BCGS Technical Talk – February 14, 2017

Speaker : Jan Franke

Dr. Jan Francke has spent his 27-year career working solely with deep GPR systems and applications, mainly in mineral exploration.  His experience spans 86 countries in every environment, ranging from Siberia to Libya.  He has authored dozens of technical papers and book chapters on GPR and conducts workshops on long-range GPR worldwide.

Title: A review of ground penetrating radar applications to mineral exploration

Date/Time: Tuesday February 14, 2017 @ 4:30pm

Location: 4th Floor Conference Room, Room 451, 409 Granville St. (UK Building at Granville and Hastings), Vancouver

Abstract:
The interest in mineral exploration applications for GPR has risen significantly in recent years, due partly to extraordinary claims of performance made by some promoters.  Although all radar systems are governed by the same physics, advances in electronics over the last decade have enabled much deeper penetration than was previously possible, from pocket-sized wireless systems operated by iPhones.

The talk will provide an overview of GPR’s history and principles, as well as its use in mineral exploration.  A review of applications of the technology will highlight successes, with penetration to hundreds of metres in non-polar environments, as well as unexpected failures in seemingly suitable settings.

Also addressed will be recent claims of extreme penetration through any environment using “lased” EM energy or “megawatt” transmitters.  These instruments and their data will be analysed within the context of accepted physics.  The talk will conclude with an overview of the future of deep GPR, including advances such as real-time sampling, novel transmission modulations, instrument miniaturisation, multi-frequency systems, hybrid EM-GPR systems as well as new deployment platforms such as UAVs.

The BCGS Executive are pleased to provide details about the upcoming two-day Geophysics for Geologists short course at Roundup 2017 to be held on January 21 and 22, 2017.

Course Outline:

Day 1 (AM): Induced Polarization and Resistivity

Day 1 (PM): Gravity, Magnetics, and Radiometrics

Day 2 (AM): Electromagnetics and Magnetotellurics

Day 2 (PM): Inversion, Modelling, and Interpretation

The full course outline, list of speakers, individual coarse module summaries, and registration details can be found on the AMEBC Roundup 2017 website.

http://roundup.amebc.ca/events/geophysics-for-geologists/

KEGS/BCGS Roundup Breakfast – Tuesday, January 24, 2017

SPEAKER: Dr. Martyn Unsworth, Professor of Geophysics, University of Alberta

TITLE: A geophysical view of mountain building: perspectives from the Andes, Himalaya and Antarctica

DATE/TIME: Tuesday, January 24, 2017

LOCATION: Fairmont Waterfront Hotel, Princess Louisa Room, Vancouver

REGISTRATION: Online at www.kegsonline.org (Deadline Jan 20, 2017)

ABSTRACT:

Geophysical imaging has proven to be a valuable tool in understanding the geological processes that occur within plate boundaries. Magnetotelluric (MT) exploration is especially useful in these studies since it can measure electrical resistivity, a rock parameter which is sensitive to the presence of fluids such as water or partial melt. In this presentation I will describe how MT has been used to study mountain building. In subduction zones, MT has defined the pathways taken by molten rock from the mantle to the surface where it is erupted by volcanoes. It has also detected some of the largest magma bodies on Earth and shown that the melt can have a high water content. The Himalaya and Tibetan Plateau were formed by the collision of the Indian and Asian plates and MT studies have imaged regions of molten rock that are sufficiently weak to flow. A final example will focus on Mount Erebus in Antarctica, where MT data are being used to image the magma system of a volcano which is not located on a plate boundary.

BCGS Technical Talk – December 15, 2016

Speaker: Gary Tipper, Skytem

Title: New generation of helicopter time domain electromagnetic systems for mineral exploration in rough terrain

Date/Time: Thursday December 15, 2016 @ 4:30pm

Location: 4th Floor Conference Room, Room 451, 409 Granville St. (UK Building at Granville and Hastings), Vancouver

Abstract:
Advances in technology for helicopter borne Time Domain Electro-Magnetic survey systems in the last 10 years has allowed the Mining industry the ability to acquire high resolution data in areas historically very difficult to access.

This presentation will focus on some of the past and ongoing technical challenges associated with survey design, drape mode versus contour mode flying, helicopter and pilot performance, technical limitations of past helicopter AEM systems and data quality issues of previous public domain BC AEM surveys.

It will show examples of past system geometry and design, claimed system dipole moments and calculations of Effective Dipole Moments (EDM), based on the wave forms of the different commercial AEM systems, and realistic depth of investigation.

It concludes with details of the new SkyTEM AEM systems for providing high resolution data in these challenging areas and recent case study of a new generation system flying in British Columbia.

BCGS Technical Talk – November 16, 2016

Speaker: Justin Granek, PhD Candidate, UBC-GIF, Vancouver, BC

Title: Application of Machine Learning Algorithms to Mineral Prospecting Mapping

Date/Time: Wednesday, November 16, 2016 @ 4:30 pm

Location: 4th Floor Conference Room, Room 451, 409 Granville St. (UK Building at Granville and Hastings), Vancouver

Abstract:

In the modern era of diminishing returns on fixed exploration budgets, challenging targets, and ever-increasing numbers of multi-parameter datasets, proper management and integration of available data is a crucial component of any mineral exploration program. Machine learning algorithms have successfully been used for years by the technology sector to accomplish just this task on their databases, and recent developments aim at appropriating these successes to the field of mineral exploration. Framing the exploration task as a supervised learning problem, the geological, geochemical and geophysical information can be used as training data, and known mineral occurrences can be used as training labels. The goal is to parameterize the complex relationships between the data and the labels such that mineral potential can be estimated in under-explored regions using available geoscience data.

Numerous models and algorithms have been attempted for mineral prospectivity mapping in the past, and in this thesis we propose two new approaches. The first is a modified support vector machine algorithm which incorporates uncertainties on both the data and the labels. Due to the nature of geoscience data and the characteristics of the mineral prospectivity mapping problem, uncertainties are known to be very important. The algorithm is demonstrated on a synthetic dataset to highlight this importance, and then used to generate a prospectivity map for copper-gold porphyry targets in central British Columbia using the QUEST dataset as a case study.

The second approach, convolutional neural networks, was selected due to its inherent sensitivity to spatial patterns. Though neural networks have been used for mineral prospectivity mapping, convolutional neural nets have yet to be applied to the problem. Having gained extreme popularity in the computer vision field for tasks involving image segmentation, identification and anomaly detection, the algorithm is ideally suited to handle the mineral prospectivity mapping problem. A CNN code is developed in Julia, then tested on a synthetic example to illustrate its effectiveness at identifying coincident structures in a multi-modal dataset. Finally, a subset of the QUEST dataset is used to generate a prospectivity map using CNNs.