3D edge detection seismic attributes used to map potential conduits for water and methane in deep gold mines in the Witwatersrand basin, South Africa

Abstract

Inrushes of ground water and the ignition of flammable gases pose risks to workers in deep South African gold mines. Large volumes of water may be stored in solution cavities in dolomitic rocks that overlie the Black Reef (BLR) Formation, while there are several possible sources for methane, namely, coal seams, kerogen found in some gold ore bodies, or methane introduced by igneous intrusions. Potential conduits that may transport water and methane to underground workings were mapped using 3D reflection seismic data. Edge detection attributes successfully identified many faults, some with displacements as small as 10 m. Faults that displace the Ventersdorp Contact Reef (VCR) and the BLR horizons were of special interest, as known occurrences of fissure water and methane in underground workings show a good correlation with faults that were imaged on the VCR and BLR horizons. Because there are uncertainties in determining the linkage of faults with aquifers and methane sources, it is considered prudent to assume that all structures that displace the VCR and BLR horizons are potential conduits.

Integrated interpretation of 3D seismic data to enhance the detection of the gold‐bearing reef: Mponeng Gold mine, Witwatersrand Basin (South Africa)

“…However, such thinner reefs can still be detected up to λ/32 using seismic attributes (Manzi et al . ; Manzi et al . ).…”

“…; Manzi et al . ) were generated to confirm the structural information and to delineate subtle faults that fall below the seismic resolution limit (∼25 m). Prior to application of edge detection techniques, the CLR depth map was smoothed through low‐pass filtering using the combination of mean and median filters to remove noise introduced during manual picking.…”

Application of spectral decomposition and neural networks to characterise deep turbidite systems in the outer fold and thrust belt of the Niger Delta

“…Three-dimensional seismic data have found immense applications in subsurface imaging and characterisation (Aminu and Olorunniwo 2011;Manzi et al 2012;Dunlap, Wood and Moscardelli 2013). The most important application of 3D seismic data by expenditure size is hydrocarbon exploration.…”

“…The most important application of 3D seismic data by expenditure size is hydrocarbon exploration. Nonetheless, applications are diverse and include mineral exploration (Trickett et al 2004;Manzi et al 2012;Malehmir et al 2015), study of geofluid migration and geohazards definition (Bünz et al 2005;Gay et al 2007;Sultan et al 2007;Petersen et al 2010), and hard rock characterisation for carbon sequestration (Juhlin et al 2007). The proliferation of seismic attributes that have the potential to highlight subsurface features beyond what the raw seismic amplitude offers has served to further entrench the usefulness of 3D seismic data (Barnes 1999;Chopra and Marfurt 2005).…”

3D Seismic Imaging of the Ghost-Carbon Leader Reef of the World's Deepest Gold Mine - Mponeng Gold Mine, South Africa

“…This 3D seismic survey was aimed at imaging the key economic gold-bearing reefs or conglomerate units such as the Ventersdorp Contact Reef (VCR ~ 1.5 m thick) and Carbon Leader Reef (CLR ~ 1 m thick). The 3D seismic design, acquisition and re-processing are summarized by Manzi et al (2012).…”