Borehole seismic survey for mineral exploration: Case histories from Norman West and Halfmile Lake

Borehole seismic field tests were conducted over two sub-economic massive sulphide deposits located in Norman West, Ontario, and Halfmile Lake, New Brunswick, to assess the usefulness of this technique for the exploration of base metal deposits. The field tests were conducted by the Downhole Seismic Imaging (DSI) consortium, a consortium initiated by the Geological Survey of Canada, Canadian mining and services companies (Falconbridge, Inco, Quantec Geoscience, and Noranda), and universities (University of Western Ontario, University of Alberta, Memorial University, Christian Albrechts University in Kiel, Cambridge University, and University of Helsinki) to demonstrate the utility of downhole seismic methods for exploration of massive sulphide deposits within areas of steeply dipping stratigraphy. Several aspects of borehole seismic methods applied to mineral exploration were studied and investigated by the consortium and its partners. These included physical rock properties of ore and host rocks, numerical modelling of the seismic response from orebodies, field acquisition techniques and survey design, imaging, and interpretation. The intent of this paper is to give an overview on how these aspects were integrated during various phases of downhole seismic surveys at
Norman West and Halfmile Lake.
The Norman West deposit is located within the Sudbury Igneous Complex (SIC), which comprises norite, gabbro, and granophyre cropping out in a roughly elliptical ring. Unfortunately, some of the country rock lithological units in this area are as reflective as the massive sulphide lenses, thus reducing the chances for direct orebody detection with seismic methods. Many seismic reflections correlate with faults and stratigraphic boundaries logged from diamond drillcores. The Norman West deposit, or structures associated with the deposit, produce detectable seismic reflections as far away as 1500 m. However, these reflections are difficult to distinguish from fault reflections and lithological contacts near the base of the Sudbury Igneous Complex. Results indicate that borehole seismic methods can be useful for exploration in the Norman West area, but require a priori information to help the interpretation. They also show that seismic methods are appropriate for mapping promising stratigraphic horizons, such as the sublayer norite, or to define regional faults in mine planning operations.
The Halfmile Lake deposit is located in the Bathurst mining district in northern New Brunswick. The deposit contrasts significantly in impedance (the product of velocity and density) with the almost seismically transparent host rocks, making this area an excellent test site for seismic methods. Strong acoustic impedance anomalies defined from a surface 3D seismic survey previously led to the discovery of this deeply buried sulphide lens. On borehole seismic data, the Halfmile Lake deposit has a clear but relatively complex signature, showing not only P-wave reflections, but also strong reflected S-waves and mode-converted waves (see Figure). Such prominent S-waves and converted waves have not been observed or recognized previously in borehole or surface seismic data acquired over massive sulphide deposits. S-waves and mode-converted waves add complexity to the interpretation but they also provide additional imaging capabilities potentially useful to locate a deposit. The results at Halfmile Lake show that reflected S-waves and converted waves should be considered when planning a seismic survey, as well as in processing, imaging, and interpretation of seismic data to detect massive sulphide deposits.
Full Access to Technical Paper
PDF version for $20.00
Search
Sort By:  Relevance
Showing results 1 - 6
Text
Summary: This paper deals with specifying and evaluating fans for mine ventilation projects. Topics such as fan and equipment design life, operating points, and the operating conditions are discussed. Over the anticipated life of a mine’s ventilation system, the operating requirements will invariably change. Operating duties that define the range of the ventilation requirements need to be established. Apart from achieving planned operating pressure and volume range, consideration should be given to...
Publication: CIM Bulletin
Author(s): J.S. Stachulak, K.A. Mackinnon
Issue: 1084
Volume: 97
Year: 2004
Text
Summary: Gondwana coal deposits are widespread and are known to occur on four continents. Gondwana is the southern super continent that resulted from the breakup of the super continent Pangea during Late Carboniferous to Early Permian time. Gondwana was separated from the northern continent Laurasia by an equatorial sea, the Tethys. Gondwana coals are present in South America, Africa, India, and Australia. Laurasian coals occur in the United States, Canada, Russia, and Europe where they constitute the...
Publication: CIM Bulletin
Author(s): P.A. Hacquebard, M.P. Avery
Issue: 1084
Volume: 97
Year: 2004
Text
Summary: Minera Penmont’s La Herradura, which began in July 1998, is a joint venture between Industrias Peñoles, S.A. de C.V. and Newmont Mining Corporation. The mine is located in the northern Mexican state of Sonora. La Herradura consists of an open pit mine with a two-stage crushing plant and a heap leaching facility. Gold is recovered from the pregnant solution using the Merrill-Crowe process. La Herradura produces about 130 000 oz gold per year and its treatment capacity is approximately 22 000...
Publication: CIM Bulletin
Author(s): S. Cossio, J.-L. Noyola, P. González, R. Espinosa
Issue: 1084
Volume: 97
Year: 2004
Text
Summary: A number of fluidized bed applications in nickel extraction have been developed for commercial use. Five important processes have gained particular acceptance, namely, sulphide ore roasting, nickel sulphide (matte) roasting, nickel oxide reduction, laterite ore pre-reduction, and nickel chloride pyrohydrolysis. These applications all benefit from the fast reaction kinetics, high heat and mass transfer rates, and the excellent controllability of fluidized bed reactors. This paper examines the...
Publication: CIM Bulletin
Author(s): K. Adham, C. Lee
Issue: 1084
Volume: 97
Year: 2004
Text
Summary: Mill tailings with a potential to generate acid mine drainage should be properly disposed of to avoid environmental problems. Acid may be produced in a tailings site through reactions such as the following:
2FeS2 + 71/2 O2 + H2O Æ Fe2(SO4)3 + H2SO4
Fe2(SO4)3 + 6H2O Æ 2Fe(OH)3 + 3H2SO4
Although bacterial activity is known to promote the process, the principal requirement for these reactions to occur is the exposure of the sulphide mineral to oxygen and moisture. Thus, the placement of an inert...
Publication: CIM Bulletin
Author(s): T. Yalcin, M. Papadakis, N. Hmidi, B. Hilscher
Issue: 1084
Volume: 97
Year: 2004
Text
Summary: Industrial practice in mineral processing shows that an important problem in understanding and monitoring in-mill parameters is due to the lack of fundamental knowledge and appropriate sensors. However, over the last decade, DEM modelling has shown an interesting potential in describing the fundamentals of grinding mill behaviour, in improving the understanding of internal grinding mill dynamics, and in developing solutions to industrial practice. With the objective of bringing this emerging...
Publication: CIM Bulletin
Author(s): P. Radziszewski, S. Caron
Issue: 1084
Volume: 97
Year: 2004
Powered by Coveo Enterprise Search