Airborne Electromagnetics Surveying 50 Years of Discovery and Still Going Strong

摘要

Airborne electromagnetics (AEM) surveying has been the most successful mining geophysical technique devised. Canada has enjoyed the greatest discovery success using AEM, with over seventy deposits having been located in the last fifty years (Witherly 1999). The AEM technique has also shown an enormous versatility over time, having been successfully adapted to search for a variety of ore types, deposit styles and geographic settings. The AEM technique was developed in the late 1940s to help screen magnetic anomalies in the then juvenile Thompson Camp. This first application of AEM was critical to the discovery in the mid-1950s of the very significant Thompson nickel orebodies. Over next 25 years, AEM drove discovery in all the major volcanogenic massive sulphide camps of Canada. In the mid-1970s, explorers in the Athabaska Basin found that AEM could help them to map the conductive shears often found in close spatial association with the target uranium deposits. Then, in the early 1990s, AEM played a key role in helping target the diamondiferous kimberlite pipes located in the central Slave Province of the NWT. While much of AEM's success in the first 50 years has been within Canada, the techniques' proven efficacy to help in the discovery of a range deposit types in variety of geographic settings has set the stage for AEM to become a globally significant contributor to minerals discovery in the next 50 years, whether on the Altiplano of South America, the jungles of central Africa, the high deserts of Asia or pushing deeper into the prospective mineral belts of Canada