Detecting Underground Mines by Seismic Noise Autocorrelation and Geophysical Methods

2021 ◽  
Author(s):  
Martín Cárdenas-Soto ◽  
Jesús Sánchez-Gónzalez ◽  
José Martínez-González ◽  
Gerardo CIFUENTES-NAVA ◽  
David Zenil
Keyword(s):  
Seismic Noise ◽  
Geophysical Methods ◽  
Underground Mines

Detecting Underground Mines by Seismic Noise Autocorrelation and Geophysical Methods

2021 ◽  
Author(s):  
Martín Cárdenas-Soto ◽  
Jesús Sánchez-Gónzalez ◽  
José Martínez-González ◽  
Gerardo CIFUENTES-NAVA ◽  
David Zenil
Keyword(s):  
Seismic Noise ◽  
Geophysical Methods ◽  
Underground Mines

Destress blasting in deep mines of NorNickel’s Polar Division

2021 ◽  
pp. 32-36
Author(s):  
G. V. Sabyanin ◽  
S. Yu. Shilenko ◽  
A. V. Trofimov ◽  
A. P. Kirkin
Keyword(s):  
Horizontal Plane ◽  
Large Diameter ◽  
Geophysical Methods ◽  
Full Scale ◽  
Underground Mines ◽  
Destress Blasting ◽  
Drilling Cost ◽  
Full Scale Tests ◽  
Polar Division ◽  
Oktyabrsky Mine

Talnakh and Oktyabrsky ore fields are estimated as rockburst-hazardous starting from the depth of 700 m downward according to safety rules. This means that mining is only permitted within certain protected zones. At the present times, such protected zones are generated in underground mines by means of the large-diameter destressing drilling. Despite proved efficiency, the high cost and large amount of the destressing drilling are the grave faults of this approach. Aiming to save drilling cost, it is proposed to make rock mass rockburst-unhazardous using destress blasting. This article gives a brief description of the destress blasting mechanism. This method has been effectively used in relaxation of pillars from stresses before extraction of the reserves from the pillars both in Russia and abroad. In Oktyabrsky Mine stress relaxation of pillars was implemented by slotting, and the drilling and blasting data were available. This study proposes to destress rock masses by means of directional destress fracturing in horizontal plane through blasting of decked charges of special design. The initial parameters for destress blasting using holes with diameters of 76 and 130 mm are determined. The charge design aimed to ensure a zone of fractures in the horizontal plane, at minimized vertical fracturing is described. This information can be used in planning of full-scale tests to refine parameters and application ranges of the method. For the full-scale tests, it is suggested to undertake destress blasting at different blast patterns on different test sites, and to compare the results with the current destressing method (destressing drilling). Efficiency can be proved using geomechanical and geophysical methods. The authors appreciate participation of V. P. Marysyuk and T. P. Darbinyan from NorNickel’s Polar Division in this study.

scholarly journals Seismic noise-based methods for soft-rock landslide characterization

2007 ◽  
Vol 178 (2) ◽  
pp. 137-148 ◽  
Author(s):  
Ombeline Méric ◽  
Stéphane Garambois ◽  
Jean-Philippe Malet ◽  
Héloïse Cadet ◽  
Philippe Guéguen ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Slip Surface ◽  
Geophysical Methods ◽  
Soft Rock ◽  
Hazard Mapping ◽  
S Wave ◽  
Seismic Profiles ◽  
Electrical Tomography ◽  
Slip Surfaces ◽  
Set Up

Abstract In order to better understand the mechanics and dynamic of landslides, it is of primary interest to image correctly their internal structure and their slip surface. Several active geophysical methods are able to provide the geometry of a given landslide, but were rarely applied in 3 dimensions in the past. The main disadvantages of methods like seismic reflection and electrical tomography are that there are heavy to set up and/or to process, and they consequently are expensive and time consuming. Moreover, in the particular case of soft-rock landslides, their respective sensitivity and resolution are not always adequate to locate the potential slip surfaces. Passive methods may represent an interesting alternative particularly for landslides difficult to access, as they require lighter instrumentation and easier processing tools. Among them, the seismic noise based methods have shown increasing applications and developments, in particular for seismic hazard mapping in urban environment. In this paper, we present seismic noise investigations carried out on two different sites, the “Super Sauze” mudslide and the “Saint Guillaume” translational clayey landslide (France), where independent measurements (geotechnical and geophysical tests) were performed earlier. Our investigations were composed of electrical tomography profiles, seismic profiles for surface-wave inversions, H/V measurements, which are fast and easy to perform in the field, in order to image shear wave contrasts (slip surfaces), and seismic noise array method, which is heavier to apply and interpret, but provides (S)-waves velocity profile versus depth. For both sites, landslide bodies are characterized by lower S wave velocity (Vs < 300 m.s−1) and lower resistivity (ρ < 60 Ohm.m) than in the stable part (Vs > 550 m.s−1; ρ > 150 ohm.m). Their thickness vary from a few m to 50 m. Comparison between geophysical investigations and geotechnical data proved the applicability of such passive methods in 3D complex structures, with however some limitations.

Exploring a near‐surface subsidence over a rehabilitated underground mine through ambient seismic noise tomography in combination with other geophysical methods

2020 ◽  
Vol 18 (5) ◽  
pp. 483-495
Author(s):  
Martín Cárdenas‐Soto ◽  
David Escobedo‐Zenil ◽  
Andrés Tejero‐Andrade ◽  
Muricio Nava‐Flores ◽  
Martín Carlos Vidal‐García ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Geophysical Methods ◽  
Underground Mine ◽  
Surface Subsidence ◽  
Ambient Seismic Noise ◽  
Near Surface

Integration of Multi-geophysical Approaches to Identify Potential Pathways of Heavy Metals Contamination - A Case Study in Zeida, Morocco

2020 ◽  
Vol 25 (3) ◽  
pp. 415-423
Author(s):  
Ahmed Lachhab ◽  
El Mehdi Benyassine ◽  
Mohamed Rouai ◽  
Abdelilah Dekayir ◽  
Jean C. Parisot ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Electrical Current ◽  
P Wave ◽  
Low Resistivity ◽  
Refraction Tomography ◽  
Geophysical Surveys

The tailings of Zeida's abandoned mine are found near the city of Midelt, in the middle of the high Moulouya watershed between the Middle and the High Atlas of Morocco. The tailings occupy an area of about 100 ha and are stored either in large mining pit lakes with clay-marl substratum or directly on a heavily fractured granite bedrock. The high contents of lead and arsenic in these tailings have transformed them into sources of pollution that disperse by wind, runoff, and seepage to the aquifer through faults and fractures. In this work, the main goal is to identify the pathways of contaminated water with heavy metals and arsenic to the local aquifers, water ponds, and Moulouya River. For this reason, geophysical surveys including electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and very low-frequency electromagnetic (VLF-EM) methods were carried out over the tailings, and directly on the substratum outside the tailings. The result obtained from combining these methods has shown that pollutants were funneled through fractures, faults, and subsurface paleochannels and contaminated the hydrological system connecting groundwater, ponds, and the river. The ERT profiles have successfully shown the location of fractures, some of which extend throughout the upper formation to depths reaching the granite. The ERT was not successful in identifying fractures directly beneath the tailings due to their low resistivity which inhibits electrical current from propagating deeper. The seismic refraction surveys have provided valuable details on the local geology, and clearly identified the thickness of the tailings and explicitly marked the boundary between the Triassic formation and the granite. It also aided in the identification of paleochannels. The tailings materials were easily identified by both their low resistivity and low P-wave velocity values. Also, both resistivity and seismic velocity values rapidly increased beneath the tailings due to the compaction of the material and lack of moisture and have proven to be effective in identifying the upper limit of the granite. Faults were found to lie along the bottom of paleochannels, which suggest that the locations of these channels were caused by these same faults. The VLF-EM surveys have shown tilt angle anomalies over fractured areas which were also evinced by low resistivity area in ERT profiles. Finally, this study showed that the three geophysical methods were complementary and in good agreement in revealing the pathways of contamination from the tailings to the local aquifer, nearby ponds and Moulouya River.

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