Environmental Impact and Economic Drawbacks of traditional aircraft geophysical surveys

Updated: Nov 14

Present Day mineral exploration faces many challenges for an already high-risk business, that is known for low success rates. But there are other challenges than economic ones, if you follow the news these days you will see global attention to the climate summit COP27, group of world leaders, industrial key personnel, and environment activists all gather to push for a decrease in the global emissions


ROSOR Blog Present Day Exploration post cover image

We will discuss the present and future of mineral exploration, especially the developments in airborne geophysical surveys. We'll start with an overview of present-day exploration, looking into current gaps in the discovery phase of mining projects and the kind of impact it has downstream. From there, we'll get into the future of exploration, showcasing emerging technology in specialized data acquisition, and providing a deeper comparison to traditional methods.

We will start with this post and the posts to follow.


Our main points today


Exploration to this day has experienced tremendous growth, largely due to the capabilities of traditional aircraft in conducting airborne surveys.


Historical perspective on airborne geophysical surveys

Present-day traditional aircraft geophysical survey

Missed Opportunities

Modern airborne geophysical survey options

Environmental Impact and Economic Drawbacks of traditional aircraft geophysical surveys

What's next?

 

Historical perspective on airborne geophysical surveys


The roots of successful airborne electromagnetic system development date back to the early 1950's when the International Nickel Company produced the world's first practical airborne EM system (Cartier and others, 1952). This apparatus, which was originally installed in a wooden aircraft to ease development problems, clearly proved the potential of the new exploration technique. Other developments of the 1950s included the Finnish two-frequency quadrature system (Puranen and others, 1960) that used a towed bird and provided compensation for the metal in the aircraft. It was operated in Canada by the Photographic Survey Corporation, a subsidiary of the Hunting Group. This system was quite effective but suffered from noise associated with conductive overburden.[1]

Figure 1. Synoptic diagram showing early AEM system. Transmitter coil (24) is powered by oscillator (26). Towed receiver coil (27) is connected to detector electronics (30, 31). Modified from Davidson (1953).
Figure 1. Synoptic diagram showing early AEM system. Transmitter coil (24) is powered by oscillator (26). Towed receiver coil (27) is connected to detector electronics (30, 31). Modified from Davidson (1953).


Present-day traditional aircraft geophysical survey


After these many years, and as the number of airborne surveys increases, so do the complications it has during and post-acquisition. In the initial phase of discovery, emphasized large middle exploration initiatives have utilized traditional aircraft platforms such as helicopters and airplanes to conduct the first round of airborne surveillance. These surveys cover large areas of interest that require anywhere from (1,000 to 10,000s) of inline kilometers. The surveys include onboarding sensors such as magnetic, electromagnetic, radiometric, and many others, however, when integrated into traditional aircraft, the performance of its readings decline due to the aircraft's requirement to fly at higher altitudes.

Sketch of a typical airborne EM survey system (time domain).
Fig. (2) Sketch of a typical airborne EM survey system (time domain).

Missed opportunities

Missed Opportunities clipart

Now, if there are fewer, less obvious deposits within the specific areas of land, those deposits can even go completely unnoticed with low-resolution traditional aircraft scans, which are less likely to be further investigated on the ground. This presents a serious problem for those involved as this can present a huge opportunity cost.


Modern Airborne Geophysical survey options


let's take a deeper dive into traditional aircraft and compare its features to the prevailing alternative of remotely piloted aircraft systems or RPAs for short.


Fig. (3) Modern Airborne Geophysical surveys options comparison based on Cost, Coverage, Resolution, Navigation, and Payload
Fig. (3) Modern Airborne Geophysical surveys options comparison based on Cost, Coverage, Resolution, Navigation, and Payload

At this point in time, traditional airplanes and helicopters have been the dominating platform for data acquisition, and with good reason. There are certain specifications that just cannot be beaten by alternatives, including the coverage and payload capacity for sensors.


Fig.(4) Downstream Impact of Traditional Aircraft Geophysical surveys
Fig.(4) Downstream Impact of Traditional Aircraft Geophysical surveys

For most applications in mineral exploration, it makes sense to deploy traditional aircraft more often than RPAs Currently, however, there are drawbacks to this platform, which cannot be overlooked, like lower resolution, poor navigation, and much, much higher overall cost. But what happens downstream should always also be closely looked at pilot safety. The environment and further costs in secondary investigations are required with traditional aircraft being that there are no alternatives that can address these concerns in an effective manner, we're situated with the following,

  • Safety hazards, It's challenging to fly at low heights and at low speeds, especially when situated in rough terrain. We should avoid putting pilots in these situations whenever possible, and there should be a better alternative to promote safer working conditions.

Varying surfaces affect the normal glidepath. Some surfaces create rising currents which tend to cause the pilot to overshoot the field.
Fig.(5) Varying surfaces affect the normal glide path. Some surfaces create rising currents which tend to cause the pilot to overshoot the field. Photo property of weather.gov
  • Environmental damage.

Scopes of Co2 Emissions
Fig.(6) Scopes of CO2 Emissions
  • As most of the world leaders gather these days for the climate summit COP27 to work on decreasing CO2 emissions, typical small airplanes such as the King Air Navajo Sessna 2 0 8, or small helicopters such as the Bell 2 0 6, MD 500 D and a S three 50 used in mineral exploration within this larger survey category produce on average approximately 1500 to 3000 metric tons of CO2 per year. On fuel alone, there's also the negative impact on manufacturing and the disposal of these aircrafts. This all contributes to the vast amount of Scope three emissions, which is of course the largest group that produces GHG emissions, not just in mining, but in pretty much all industries.

  • High cost and time wasted in post-processing and analysis of low-resolution traditional aircraft survey data. Geophysicists who analyze that data are in short supply and very much in demand. A widespread problem is seen across the industry, especially right now, which makes their service come at a great cost.

  • Compound Data Analysis Having to analyze the data, not only from in the air but also from a secondary data set on the ground, further compounds the problem. This makes for a very expensive and time-consuming investigation.


The question is, how do w