15. 3D Seismic Imaging for VMS Deposit Exploration, Matagami, Quebec

Seismic methods in mineral exploration and mine planning: A general overview of past and present case histories and a look into the future

“…Downhole seismic surveys such as side scan, VSP and mine seismic profiling (MSP), and in-mine seismic surveys are best suited for imaging steeply dipping to subvertical structures (e.g., Price, 1974;Cosma, 1983;Wong et al, 1983Wong et al, , 1984Gustavsson et al, 1984;Galperin, 1985;Peterson et al, 1985;Spathis et al, 1985;Harman et al, 1987;Mutyorata et al, 1987;Duncan et al, 1989;Juhlin et al, 1991;Sinadinovski et al, 1995;Frappa and Moinier, 1993;Cao and Greenhalgh, 1997;Greenhalgh and Bierbaum, 1998;Urosevic and Evans, 2000;Greenhalgh et al, 2000Greenhalgh et al, , 2003Wong, 2000;Adam et al, 2003;Cosma et al, , 2007Perron et al, 2003;Bellefleur et al, 2004aBellefleur et al, , 2004bXu and Greenhalgh, 2010). They have typically higher resolution than surface seismic data, which make them attractive for delineating fracture and fault zones for mine planning or as a complement to surface seismic surveys.…”

“…Because most geologic targets have small dimensions, processing methods should aim at preserving the potential diffraction signals from these targets. Therefore, prestack dip moveout (DMO) along with poststack migration algorithms still may be more useful in hard-rock data processing and mining applications than prestack migration (e.g., Adam et al, 2003).…”

“…Lithoprobe was instrumental in establishing acquisition, processing, and interpretation approaches suitable for the hard-rock environment that is typical to several volcanogenic massive sulfide mining camps across Canada. This includes the Bathurst , Buchans (Spencer et al, 1993;Wright et al, 1994), Manitouwadge (Roberts et al, 2003), Matagami (Milkereit et al, 1992a;Adam et al, 1996Adam et al, , 1998Adam et al, , 2003Calvert and Li, 1999), Noranda (Adam et al, 1992;Verpaelst et al, 1995;Perron and Calvert, 1998), Selbaie (Milkereit et al, 1992b;Perron et al, 1997), Sudbury (White et al, 1994;Wu et al, 1995;Adam et al, 2000;Milkereit et al, 2000), and Thompson (White et al, , 2000 mining camps. During Lithoprobe, seismic reflection methods were proposed as a deep exploration tool that could improve the knowledge of structures and stratigraphy in existing mining camps, but also to provide drilling targets at depths beyond those achieved with conventional geophysical mining methods.…”

3D reflection seismic imaging for open-pit mine planning and deep exploration in the Kevitsa Ni-Cu-PGE deposit, northern Finland

“…For the conventional processing, we used a prestack DMO and poststack migration algorithm. Such a processing strategy has been successful in the past for imaging complex structures in mining areas, and also allows diffractions to be preserved that might originate from faults or smaller bodies (e.g., Adam et al, 2003;Urosevic et al, 2005;Malehmir and Bellefleur, 2009). The key processing steps prior to stacking the data involved: The processing area has been chosen to be larger than the actual acquisition area to preserve steeply dipping reflections at the margins of the seismic cube and to reduce migration artifacts.…”

“…To our knowledge, there is no 3D reflection seismic survey conducted for deep open-pit mine planning. Three-and twodimensional reflection seismic surveys have, however, been used for the exploration of deep-seated mineral deposits with several examples from Canada, South Africa, Europe, and Australia (e.g., Milkereit et al, 1996Milkereit et al, , 2000Salisbury et al, 2000;Adam et al, 2003;Pretorius et al, 2003;Malehmir et al, 2007Malehmir et al, , 2009aMalehmir et al, , 2009bMalehmir et al, , 2011Harrison and Urosevic, 2009;Bellefleur, 2009, 2010;Dehghannejad et al, 2010Dehghannejad et al, , 2012Cheraghi et al, 2011;Juhojuntti et al, 2012). Kevitsa, our study area, is a large nickel/copper deposit hosted by a massive ultramafic intrusion in northern Finland (Figure 1) with measured and indicated resources of 240 million tons (using a nickel cutoff grade of 0.1%) grading 0.30% nickel and 0.41% copper.…”