April 2023 – Monthly Talk

Speaker: Ken Witherly, President, Condor Consulting Inc.

Title: What Lies Beneath? A Reflection on the Porphyry Copper Exploration Model

Date: Thursday, April 20, 2023

Time: 4:30pm to 5:30pm PDT

Location: Room 111 – 409 Granville Street, Vancouver, BC, V6C 1T2


Electrical methods have been applied to the search for porphyry copper and IOCG deposits since the early 1950s. While there  is a generally accepted model of disseminated sulfides giving rise to a chargeability response, no clear association has been attached to what EM surveys may be responding to. Work in the early 1990s (Nickson 1993) showed the well-developed supergene blankets over a porphyry copper could be conductive; this observation was however, never applied formally to generally accepted porphyry targeting models. The presence of other conductive zones associated with porphyry copper deposits is even less well studied. On the geological side, while there is a vast body of literature describing porphyry copper deposits and how to discover them, in very few cases do these studies even speculate if anomalous concentrations of sulfides could be conductive. On the geophysical side, observations of unexpected conductivity associated with porphyry systems is sometimes noted but these observations typically stop short of suggesting that there could be a more general observation made that a new class of geophysical feature should be defined. The present study is felt to have gathered a sufficient number of case studies which show that a significant number of porphyry copper deposits posse a mineralogical character which can be identified with EM techniques. This thesis can have significant implications as to how porphyry copper are explored for, especially those at depths >500 m, a generally accepted cut-off for IP techniques.

This presentation is based on a similar talk given in AEGC 2019 in Australia. The talk has been updated several times since. The abstract from the 2019 talk can be downloaded below and forms a good summary.



Ken Witherly graduated from UBC (Vancouver Canada) with a BSc in geophysics and physics in 1971. He then spent 27 years with the Utah/BHP Minerals company during which time as Chief Geophysicist, he championed BHP’s programs in airborne geophysics which resulted in the development of the MegaTEM and Falcon technologies. In 1999, Ken helped form a technology-focused service company that specializes in the application of innovative processing and data analysis to help drive the discovery of new mineral deposits. In 2017, he helped establish the Women Geoscientists of Canada, a group dedicated to support early career women in the minerals industry.


March 2023 – Monthly Talk

March 2023 Monthly Talk

Speaker: Dr. Graham Banks,  Senior Principal Geologist, WSP Mining Canada

Title: Mapping Mineral Systems Under Sediment Cover: The Right Geophysics and Structural Geology at the Right Scale at the Right Time

Date: Wednesday, March 29, 2023

Time: 4:30pm to 5:30pm PDT

Location: Room 111 – 409 Granville Street, Vancouver, BC, V6C 1T2


This presentation is an expanded version of a seminar given at PDAC 2023 in the session called
Geophysics: Exploration Case Histories:


The objectives of geophysics and structural geology in mineral exploration should be to: (a) formulate exploration hypotheses to then, (b) test the existence of a mineral system, its plays and its deposits under sediment cover by, (c) sequentially narrowing the team’s uncertainty range through province, then play, then prospect, then borehole scales. To make undercover mineral exploration more efficient, the optimal combination of survey types that test objectives a to c should be applied, instead of conducting the most familiar suite of surveys.

The accompanying presentation will summarize how geophysics integrated with structural geology was used by Southern Geoscience Consultants in 2021, to assist Battery Minerals Limited focus its exploration program towards understanding the under cover geology. The project area is in the Stavely-Stawell metallogenic province of gold and base metals in Australia. The interpretation team did a gap analysis and a SWOT analysis of the existing data, built a district-scale geological framework, made a litho-structural interpretation, to then identify areas of further interest for deposit-scale targeting.

Thank you to Battery Minerals Limited and Southern Geoscience Consultants for permission to display this case study.


  • A senior principal geoscientist with 17 years in industry (copper, lithium, rare earth elements, nickel, gold, petroleum) spanning tectonic to drill core scales.
  • Evolved from a structural geologist to advisor of exploration-mining organisations: how to translate a project’s geoscience into probability of success, uncertainty, risk and value.
  • Helps clients create success-case and failure-case hypotheses before spending money and effort collecting costly data.
  • Integrates structural geology with geophysics: 10 years interpreting reflection 2D and 3D seismic; Interpret borehole image log data; Structural geology maps from aeromagnetic and spaceborne imagery.
  • A regional-scale geologist, with years of experience building district-scale geology models.
  • Integrates structural geology with mineral deposit-forming processes in sedimentary, igneous, metamorphic regions.
  • Creates professional development workshops for exploration-mining companies, geological surveys, policy-makers, universities and governments: exploration risk and value.
  • An external advisor on the European Union’s lithium exploration program.
  • Senior Principal Geologist, WSP Mining, Canada.
  • Director of Route To Reserves Consulting Inc.
  • Associate of Southern Geoscience Consultants.
  • Ph.D. Structural and igneous geology of VHMS deposits. Cardiff University, U.K.
  • BSc. Geology. 1st class with Honours. University of St. Andrews, U.K.








A recording of this talk is available on our Youtube channel.

Guidelines for drones in geophysics

BCGS is pleased to support an initiative that provides guidelines for geophysical uses of drone technology. Drone Geoscience LLC has generously prepared a website with guidelines for using drones for geophysics.

See also our “Drones” page, under the “Resources” menu, or review materials from the BCGS drone workshop from May 2022.

Thanks are extended to Ronald S. Bell, Senior geoDRONEologist & Geophysicist with Drone Geoscience LLC.

February 2023 – Monthly Talk

Speaker: Dr. Mengli Zhang, Research Associate,  Center for Gravity, Electrical, and Magnetic Studies (CGEM), Colorado School of Mines

Title: Efficient geophysical data acquisition using ergodic sampling: Non-linear relationship between information sampling ability (ISA) and number of samples

Date: Thursday February 23, 2022

Time: 4:30pm to 5:30pm PST

Location: Virtual. Zoom link will be distributed via our newsletter in advance of the talk. Contact info@bcgsonline.org if you would like to attend but did not receive the newsletter with link (sent February 21, 2023).


Geophysicists use difference tools such as data display, modeling, and inversion to image subsurface of the earth. The denser the data are, the more details of earth model we can obtain. The price we pay for denser data is of course the higher cost for acquisition, especially for 3D data. We may default to an implicit assumption that the resolution of our earth model is linearly dependent upon the number of samples we can collect for geophysical data. This assumption may be rooted in Nyquist sampling theory. However, Nyquist sampling theory is a sufficient but not necessary condition. We have re-examined the necessity of such dense sampling in geophysical data acquisition and developed an ergodic sampling method and shows that the number of samples has a non-linear relationship with the information sampling ability (ISA). In contrast to Nyquist sampling, which requires a sufficient but larger than necessary sample set, ergodic sampling only acquires the core subset of samples that is both necessary and sufficient to gather the same information. Therefore, ergodic sampling can significantly decrease the number of samples compared with Nyquist sampling. We present our new sampling theory and demonstrate its application in the geophysical data acquisition. Our simulation and field data example show that the cost can be reduced by a factor up to 10. Equivalently, this result also means that it is possible to acquire 10 times more information when the same number of samples used in the traditional equi-spaced sampling is deployed using the ergodic sampling strategy.

Dr. Mengli Zhang is a Research Associate in the Department of Geophysics at Colorado School of Mines. She is a geophysicist specialized in optimization of the exploration cycle from acquisition, interpretation, to discovery by incorporating economic factors. She is also an expert on efficient and economical multi-geophysical data acquisition using ergodic sampling theory. She obtained her BS in Information Engineering and MS degree in Information and Communication Systems from Xi’an Jiaotong University in China. She earned an MS degree in Geoscience from the University of Texas at Dallas, USA, and PhD degree in Geophysics from Colorado School of Mines. She has 10 years of industry experiences, first as a research geophysicist and then as a project manager and as Chief Geophysicist in the eastern Ordos Basin for China National Petroleum Corporation, where she applied information analyses to increase gas reservoir discoveries. She worked closely with geologists to select locations of more than 500 drilled wells, perform post-drilling analyses throughout the life cycle of wells including the production stage, and to improve interpretation and targeting methodology based on drilling and production results. Her current research has applications to the information-based economic geophysical data acquisition, which has the potential to significantly reduce the cost of exploration for energy and metals and to accelerate discoveries.

BCGS Roundup Breakfast 2023

BCGS Roundup Breakfast – January 24, 2023

Speaker: Michael (Max) Maxwell, Ph.D, P.Geo., RMC. Senior Geophysicist

Title: Highlights of 40 Years of Shallow Geophysics: A world tour with stops from Arctic to Antarctic, -50C to +50C and -1000m to +5000m

Date: Tuesday, January 24, 2023

Time: 7:30am – 9:30am PST


Coast Coal Harbour Vancouver Hotel
Coal Harbour B Room
1180 West Hasting St.
Vancouver, BC, V6E 4R5

Registration: Industry $45 / Student $20

Please register and pay via Paypal at the link below.
Registration closes on Fri, Jan 20 @ 4pm. Space is limited so register early!

Please note. We have currently sold out! (As of Jan 19 @ 12:30pm). We are looking into increasing the number of spots.


Highlights of 40 Years of Shallow Geophysics: A world tour with stops from Arctic to Antarctic, -50C to +50C and -1000m to +5000m
Michael (Max) Maxwell, Ph.D, P.Geo., RMC

I will provide an overview of interesting geophysical experiences, surveys, techniques, and instrumentation that comprise the involvement of myself and a long list of collaborators, in shallow engineering and environmental geophysics investigations over the past 40+ years. The expansion of our capabilities in applied shallow geophysics has been rapid building on contributions from industry and academic developments. Improved instrumentation and interpretation have moved us rapidly from 1D to 3D imaging and continue to advance the speed and resolution of our shallow surveys.

After a decade of research and consulting in applied glaciology and shallow exploration methods, I was fortunate to join the engineering and environmental world of Golder Associates to expand on methodology that was pioneered by oil and gas and mining geophysicists through the sixties and seventies and that continue to be developed. We have completed marine and terrestrial geophysical surveys on all seven continents from the height of Andes and Asian mountains to the depths of Saskatchewan potash mines. We have had the opportunity to develop new survey techniques from simple cable and pipe location work to underground and surface 3D ERT techniques in conjunction with research partners around the world.

I will review a sampling of some of the more interesting aspects of instrumentation, interpretation and applications that we have encountered.

About the Speaker:

Dr. Maxwell has more than 45 years of experience in geophysical surveys around North America and internationally. He has conducted geophysical investigations on diverse mining, geotechnical, and environmental projects ranging from small to large scale, including pipeline and road routing, hydrocarbon, contaminant and other hazard detection, marine port and linear infrastructure surveys, underground mining exploration, and mining and infrastructure development. He has extensive experience in various environments including arid and cold regions, mountain, arctic and Antarctica surveys, marine and terrestrial work, underground and surface mining. Dr. Maxwell also continues geophysical research work in a range of geophysical techniques and particularly 2D and 3D ERI through his affiliation with the University of British Columbia as an Honorary Research Associate. The 3D ERI application work includes 3D imaging of water flow in tailings and power dams.

Representative projects that he has worked on include terrestrial and marine site and routing work for mining and oil and gas companies, road, landfill, geotechnical and infrastructure surveys for numerous industrial and government clients, domestic and international oil and gas, mining development work, environmental surveys for large and small industrial, federal, and municipal clients, ice runways in Antarctica, and mountain hazard evaluation of glaciers, snow avalanches and ice-dammed lakes for locating infrastructure. His clients have included Newmont, BHP, Teck, Cameco, Rio Tinto, Barrick, Diavik, Dominion, De Beers, Shell, Exxon-Mobil, BG-Spectra, Hunt Oil, Pluspetrol, Pembina, KLNG, Trans Mountain, Kinder Morgan, Moffatt and Nichol, and others. He was the Division Manager overseeing Golder’s Geophysical Services Group in Vancouver and is a registered Professional Geoscientist in British Columbia, Northwest Territories and Saskatchewan. He provides technical review and oversight for Golder Geophysical work from offices around the world.