scholarly journals Application of a Wide-Field Electromagnetic Method for Hot Dry Rock Exploration: A Case Study in the Gonghe Basin, Qinghai, China

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1105
Author(s):  
Hui Tan ◽  
Fan Ling ◽  
Zhenwei Guo ◽  
Jie Li ◽  
Jiawei Liu

Hot dry rock (HDR) is a geothermal resource with a high temperature that is widely distributed and has good potential as a clean and renewable energy source. To determine underground electrical structures and to predict granite reservoir distributions, the wide-field electromagnetic (WFEM) method has been applied to explore deep mineral resources and has advantages such as explorations at greater depths and at high resolutions. In this study, a WFEM investigation was carried out for HDR exploration in Gonghe Basin within Qinghai Province. Six parallel survey lines, each spaced apart by 1 km, were designed for WFEM data acquisition. After data processing and inversion, we mapped the subsurface resistivity distribution and divided the inversion resistivity of HDR in the Qiabuqia area into four layers. From the WFEM results, we inferred the location of HDRs, which was verified using drilling wells. HDRs were found at a depth between 3200 m and 3705 m in the well. Furthermore, with the calibration of drilling well GR1, we provided the relationship between temperature and inversion resistivity. From this relationship, the exploration areas with mining potential can be determined.

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 726 ◽  
Author(s):  
Zhenwei Guo ◽  
Longyun Hu ◽  
Chunming Liu ◽  
Chuanghua Cao ◽  
Jianxin Liu ◽  
...  

The electromagnetic (EM) method is commonly used in mineral exploration due to the method’s sensitivity to conductive targets. Controlled source audio-frequency magnetotellurics (CSAMT) is developed from magnetotelluric (MT) method with an artificial EM source to improve the signal amplitude. It has been used for mineral exploration for many years. In this study, we performed a case study of the CSAMT application for the Eagles-Nest lead–zinc (Pb–Zn) ore deposits in Jianshui, China. The Eagles-Nest deposit is located in southwest in China in forest-covered complex terrain, making it difficult to acquire the geophysical data. Based on the previous dual-frequency induced polarization (IP) results, we designed four profiles for the CSAMT data acquisition. After data processing and inversion, we mapped the subsurface resistivity distribution. From the CSAMT results, we inferred the location of the ore body, which was verified by the drilling wells. The Pb–Zn ore body was found at a depth between 373.70 m to 407.35 m in the well.


Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. B133-B140 ◽  
Author(s):  
V. Ramesh Babu ◽  
Subhash Ram ◽  
N. Sundararajan

We present modeling of magnetic and very low frequency electromagnetic (VLF-EM) data to map the spatial distribution of basement fractures where uranium is reported in Sambalpur granitoids in the Raigarh district, Chhattisgarh, India. Radioactivity in the basement fractures is attributed to brannerite, [Formula: see text] complex, and uranium adsorbed on ferruginous matter. The amplitude of the 3D analytical signal of the observed magnetic data indicates the trend of fracture zones. Further, the application of Euler 3D deconvolution to magnetic data provides the spatial locations and depth of the source. Fraser-filtered VLF-EM data and current density pseudosections indicate the presence of shallow and deep conductive zones along the fractures. Modeling of VLF-EM data yields the subsurface resistivity distribution of the order of less than 100 ohm-m of the fractures. The interpreted results of both magnetic and VLF-EM data agree well with the geologic section obtained from drilling.


Author(s):  
Kristina Dietz

The article explores the political effects of popular consultations as a means of direct democracy in struggles over mining. Building on concepts from participatory and materialist democracy theory, it shows the transformative potentials of processes of direct democracy towards democratization and emancipation under, and beyond, capitalist and liberal democratic conditions. Empirically the analysis is based on a case study on the protests against the La Colosa gold mining project in Colombia. The analysis reveals that although processes of direct democracy in conflicts over mining cannot transform existing class inequalities and social power relations fundamentally, they can nevertheless alter elements thereof. These are for example the relationship between local and national governments, changes of the political agenda of mining and the opening of new spaces for political participation, where previously there were none. It is here where it’s emancipatory potential can be found.


2019 ◽  
Vol 16 (3) ◽  
pp. 417-428
Author(s):  
Özgün Ünver ◽  
Ides Nicaise

This article tackles the relationship between Turkish-Belgian families with the Flemish society, within the specific context of their experiences with early childhood education and care (ECEC) system in Flanders. Our findings are based on a focus group with mothers in the town of Beringen. The intercultural dimension of the relationships between these families and ECEC services is discussed using the Interactive Acculturation Model (IAM). The acculturation patterns are discussed under three main headlines: language acquisition, social interaction and maternal employment. Within the context of IAM, our findings point to some degree of separationism of Turkish-Belgian families, while they perceive the Flemish majority to have an assimilationist attitude. This combination suggests a conflictual type of interaction. However, both parties also display some traits of integrationism, which points to the domain-specificity of interactive acculturation.


2019 ◽  
Vol 2 (4) ◽  
pp. 276-291
Author(s):  
Chatarina Natalia Putri

There are many factors that can lead to internship satisfaction. Working environment is one of the factors that will result to such outcome. However, many organizations discarded the fact of its importance. The purpose of this study is to determine whether there is a significant relationship between working environment and internship satisfaction level as well as to determine whether the dimensions of working environment significantly affect internship satisfaction. The said dimensions are, learning opportunities, supervisory support, career development opportunities, co-workers support, organization satisfaction, working hours and esteem needs. A total of 111 questionnaires were distributed to the respondents and were processed by SPSS program to obtain the result of this study. The results reveal that learning opportunities, career development opportunities, organization satisfaction and esteem needs are factors that contribute to internship satisfaction level. In the other hand, supervisory support, co-workers support and working hours are factors that lead to internship dissatisfaction. The result also shows that organization satisfaction is the strongest factor that affects internship satisfaction while co-workers support is the weakest.


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