were targeted. The results of GB and Igeo calculations have established an evident relationship between the CMWR dump and the occurred soil contamination. TEs distribution pattern has been revealed using the obtained geochemical maps. The developed methodological approach may be in high demand when assessing soil contamination in most of abandoned coal mine sites around the word.

Differentiation of Wheat Diseases and Pests Based on Hyperspectral Imaging Technology with a Few Specific Bands

Hyperspectral imaging technique is known as a promising non-destructive way for detecting plants diseases and pests. In most previous studies, the utilization of the whole spectrum or a large number of bands as well as the complexity of model structure severely hampers the application of the technique in practice. If a detection system can be established with a few bands and a relatively simple logic, it would be of great significance for application. This study established a method for identifying and discriminating three commonly occurring diseases and pests of wheat, i.e., powdery mildew, yellow rust and aphid with a few specific bands. Through a comprehensive spectral analysis, only three bands at 570, 680 and 750 nm were selected. A novel vegetation index namely Ratio Triangular Vegetation Index (RTVI) was developed for detecting anomalous areas on leaves. Then, the Support Vector Machine (SVM) method was applied to construct the discrimination model based on the spectral ratio analysis. The validating results suggested that the proposed method with only three spectral bands achieved a promising accuracy with the Overall Accuracy (OA) of 83%. With three bands from the hyperspectral imaging data, the three wheat diseases and pests were successfully detected and discriminated. A stepwise strategy including background removal, damage lesions recognition and stresses discrimination was proposed. The present work can provide a basis for the design of low cost and smart instruments for disease and pest detection.

Research on hidden fire source detection in goaf of Hengyi coal mine

Coal fires cause waste of coal resources, air pollution, and threaten the safe production of coal mines, but concealed fire source detection is difficult, and a single detection method has limitations, which makes it difficult to accurately determine the location of fire source. In order to verify the detection effect of the composite detection method on the concealed fire source, according to the isotope radon detection method and magnetic detection principle, the proton magnetometer and radon meter were used to detect the hidden fire source detection area of Hengyi Coal Mine. According to the verification of subsequent anomalous area drilling, the results show that when detecting hidden fire sources, a variety of fire source detection methods can improve the accuracy and efficiency of fire source detection. The exploration and research in Hengyi Coal Mine has laid a solid foundation for the subsequent work of extinguishing coal fires, which is conducive to the safe production of coal mines.