Seismic attenuation spectra in rock mass characterization; a case study in open‐pit mining

Geophysics ◽  
1986 ◽  
Vol 51 (2) ◽  
pp. 302-323 ◽  
Author(s):  
R. P. Young ◽  
J. J. Hill
Keyword(s):  
Rock Mass ◽  
Three Dimensional ◽  
Seismic Attenuation ◽  
Phase Iii ◽  
Open Pit ◽  
Open Pit Mining ◽  
Rock Masses ◽  
Rock Mass Characterization ◽  
Fracture Anisotropy

The application of engineering geophysics to the characterization of rock masses is exemplified through a case study of three phases of a research project into the design of efficient blasting systems in open‐pit mining. Seismic experiments are used before and after mine blasting to monitor the efficiency of explosions in terms of rock fragmentation. Spectral analysis of seismic signals, after they have been used to interrogate rock masses, is used to compute preblast and postblast attenuation and velocity parameters. The results show that fragmentation efficiency of a mine blast and fracture anisotropy of a rock mass can be quantified in terms of three‐dimensional (3-D) attenuation spectra and polar anisotropy diagrams. These seismic data are correlated with the blast design and the energy used by the excavating dragline machine to dig to rock mass. An overview of the seismic attenuation technique and instrumentation used in the project (phases I and II) is given. A case study from phase III highlights the scope and interpretation of the relationship between excavation parameters and seismically characterized blasting efficiency.

scholarly journals Study on the influence of the deformation zones of the quarry sides on the rock mass movement

2021 ◽  
Vol 304 ◽  
pp. 02002
Author(s):  
Vokhid Kadirov ◽  
Sherzod Karimov ◽  
Uchqun Qushshayev ◽  
Durdona Sharapova
Keyword(s):  
Rock Mass ◽  
Mass Movement ◽  
Physical And Mechanical Properties ◽  
Structural Features ◽  
Open Pit ◽  
Open Pit Mining ◽  
Rock Masses ◽  
Mining Operations ◽  
Dump Trucks ◽  
The Stability

The article presents a study and analysis of the causes of deformation of the slopes and sides of the quarry indicates that the magnitude and nature of the deformation processes depend on the height of the ledge, the angle of slope of the slopes, the physical and mechanical properties, the lithological and structural features of the instrument array and the geodynamic activity of the fault zones. The influence of the deformation zones of the sides of the quarry on the transport of rock masses is justified. The zone of deformed masses of the ore deposit, which affect the movement of the rock mass, is studied. Each process performed in open pit mining is linked to another workflow. Without ensuring the safety of mining operations and performing the tasks set is impossible. Transportation of rock masses in the lower horizons of a deep quarry is one of the main tasks of the industry. At the same time, the removal of deformation and landslides in the area where the transport berm is being constructed for draining and continuous transportation is the main goal of the quarry. The stability of the transport berm depends directly on the stability of the side of the quarry. It is determined that the choice of a single-lane or twolane transport berm constructed for heavy-duty quarry dump trucks depends on the condition of the side of the quarry.

Case study: open pit three-dimensional slope stability back-analysis for an anisotropic iron ore rock mass

2021 ◽  
Author(s):  
Lucas Figueiredo ◽  
Manollo Barros ◽  
Reginald Hammah ◽  
Yan Santos ◽  
Thaisa Souza ◽  
...  
Keyword(s):  
Rock Mass ◽  
Slope Stability ◽  
Iron Ore ◽  
Three Dimensional ◽  
Back Analysis ◽  
Open Pit

General concept of determining the parameters of non-mining walls of ultra-deep diamond deposits development open pits

2021 ◽  
pp. 48-53
Author(s):  
I. V. Zyryanov ◽  
A. N. Akishev ◽  
I. B. Bokiy ◽  
N. M. Sherstyuk
Keyword(s):  
Rock Mass ◽  
Structural Relaxation ◽  
Slope Angle ◽  
Field Tests ◽  
Friction Angle ◽  
Strength Properties ◽  
Strength Characteristics ◽  
Open Pit ◽  
Open Pit Mining ◽  
Relaxation Coefficient

A specific feature of open pit mining of diamond deposits in Western Yakutia is the construction of the open pits in the zone of negative ambient temperatures, which includes thick permafrost rock mass, and which is at the same time complicated by the influence of cryogenic processes on deformation of pit wall benches. The paper presents the comparative analysis of strength characteristics in frozen and thawed rocks, stability of benches during mining, the general geomechanical approach to the determination of parameters of non-mining walls of the ultra-deep open pit diamond mines, and the parameters of nonmining walls and benches. Optimization of open pit wall configuration should primarily be based on the maximum utilization of the strength properties of frozen rocks in combination with the development of new approaches, calculation schemes and methods for assessing stability of open pit walls and benches of unconventional design, including the non-mining vertical benches. The main design characteristic that determines the parameters of open pit walls is the structural tectonic relaxation coefficient, which specifies the calculated value of cohesion in rock mass. For the diamond deposits, the values of the structural relaxation coefficient were obtained in a series of field tests and back calculations. Full-scale tests were carried out both during exploration operations in underground mines and in open pits. The accuracy of determining the values of the structural relaxation coefficient in the range of 0.085–0.11 is confirmed by the parameters of non-mining walls in an open pit mine 385–640 m deep, with overall slope angles of 38–55° and a steeper H 0.35–0.5 lower part having the slope angle of up to 70° with average strength characteristics of 7.85–11.84 MPa and the internal friction angle of 28.1–37.4°. Using the natural load-bearing capacity of rock mass to the full advantage, which the values of the structural relaxation coefficient of deposits show, allows optimization of open pit wall slope design and minimization of stripping operations.

Implementation of InfraRed Thermographic surveys in complex coastal areas: the case study of Polignano a Mare (southern Italy)

2021 ◽  
Author(s):  
Lidia Loiotine ◽  
Marco La Salandra ◽  
Gioacchino Francesco Andriani ◽  
Eliana Apicella ◽  
Michel Jaboyedoff ◽  
...  
Keyword(s):  
Rock Mass ◽  
Structure From Motion ◽  
Southern Italy ◽  
Thermal Imager ◽  
Rock Masses ◽  
Field Surveys ◽  
Thermal Images ◽  
Thermal Anomalies ◽  
Rock Face

<p><em>InfraRed Thermography</em> (IRT) spread quickly during the second half of the 20<sup>th</sup> century in the military, industrial and medical fields. This technique is at present widely used in the building sector to detect structural defects and energy losses. Being a non-destructive diagnostic technique, IRT was also introduced in the Earth Sciences, especially in the volcanology and environmental fields, yet its application for geostructural surveys is of recent development. Indeed, the acquisition of thermal images on rock masses could be an efficient tool for identifying fractures and voids, thus detecting signs of potential failures.<br>Further tests of thermal cameras on rock masses could help to evaluate the applicability, advantages and limits of the IRT technology for characterizing rock masses in different geological settings.<br>We present some results of IRT surveys carried out in the coastal area of Polignano a Mare (southern Italy), and their correlation with other remote sensing techniques (i.e. <em>Terrestrial Laser Scanning</em> and <em>Structure from Motion</em>). The case study (<em>Lama Monachile</em>) is represented by a 20 m-high cliff made up of Plio-Pleistocene calcarenites overlying Cretaceous limestones. Conjugate fracture systems, karst features, folds and faults, were detected in the rock mass during field surveys. In addition, dense vegetation and anthropogenic elements, which at places modified the natural setting of the rock mass, represent relevant disturbances for the characterization of the rock mass. In this context, IRT surveys were added to the other techniques, aimed at detecting the major discontinuities and fractured zones, based on potential thermal anomalies. <br>IRT surveys were carried out in December 2020 on the east side of the rock mass at <em>Lama Monachile</em> site. Thermal images were acquired every 20 minutes for 24 hours by means of a FLIR T-660 thermal imager mounted on a fixed tripod. Ambient air temperature and relative humidity were measured during the acquisition with a pocketsize thermo-hydrometer. A reflective paper was placed at the base of the cliff to measure the reflected apparent temperature. In addition, three thermocouple sensors were fixed to the different lithologic units of the rock face. These parameters, together with the distance between the FLIR T-660 and the rock face, were used in order to calibrate the thermal imager and correct the apparent temperatures recorded by the device, during the post-processing phase. Successively, vertical profiles showing the temperature of the rock face over time were extracted from the thermograms. Thermal anomalies were correlated with stratigraphic and Geological Strength Index profiles, obtained by means of field surveys and Structure from Motion techniques. The presence of fracture and voids in the rock mass was also investigated.</p>

ENVIRONMENTAL ISSUES OF SURFICIAL URANIUM DEPOSITS: OUM DHEROUA CASE STUDY (ISLAMIC REPUBLIC MAURITANIA)

2021 ◽  
Author(s):  
Mariia Kurylo ◽  
Ivan Virshylo
Keyword(s):  
Clean Energy ◽  
Raw Material ◽  
Open Pit ◽  
Open Pit Mining ◽  
Material Base ◽  
Uranium Deposits ◽  
Islamic Republic ◽  
Natural Ecosystems ◽  
Lower Estimation

Uranium deposits and resources are considered as an important raw material base for the implementation of scenarios for the green and clean energy transition. Traditionally discussed risks of potential environmental impacts of Uranium projects development could be subdivided by deposit type. Surficial type mineralization connected to the calcretes in shallow paleovalleys or playas has many specific features which might be analysed separately. Case study of Oum Dheroua Uranium project in the Islamic Republic of Mauritania shows an unexpected lower estimation of environmental risks comparatively to conventional Uranium projects despite to open-pit mining technology. The reasons for such estimation, connected to geographic location, the inclusion of Uranium minerals in natural ecosystems and low scale of deposits (both in grade and size sense). Potential by-products (Vanadium and Strontium) are not part of environmental factors assessment.

scholarly journals Brown Coal in Victoria, Australia and Maddingley Brown Coal Open Cut Mine Batter Stability

2020 ◽  
Vol 9 (3) ◽  
pp. 109-118
Author(s):  
Lei Zhao ◽  
Greg You
Keyword(s):  
Coal Seam ◽  
Brown Coal ◽  
Large Scale ◽  
Low Cost ◽  
Three Dimensional ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Operations ◽  
Power Generators ◽  
Three Dimensional Finite Element

Brown coal is young, shallowly deposited, and widely distributed in the world. It is a fuel commonly used to generate electricity. This paper first reviews the resources and characteristics of brown coal in Victoria, Australia, and its exploitation and contribution to the economy or power supply in Victoria. Due to the shallow depth of the brown coal seam, e.g. very favorable stripping ratio, open pit mining is the only mining method used to extract the coal at low cost for power generators. With the large-scale mining operations, cases of batter failure were not rare in the area. From the comprehensive review of past failures, overburden batter tends to fail by circular sliding, coal batter tends to fail by block sliding after the overburden is stripped due to a weak water-bearing layer underneath the coal seam and tension cracks developed at the rear of the batter, and batter failure is typically coincided with peak raining seasons. Secondly, the paper reviews the case study of Maddingley Brown Coal (MBC) Open Cut Mine batter stability, including geology, hydrogeology, and hydro-mechanically coupled numerical modelling. The modelling employs three-dimensional finite element method to simulate the MBC northern batter where cracks were observed in November 2013. The comprehensive simulation covers an overburden batter, a brown coal batter, two rainfall models, and a buttressed batter. The simulated results agree well with observed data, and it is found that the rainfall at the intensity of 21mm substantially lowered the factor of safety of the coal batter.

Stochastic Three-Dimensional Joint Geometry Model and the Properties of REV for a Jointed Rock Mass

2014 ◽  
Vol 1079-1080 ◽  
pp. 266-271
Author(s):  
Wen Hui Tan ◽  
Zhong Hua Sun ◽  
Ning Li ◽  
Xiao Hong Jiang
Keyword(s):  
Rock Mass ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Open Pit ◽  
Mechanical Parameters ◽  
Geometry Model ◽  
Joint Geometry ◽  
3D Network

The lithology of rock mass isnon-homogeneity，anisotropy, andexists size effect. The mechanical parameters of rock mass gotten by engineeringapproaches cannot reflect these properties. Therefore, a newmethod of determining the mechanical parameters of jointed rock mass isproposed: gneiss in Shuichang open-pit mine was selected as a case, thefracture system of the rock mass was measured and analyzed by non-contactmeasuring system of 3GSM and probabilisticmethod,the probability distributions of geometry parameters were analyzed and a 3Djoint geometry model was made by using the program of 3D network modeling.Cubes with different sizes were selected to be tested by tri-axial compressionof numerical simulation with 3DEC based on the 3D network model of joints,thus, the REV and its mechanical parameters were determined, which providedcredible parameters for slope stability analysis.

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