Figure 3: Seismic tomography of profiles 2 (a) and 4 (b) showing the different velocities (top diagrams) in relation to ray paths (bottom diagrams) of the subsurface lithologies.
The reflection seismic method has been successfully proven to be one of the most preferred techniques for mine development and exploration for minerals in South Africa [1]. The study aims to image the geological structures and delineate platinum reefs using active reflection seismic data collected at Tharisa mining operation, within the Rustenburg Layered Suite (RLS) of the Bushveld Complex (BC) (Figure.1).
2. Data Acquisition
3. Data Processing
ANALYSIS OF FAULT NETWORKS USING AIRBORNE ELECTROMAGNETIC DATA IN NORTHERN SHELBY COUNTY, TENNESSEE
Kapil Karki 1, Daniel Larsen1
Figure 1: Geological map of the Bushveld Complex (a), the Western limb showing the study area denoted by the star (b), and the stratigraphy of the RLS (c).
Figure 2: Acquisition equipment. (a) and (d) indicates 1C RAUs (blue arrow) and 5Hz Geophones (red arrow), (b) shows Differential Global Positioning System (DGPS) (purple arrow), and (c) shows GPEG 500 kg drop hammer (orange arrow), an observer (yellow arrow).
Figure 4: Raw (a, d, and g), and processed shotgathers (b, e, and h) examples showing first breaks (red arrow), reflected waves (blue arrow), ground rolls (purple), ambient noise (Blue blocks). (e, f, and i) frequency spectrum.
5. Conclusions
Conducting a seismic survey for data acquisition appeared to be challenging due to a noisy mining setting, however, seismic data were visible enough to identify the P-wave first arrivals, surface waves, and seismic reflections of geological structures and lithological contacts within the subsurface. A geological cross-section was created using the previous borehole dataset, which was conducted in 2022, to support the correlation of the mineralization captured on the seismic section.
4. Results
Figure 6: Post-stack time migrated section of profile 2, with clear reflections represented by R1 and R2, at a depth range of 50 m to 140 m, corelating to the borehole. Black lines show possible faults cross-cutting the reflections.
6. References
[1] Manzi, M. S., Durrheim, R. J., Hein, K. A., and King, N., 2012. 3D edge detection seismic attributes used to map potential conduits for water and methane in deep gold mines in the Witwatersrand basin, South Africa. Geophysics, 77(5), pp 133-147.
Figure 5: 3D view of migrated stack sections of six acquired profiles (a), with the 5 borehole along profile 1 (b). There are clear reflections correlating to the contacts of the borehole lithologies (c).
(a)
(b)