Geophysical and image processing methods for detection of fireholes in brown coal, Latrobe Valley

1989 ◽  
Vol 20 (2) ◽  
pp. 153
Author(s):  
G.R. Pettifer ◽  
N. Djordjevic ◽  
D. Heislers ◽  
J. Schaeffer ◽  
J.A. Withers
Keyword(s):  
Image Processing ◽  
High Resolution ◽  
Brown Coal ◽  
Geophysical Methods ◽  
Processing System ◽  
Data Sets ◽  
Overburden Thickness ◽  
Thickness Variations ◽  
Coal Reserves ◽  
Low Amplitude

Fireholes at the top of the thick Latrobe Valley brown coal seams pose a geotechnical hazard to overburden dredges and reduce coal reserves. Overburden thickness (typically 10 to 15 m) is up to 50 m in the fireholes, which are from 20 to hundreds of metres in diameter and are infilled with baked clays, soft lacustrine clays and alluvial deposits.Given the complexity of firehole geometry and overburden geology, firehole definition prior to overburden stripping, by drilling alone, is expensive and is not definitive. To improve firehole exploration, geophysical methods were tried in a test area with good borehole control (115 holes), near Morwell open cut.Grid geophysics (20m. � 20m., 2805 grid stations) using gravity, EM34 20 m loop conductivity and high resolution magnetics gave very good results. Shallow seismic reflection methods were not successful.Residual gravity defined overburden thickness variations best with gravity highs of up to 6.5 micrometres/sec2 over the fireholes. EM conductivity showed reasonable correlation with overburden thickness, with EM conductivity highs over fireholes infilled with lower resistivity lacustrine clays and silts. High resolution magnetics using a TM-3 caesium vapour magnetometer, despite high cultural interference, showed broad, low amplitude highs over fireholes where higher susceptibility baked clays are thickest. The three geophysical data sets and overburden data were gridded (5m. � 5m.) and the grids dumped to a MicroBrian image processing system. Conventional image processing analysis was carried out to compare, enhance, filter, display and classify the complementary data sets. A classification scheme for overburden type based on geophysical responses plus a routine firehole exploration methodology using residual gravity, EM, magnetics, progressive drilling data and the image processor was devised to reduce drilling costs and increase exploration confidence. The case history presents the results of the grid geophysics and image processing approach.

Video Image Presentation Methods for High-Speed Mail Piece Encoding

1988 ◽  
Vol 32 (19) ◽  
pp. 1419-1423
Author(s):  
Christopher G. Koch ◽  
Ginny Ju
Keyword(s):  
Image Processing ◽  
High Resolution ◽  
High Speed ◽  
Data Entry ◽  
Processing System ◽  
Response Speed ◽  
Video Images ◽  
Pacing Strategies ◽  
Design Requirements ◽  
Presentation Methods

A program of research was conducted to determine the design requirements for a prototype image processing system to provide high-resolution video images of mail pieces—irregular parcels and pieces, flats, and letters—and enable highspeed data entry of coding information by operators. Experiments were performed to determine effective image transition methods, pacing strategies, and image preview methods for entering numerals from ZIP Codes of mail piece addresses on a 10-key keyboard. Results showed performance advantages of response speed, throughput, and fewer misses for fade-out transition between images, combined operator and machine pacing, and image preview by early transition to the next image in queue.

Digital image processing of airborne geophysical data for uranium‐mineralized breccia pipes exploration in northwestern Arizona

Geophysics ◽  
1990 ◽  
Vol 55 (8) ◽  
pp. 965-976 ◽  
Author(s):  
A. Y. Kwarteng ◽  
P. S. Chavez
Keyword(s):  
Image Processing ◽  
Digital Image Processing ◽  
Digital Image ◽  
Apparent Resistivity ◽  
Low Frequency ◽  
Noise Removal ◽  
Geophysical Data ◽  
Data Sets ◽  
Overburden Thickness ◽  
Airborne Geophysical Data

Digital image processing and integration of data sets have been used to develop exploration models from airborne electromagnetics (EM), magnetics, and very‐low‐frequency electromagnetics (VLF-EM) data collected over an area in northwestern Arizona. The area has potential for the occurrence of uranium‐mineralized breccia pipes. Apparent resistivity and overburden thickness were derived from the EM measurements using half‐space models. Digital image processing techniques applied to the geophysical data sets included: (1) conversion of the data into gridded‐scale images, (2) spatial filtering for noise removal, (3) integration and analysis of the data sets, and (4) modeling using various parameter combinations. The general relationships between the geophysical variables/parameters and their ability to detect metallic deposits were used as guides in selecting digital number ranges that were used as input into various models. One of the best models incorporated apparent resistivity and total‐field magnetics; the results of this model outlined 13 anomalous combinations in the survey area. Field checking confirmed that two of the anomalies were previously known orebodies, and most of the other anomalies corresponded to suspected pipes that were under evaluation by the group that is exploring the property.

scholarly journals Merge-Optimization Method of Combined Tomography of Seismic Refraction and Resistivity Data

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Andy A. Bery
Keyword(s):  
High Resolution ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Optimization Method ◽  
Detailed Knowledge ◽  
Data Sets ◽  
Geophysical Surveys ◽  
Data Points ◽  
Geophysical Imaging ◽  
Seismic Refraction Data

This paper discussed a novel application called merge-optimization method that combines resistivity and seismic refraction data to provide a detailed knowledge of the studied site. This method is interesting because it is able to show strong accuracy of two geophysical imaging methods based on many of data points collected from the conducted geophysical surveys of disparate data sets based strictly on geophysical models as an aid for model integration for two-dimensional environments. The geophysical methods used are high resolution methods. The resistivity imaging used in this survey is able to resolve the subsurface condition of the studied site with low RMS error (less than 2.0%) and 0.5 metre electrodes interval. For seismic refraction method, high resolution of seismic is used for correlation with resistivity results. Geophones spacing is 1.0 metre and the total number of shot-points is 15, which provides very dense data point. The algorithms of merge-optimization have been applied to two data sets collected at the studied site. The resulting images have been proven to be successful because they satisfy the data and are geometrically similar. The regression coefficient found for conductivity-resistivity correlation is 95.2%.

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