Mineral Geophysics - Two Decades of Change

Abstract

Over the last couple of decades, mineral geophysics has benefited from well documented advances in various technologies. Airborne gravity gradiometry, DGPS, GIS integration, radiometric noise reduction, 3D electrical / seismic acquisition, 3D inversions of potential field and electrical data are particular examples. These have been partly enabled by advances in computing technology, including faster data processing and expanded storage options, email, internet, mobile and satellite telephony, and the move towards industry standard software and data formats for the vast quantity of government and open file data now available in some countries. Less documented are the extra demands placed on mining company geophysicists. Examples include formulating safety management plans and auditing air safety compliance, monitoring field safety as much as technical details and complying with relevant legal restrictions in different jurisdictions. All the while the modern geophysicist must stay abreast of an increasing number of software applications, ensure quality communication with geologists on issues of target generation and method limitation, while geophysical staff numbers have typically decreased. The vast amount of data available in the 21st Century has added to the importance of 'sorting the wheat from the chaff'. Geological and geochemical ideas have also evolved over the last two decades, and geophysicists must understand terms such as IOCG, porphyry and low-sulphidation epithermal. Geophysical responses and tools need to be evaluated for each deposit style and an objective and critical consideration maintained to constantly review whether the exploration model is appropriate or too restrictive. Pushing the search to new frontiers by proposing new, deeper and more conceptual targets as a part of the exploration portfolio is important to help limit excessive revisitation of previous outcropping targets. As for the next 20 years, some possibilities include more airborne methods, UAVs, and better models.