A qualified geophysical company is capable of providing a wide range of geophysical surveying services, though typically specialize in either ground or airborne acquisition. The capabilities of a geophysical company are contingent upon their years of survey experience within the field of geophysical exploration as well as their dedication to quality QA/QC and good field practices to achieve quality data and therefore quality results.
Significant modifications to aircraft, and specialized data acquisition systems are required to obtain consistently accurate survey data. Aircraft undergo months of modifications which ensure that the aircraft is "magnetically quiet” for survey operations. Modifications include isolating generators, removing ferrous materials and removing and regularly degaussing potentially magnetic parts.
Geophysical companies field on-site geophysicists who review the flight data on a flight by flight basis to ensure quality control and good calibration practices prior to forwarding each flight's data to the company office for in-house final data processing.
The information obtained during a geophysical survey is often the instigating factor in an extensive mineral exploration project. As such, it is of upmost importance that the data meets industry standards. Subpar survey data is costly and may result in missed opportunities or potentially even wasted expenditures on areas which do not warrant further exploration.
Therefore, mining companies should research the capabilities and qualifications of geophysical survey companies prior to awarding a survey.
Factors to consider when researching geophysical companies are experience, sophistication of aircraft and the quality of the data acquired by that particular geophysical system.
Unlike a regular aircraft, those used in airborne geophysical surveys will have specific modifications designed for each specific type of geophysical survey.
Small aircraft such as a Terraquest's Cessna 206 use fixed-wing horizontal gradiometer magnetics for detailed surveys that are used to detect magnetic anomalies. The measured horizontal gradient data that is acquired has the following benefits:
- Can detect precise location of dykes, faults and contacts
- Can discriminate between small geological sources and cultural sources
- Can identify the magnetic axis within magnetic units
- Can identify the precise location of small anomalies between flight lines
In an airborne magnetic survey, a sophisticated data acquisition system will have the following characteristics:
- Real time graphical display
- Multiple analog inputs
- No need for post-flight corrections (an inability to correct post-flight data can render an entire survey useless)
- Immediate notifications of aircraft's magnetic signature
- Magnetic dropouts can be corrected as soon as they occur
- Flight path planning
These are just a few of the important aspects to consider when sourcing a geophysical company.
Geophysical surveys are beneficial tools in gathering information for geophysical mapping, as well as mineral prospecting. Quality data obtained from a magnetic geophysical survey can indicate magnetic anomalies where valuable resources and commodities are beneath the Earth's surface. Electromagnetic (EM) surveys are capable of acquiring data regarding nonmetallic resources and their concentrations below clay-ridden rock, groundwater and bedrock.
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