Metalliferous mining geophysics—State of the art in the last decade of the 20th century and the beginning of the new millennium

Geophysics ◽  
2002 ◽  
Vol 67 (3) ◽  
pp. 964-978 ◽  
Author(s):  
Misac N. Nabighian ◽  
Michael W. Asten
Keyword(s):  
Time Domain ◽  
Wavelet Transforms ◽  
Gamma Ray ◽  
Mining Industry ◽  
Principal Component ◽  
Mine Planning ◽  
Oil Field ◽  
Airborne Gravity ◽  
Gravity Gradient ◽  
Technological Developments

The downturn in mining activity experienced during the 1990s did not preclude significant new developments in various areas of mining geophysics. The methodology for acquiring and compiling data has kept pace with the latest technological developments, from Global Positioning System navigation to raster displays and parallel computing. Wavelet transforms, principal component analysis, and fractals have begun to find successful applications in both processing and interpretation of geophysical data. Methods of quantitatively interpreting/inverting anomalies in terms of 2‐D and 3‐D models of causative bodies are becoming common. For the first time it is possible to make airborne gravity gradient measurements suitable for use in mineral exploration. Lower transmitter frequencies for airborne time‐domain electromagnetic (EM) systems have enabled surveys in areas where conductive cover previously screened basement conductors. The use of approximation algorithms has allowed the transformation of either time‐domain or frequency‐domain data into conductivity‐depth images (CDIs) which expedite interpretation. Full‐waveform recording and the use of multiple receivers are becoming common for ground EM techniques. In radiometrics it is now common practice to record 256 channels of spectral data which, by using statistical methods, has led to a dramatic reduction of noise in aerial gamma‐ray surveys. Finally, advances in 3‐D oil‐field seismic reflection methods have been introduced into the search for mineral deposits, thereby providing new tools for studying the environment of orebody emplacement as well as detailed geometrical information of value for both exploration and mine‐planning applications. Thus, at the beginning of the 21st century, we find the geophysical techniques used by the mining industry to be at the forefront of the latest technological developments.

Next Generation High Resolution Airborne Gravity Reconnaissance in Oil Field Exploration

1993 ◽  
Vol 11 (3-4) ◽  
pp. 198-234 ◽  
Author(s):  
J.M. Bodard ◽  
J.G. Creer ◽  
M.W. Asten
Keyword(s):  
Gravity Field ◽  
Oil Field ◽  
Petroleum Exploration ◽  
Airborne Gravity ◽  
Gravity Gradient ◽  
Practical Implementation ◽  
Gravity Gradients ◽  
Gravity Gradiometry ◽  
Near Surface ◽  
Migration Pathways

Simple modelling studies of gravity fields using elementary structural forms, oilfield-type structures and geological reconnaissance situations, show that gravity gradiometry technology offers significant petroleum exploration potential. In geological environments of interest, gravity gradients are primarily due to density displacement along (near) vertical boundaries. Gradient images therefore reveal the edges and corners of intrusions, faults, fault intersections, and other such structures often associated with hydrocarbon migration pathways and traps, and/or significant basinal trends. Recent technological advances may make gravity gradiometry an airborne reconnaissance tool capable of providing sensitivity and resolution superior to the best gravimetry available today. This capacity, and the array of gradient components that may be measured, will embellish aspects of the gravity field important to developing regional geologic interpretations. While the potential advantage of gravity gradiometry is greater lateral resolution and sensitivity from a moving platform, the disadvantage is the high sensitivity to topographic and shallow buried irregularities unrelated to the deeper geological structures of interest. A further difficulty is the complex gravity field representations produced for density structures of certain geometries. Buried features that have near surface expressions will be easiest to map. However, full use of gravity gradient technology will require application-focused data processing techniques and new interpretation skills. When the technology becomes commercially available it could find application in preseismic reconnaissance, structural (and possibly stratigraphic) mapping, acreage management and assessment, and in the evolution and mapping of controls on oilfield distribution. The technology could help develop exploration in remote and inaccessible areas, and provide a new look at well-explored regions. An immediate practical implementation appears to be in offshore exploration applications, possibly linked to deepwater exploitation strategies.

scholarly journals Multivariate Geostatistical Modeling of Lower Calorific Value in Multi-Seam Coal Deposits

2020 ◽  
Vol 10 (18) ◽  
pp. 6208
Author(s):  
Daphne Sideri ◽  
Christos Roumpos ◽  
Francis Pavloudakis ◽  
Nikolaos Paraskevis ◽  
Konstantinos Modis
Keyword(s):  
Power Plants ◽  
Mining Industry ◽  
Principal Component ◽  
Calorific Value ◽  
Mine Planning ◽  
Borehole Data ◽  
Multivariate Geostatistics ◽  
Quality Properties ◽  
Research Outcomes ◽  
Coal Deposits

The estimation of fuel characteristics and spatial variability in multi-seam coal deposits is of great significance for the optimal mine planning and exploitation, as well as for the optimization of the corresponding power plants operation. It is mainly based on the quality properties of the coal (i.e., Lower Calorific Value (LCV), ash content, CO2, and moisture). Even though critical, these properties are not always measured in practice for all available borehole samples, or, they are generally estimated by using non-parametric statistics. Therefore, spatial modeling of LCV can become problematic due to the limited number of data. Thus, the use of other available correlated attributes might be helpful. In this research, techniques of multivariate geostatistics were used to estimate and evaluate the spatial distribution of quality properties in a multi-seam coal deposit, with special reference to the LCV. More specifically, kriging, cokriging, and Principal Component Analysis (PCA) techniques were tested in a case study as estimators of the LCV, using an extensive set of borehole data from the South Field lignite mine in Ptolemais, Greece. The research outcomes show that the application of kriging with two PCA factors and the use of inverse transform result in the best LCV estimates. Moreover, cokriging with two auxiliary variables gives more accurate values for a LCV estimate, in relation to the kriging technique. The research outcomes could be considered significant for the coal mining industry, since the use of correlated quality attributes for the estimation of LCV may contribute to a reduction of the estimation uncertainty at no additional drilling cost.

scholarly journals Lightweight Unmanned Aerial System for Time-Domain Electromagnetic Prospecting—The Next Stage in Applied UAV-Geophysics

2021 ◽  
Vol 11 (5) ◽  
pp. 2060 ◽  
Author(s):  
Alexander Parshin ◽  
Ayur Bashkeev ◽  
Yuriy Davidenko ◽  
Marina Persova ◽  
Sergey Iakovlev ◽  
...  
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
Pulse Generator ◽  
Measuring System ◽  
Electromagnetic Sounding ◽  
Mountainous Regions ◽  
Time Domain Electromagnetic ◽  
Unmanned System ◽  
Classical Triad ◽  
The Time Domain

Nowadays in solving geological problems, the technologies of UAV-geophysics, primarily magnetic and gamma surveys, are being increasingly used. However, for the formation of the classical triad of airborne geophysics methods in the UAV version, there was not enough technology for UAV-electromagnetic sounding, which would allow studying the geological environment at depths of tens and hundreds of meters with high detail. This article describes apparently the first technology of UAV-electromagnetic sounding in the time domain (TDEM, TEM), implemented as an unmanned system based on a light multi-rotor UAV. A measuring system with an inductive sensor—an analogue of a 20 × 20 or 50 × 50 m receiving loop is towed by a UAV, and a galvanically grounded power transmitter is on the ground and connected to a pulse generator. The survey is carried out along a network of parallel lines at low altitude with a terrain draping at a speed of 7–8 m/s, the maximum distance of the UAV’s departure from the transmitter line can reach several kilometers, thus the created technology is optimal for performing detailed areal electromagnetic soundings in areas of several square kilometers. The results of the use of the unmanned system (UAS) in real conditions of the mountainous regions of Eastern Siberia are presented. Based on the obtained data, the sensitivity of the system was simulated and it was shown that the developed technology allows one to collect informative data and create geophysical sections and maps of electrical resistivity in various geological situations. According to the authors, the emergence of UAV-TEM systems in the near future will significantly affect the practice of geophysical work, as it was earlier with UAV-magnetic prospecting and gamma-ray survey.

scholarly journals Non-Adaptive Methods for Fetal ECG Signal Processing: A Review and Appraisal

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3648 ◽  
Author(s):  
Rene Jaros ◽  
Radek Martinek ◽  
Radana Kahankova
Keyword(s):  
Signal Processing ◽  
Wavelet Transforms ◽  
Principal Component ◽  
Fetal Monitoring ◽  
Adaptive Methods ◽  
Component Analysis ◽  
Adaptive Signal Processing ◽  
Extensive Literature ◽  
Fetal Electrocardiogram ◽  
Fetal Ecg

Fetal electrocardiography is among the most promising methods of modern electronic fetal monitoring. However, before they can be fully deployed in the clinical practice as a gold standard, the challenges associated with the signal quality must be solved. During the last two decades, a great amount of articles dealing with improving the quality of the fetal electrocardiogram signal acquired from the abdominal recordings have been introduced. This article aims to present an extensive literature survey of different non-adaptive signal processing methods applied for fetal electrocardiogram extraction and enhancement. It is limiting that a different non-adaptive method works well for each type of signal, but independent component analysis, principal component analysis and wavelet transforms are the most commonly published methods of signal processing and have good accuracy and speed of algorithms.

scholarly journals ROLE OF THE 3.6M DOT TO INVESTIGATE CONNECTIONS BETWEEN LONG-GRBS AND CORE-COLLAPSE SNE

2021 ◽  
Vol 53 ◽  
pp. 127-133
Author(s):  
A. Kumar ◽  
S. B. Pandey ◽  
R. Gupta ◽  
A. Aryan ◽  
A. J. Castro-Tirado ◽  
...  
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Global Network ◽  
Core Collapse ◽  
Robotic Telescopes ◽  
The Time Domain ◽  
Time Critical ◽  
Near Future

Newly installed 3.6m DOT at Nainital (Uttarakhand) is a novel facility for the time domain astronomy. Because of the longitudinal advantage of India, it could be used to study new transients reported by a global network of robotic telescopes. Observations with the 4K × 4K CCD Imager at the axial port of the 3.6m DOT will be very helpful in the near future towards understanding the different physical aspects of time-critical events, e.g., Gamma-ray bursts (GRBs), Supernovae, Gravitational wave candidates, etc. Using the Imager with broadband filters (Bessel UBVRI and SDSS ugriz), ~6.5' × 6.5' images could be obtained to attempt various science goals in synergy with other multi-band facilities. In this study, we present an analysis of unpublished R-band data of GRB 171205A/SN 2017iuk spanning between ~12 to 105 days since burst, that observed using the 3.6m DOT with 4K × 4K CCD Imager. In the R-band light curve, a bump appears to start from ~3 days, which shows the peak at ~15 days after the burst, clearly indicates photometric evidence of association of SN with GRB 171205A.

scholarly journals Petrophysical Properties and Digenetic Evolution of Shuaiba Formation in Nasiriyah Oil Field, Southern Iraq

2021 ◽  
pp. 4810-4818
Author(s):  
Marwah H. Khudhair
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Middle Part ◽  
Effective Porosity ◽  
Oil Field ◽  
Neutron Density ◽  
Petrophysical Properties ◽  
Secondary Porosity ◽  
Primary Porosity ◽  
Gamma Ray Log

     Shuaiba Formation is a carbonate succession deposited within Aptian Sequences. This research deals with the petrophysical and reservoir characterizations characteristics of the interval of interest in five wells of the Nasiriyah oil field. The petrophysical properties were determined by using different types of well logs, such as electric logs (LLS, LLD, MFSL), porosity logs (neutron, density, sonic), as well as gamma ray log. The studied sequence was mostly affected by dolomitization, which changed the lithology of the formation to dolostone and enhanced the secondary porosity that replaced the primary porosity. Depending on gamma ray log response and the shale volume, the formation is classified into three zones. These zones are A, B, and C, each can be split into three rock intervals in respect to the bulk porosity measurements. The resulted porosity intervals are: (I) High to medium effective porosity, (II) High to medium inactive porosity, and (III) Low or non-porosity intervals. In relevance to porosity, resistivity, and water saturation points of view, there are two main reservoir horizon intervals within Shuaiba Formation. Both horizons appear in the middle part of the formation, being located within the wells Ns-1, 2, and 3. These intervals are attributed to high to medium effective porosity, low shale content, and high values of the deep resistivity logs. The second horizon appears clearly in Ns-2 well only.

scholarly journals EXPLORING THE TRANSIENT SKY WITH THE FLY'S EYE CAMERA SYSTEM

2019 ◽  
Vol 51 ◽  
pp. 116-123
Author(s):  
L. Mészáros ◽  
A. Pál ◽  
G. Csépány ◽  
K. Vida ◽  
L. Kriskovics ◽  
...  
Keyword(s):  
Time Domain ◽  
Degrees Of Freedom ◽  
Gamma Ray ◽  
Parallel Robots ◽  
Camera System ◽  
Transient Event ◽  
Astrophysical Objects ◽  
Robotic Telescopes ◽  
Fast Transients ◽  
6 Degrees Of Freedom

To study astrophysical transit phenomena we follow an alternative strategy for getting high-cadence observations of the field. This can be achieved with our new Fly’s Eye Camera System that monitors the entire sky above 30◦ horizontal altitude. With this instrument one can observe all phenomena brighter than ∼ 15m in Sloan r-band (u’, g’,i’ and z’ filters are also available). If we stack together a few hour of images we canobserve ∼ 17 m faint sources. This small-sized instrument is designed for time-domain astronomy with its 150 sec cadence. Due to the hexapod-based motion control, the instrument can be installed anywhere without any modifications, it can accomplish sky tracking automatically. These parallel robots have 6 degrees of freedom (DoF), but since any kind of rotation can be done by using only 3 DoF, the tracking with hexapods is independent from the geographical coordinates. Even polar alignment is not required, because Fly’s Eye can calibrate itself based on its own observed data. The system is optimal for time-domain astronomy: detecting novae, supernovae, optical afterglows of gamma-ray bursts and other bright, fast transients, and, from the observation database such data can be obtained - even from before the discovery of the transient event. In the future when the direction of the gravitational waves will be defined precisely we will be able to detect their first multiwaveband counterparts. In addition the Fly’s Eye will support the “Transient Astrophysical Objects” project which will use two new 80 cm robotic telescopes for follow-up observations of transients.

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