Johannesburg-based airborne geophysics technology provider Spectrem Air will later this month explore 6 000 km2 for an Australian mining company in Western Australia using its airborne geophysics Spectrem Plus system.

Spectrem Air has been in discussion with potential clients since the beginning of the year, with most looking at new exploration potential in areas that have been previously investigated.

The company will use its specialised technology system to determine the conductivity of the rocks and make a geological map of the area using its specially modified turbine DC3 Spectrem Plus airborne electromagnetic system.

The plane will be operated for about five days a week, depending on the weather, aviation regulations in terms of pilot duties and how often the aircraft can be maintained and serviced.

Spectrem Air GM Louis Polomé says the area being surveyed is unpopulated, dry and mainly sand-covered. It is also poorly developed, which could generate challenges, as there are not too many facilities nearby from which to operate and service the plane.

“Our main challenge is logistics. To take the system to Australia, we first need to fly the aircraft from South Africa to Australia with all the equipment on board and then find a local airport with all the necessary support and maintenance from which we can operate. These kinds of facilities are hard to come by in an area as uninhabited as Western Australia.”

Spectrem Air’s modernised aircraft is suited for these long ferry conditions. The aircraft has a seven-hour “survey flight” endurance, depending on terrain. This allows it to cover vast areas quickly,

says the company.

Nonetheless, the hostile conditions make airborne geophysical exploration an easier alternative, compared with ground exploration. Surface cover can be very conductive and thick, making traditional ground geological or geophysical exploration mapping difficult.

Polomé points out that Spectrem Air continuously advances the functionality of its system by upgrading hardware and sensors. Technological improvements have resulted in the system achieving increased depth of penetration – more than 800 m below the surface – and greatly enhanced geological resolution, while maintaining a high level of detail in the near-surface geology.

In addition, while most mines seek to start their operations as shallow as possible, the information from the deeper regions to be mined can provide critical geological insight and allow for advanced planning regarding possible deep mining developments in future.

Why Australia?
Polomé notes that, owing to the major downturn in mining and exploration in South Africa, Spectrem Air is focused on international projects, especially in Australia, where exploration spend is steadily increasing.

“It makes sense for us to pick up this wave of interest in expenditure on exploration.”

Polomé adds that the company has completed several projects in Australia for mining companies Anglo American, BHP Billiton and the Common- wealth Scientific and Industrial Research Organisation, from 2009 to 2010, and again from 2012 to 2013, with great success.

Squid Showcase
Spectrem Air plans to announce the commercial launch of its superconductor magnetic gradiometer, the Full Tensor Gradient Squid Magnetometer, at a South African Geophysical Association conference on September 10 to 13, at the Lord Charles Hotel, in Cape Town, next month.

The Squid system is in the final stages of commissioning, which involves testing, the evaluation of and modifications to the sensors, as well as the processing of a large amount of data.

“We have tested the technology in-house, we know what the results are and we have built up trust and confidence to take the Squid system to commercial market early next year,” Polomé highlights.

This system, which enhances the capability of sensors used in airborne geophysical systems used to determine the magnetic properties of rocks and produce a geological map thereof, is being tested at Spectrem Air’s facility at Lanseria, in Johannesburg, and has been in development since 2010.

The Squid system was originally developed for military and medical applications; however, Spectrem Air has secured exclusive use of the technology for application in mineral exploration, which was developed by a Germany-based research centre The Leibniz Institute of Photonic Technology.

Airborne Advantage
Airborne geophysical surveys use several different sensors to measure certain physical properties of rocks, including density, magnetism and conductivity.

This information, converted into a geological map, guides mining exploration programmes and also assists in solving geotechnical issues and monitoring environmental elements such as underground water.

Polomé earlier this year told Mining Weekly that compiling the measurements in the air results in faster decision-making and is a relatively cheap form of acquiring data.
The information is also gathered nonintrusively, causing no disturbance to the area.

“The unique mapping tool incorporated into the design of the technology and the power of the sensors make the system especially suited to exploring and mapping deep geology, which is typical of many mining environments in Africa and Australia.”

Spectrem Air combines this technology with a complete service offering, which, Polomé says, includes a highly experienced in-house geophysical group of expertise, providing assistance for mining companies from the early stages of project planning to the generation of a detailed three-dimensional geological model.

“Our team comprises experts in a range of fields, including aviation technology, electronic technology and geophysics. The integration of this knowledge enables us to fast-track technological development, as we aim to keep South Africa at the forefront of innovation in airborne geophysics,” he concludes.