Mineral exploration relies upon airborne geophysical companies that specialize in conducting highly precise surveys with high resolution data acquisition and advanced data interpretation. The success of a geophysical survey is dependent not only upon the survey itself, but the ability to interpret the data obtained accurately and apply it appropriately.
Mining companies conduct airborne geophysical surveys to seek high concentrations or other indirect indications of mineable magnetic ores within the Earth's crust. These surveys can indicate the locations of commodities such as kimberlites, magnetic iron ores, petroleum, hydrocarbon, coal, and precious and base metals.
Services provided by an airborne geographical company include gathering and interpreting high-impact data, applying methods that are cost-effective and targeted for the investigation at hand. Airborne geographical surveys acquire geophysical data and map the ambient magnetic fields and their distribution. A typical airborne magnetic survey will provide a broad overview of a specific area's geology. In addition, it is possible to test and accurately measure the fluctuating magnetic signatures found in the Earth's crust.
Terraquest's airborne geophysical surveys employ the use of aircraft that have undergone thorough modifications that ensure the aircraft is "magnetically quiet” and noise-free, even during turns and other changes in the flight path. Examples of these modifications include:
- removing and de-gaussing potentially magnetic parts
- isolating generators
- removing ferrous materials
There are four key types of airborne geophysical surveys:
- Airborne radiometric surveys.
- Airborne electromagnetic surveys (helicopter time domain electromagnetic surveys - HTEM - or passive VLF-EM).
- Airborne magnetic surveys.
- Airborne gravity surveys.
The above survey types are unique in the information they gather and their flight characteristics. Airborne magnetic survey data is generally, but not always, acquired at a higher altitude and higher speed. Airborne radiometric survey data is acquired at a lower altitude and speed. Airborne gravity surveys are generally carried out at constant altitude or gentle drapes.
As an experienced airborne geophysical survey company, Terraquest provides on-site geophysicists who review the flight data on a daily basis for quality control. Accuracy in data acquisition is of upmost importance as the results of a geophysical survey are important information utilized when mining companies decide to perform ground work or drill. If the data is misleading, it can lead to wasted time and money on exploring in areas that are not profitable.
The most common airborne geophysical surveys conducted are airborne magnetic surveys. These surveys employ the use of a magnetometer that is either attached to an aircraft or towed behind. It works by measuring the variations in ambient magnetic fields. In turn, it offers direct or indirect indications as to the location of economic minerals in the subsurface.
By using an aircraft outfitted with horizontal gradiometer magnetics, detailed surveys can be flown at low altitudes to acquire high resolution, accurate and precise data. These surveys are flown to pinpoint the exact locations of commodities such as kimberlites.
A specialized aircraft combined with a modern data acquisition system increases the chances that the survey will be a successful one, acquiring valuable information that will hopefully lead to a successful mineral exploration program.
When sourcing out the geophysical services of a specific geophysical company, it is advisable to review the characteristics of the data acquisition systems and procedures that will be used. Key criteria implemented by Terraquest include:
- Flight path planning
- Real time graphic display
- Multiple channels of analog recording
- Multiple magnetometer inputs
- Adaptive signal processing techniques
- Immediate quality control
- No need for post-flight corrections
Airborne geophysical survey companies are able to provide both regional and detailed airborne magnetic surveys, and are capable of interpreting the data in a useful and accurate manner. Regional surveys are used mainly for reconnaissance mapping and detailed surveys are capable of higher resolution mineral deposit mapping.
Specialists in Airborne Geophysical Surveys
Terraquest was established in 1984 and since then, our dedicated team has flown over 1,500 airborne geophysical surveys using both fixed wing and helicopter platforms. Our professional crews provide significant experience having carried out airborne magnetic surveys, airborne gravity surveys, airborne radiometric surveys, and airborne electromagnetic surveys on five continents.
Our quality data sets have been utilized in the exploration for base and precious metals, kimberlite, hydrocarbons, uranium, rare earth minerals and water. The company has performed exemplary surveys for both small and large exploration groups as well as many government agencies. References can be provided upon request. Visit
www.terraquest.ca.
Ed. GMH