Canada may have some of the world's richest diamond deposits, but they are hard to find. Now, groundbreaking technology developed by an Ontario company could help pinpoint the deposits and possibly make Canada the world's largest diamond producer in years to come.

Mississauga-based Gedex Inc. has developed an airborne surveying system capable of "seeing" as far as 12 kilometres beneath the Earth's surface to identify precious metals, oil, gas and minerals that are invisible to current systems.

Airborne system

Gedex's system, a new twist on a century-old idea, has already won the company a mining research award, the first ever given by the Mining Journal, the authoritative 170-year-old British publication. The award was adjudicated by an international panel of experts, who cited Gedex for "primary research that is expected to have the most significance for mining and mining equipment in the future."

High Density Airborne Gravity Gradiometer (HD-AGG)

Gedex's new system, known as a High Density Airborne Gravity Gradiometer (HD-AGG), uses tiny variations in gravity to identify geological structures beneath the ground. Among the structures it can precisely spot are kimberlite pipes -- vertical columns of rock pushed upward into the Earth's crust by volcanic action far below -- that often contain diamonds.

"Some of the geologists and geophysicists we've been talking to have said to us that it's no longer like flying blind," Robbie Banks, president of Gedex, said of the new system.

It is believed there are a number of undiscovered kimberlite pipes in Canada, he said, but they are small and hard to detect. Those found so far, though -- such as the Ekati and Diavik mines in the Northwest Territories -- are rich in high-quality diamonds.

"What's important in Canada is that the kimberlite pipes are smaller than in the rest of the world, so you need a high-resolution instrument, but they're much richer and the diamonds are of a much better quality," Mr. Banks said. "It's pretty exciting to be part of the Canadian diamond scene right now."

It is perhaps not surprising that international diamond giant De Beers Group wants to use Gedex's HD-AGG system to look for more sites in Canada and for exploration in other countries as well.

"This technology promises a greater degree of accuracy than other techniques that have been employed," said Linda Dorrington, director of public and corporate affairs at De Beers Canada Inc. in Toronto.

While it appears that HD-AGG will be first used to hunt for diamonds, it could also be employed to find other valuable resources, Mr. Banks said. For example, sulphide deposits -- which often contain copper, silver, gold, zinc and other metals -- are seen much more clearly with the HD-AGG system than with older devices.

Canada has sizable sulphide deposits, Mr. Banks noted. Those found to date have been on or near the surface, making them relatively easy to find, but there may be more massive ones 100 metres or more below the Earth's surface, which the HD-AGG system could help locate.

"This opens up the whole area of mineral exploration like it's never been opened up before," said Mr. Banks.

The system might also be used in oil and gas exploration or to find underground water sources, he added. And it could have applications outside the resource industry; for example, it might be used by security forces to find hidden tunnels.

The Gedex system has its roots in the 19th century, when a Hungarian physicist named Roland, Baron von Eotvos, discovered that variations in gravitational force could help in geophysical exploration, a concept known as gravitational gradiometry. The U.S. military used his ideas to build navigation and missile-targeting systems for submarines during the Cold War.

The resource industry had tried using airborne gravitational gradiometry to look for mineral deposits, but older technology couldn't produce clear enough images, Mr. Banks said.

Enter Bill Breukelman, Gedex's chairman and founder. He has a long-standing interest in innovative image technologies, having helped found IMAX Corp., the maker of oversize, three-dimensional film technology; and Sciex, a maker of medical imaging technology that is now part of the global life sciences company MDS Inc.

In 1999, he started Gedex with support from private investors, and the privately held company now employs about 35 people.

Gedex developed its HD-AGG system by combining its own innovations with ideas from other researchers.

Mr. Banks explained that older technology used two linear accelerometers mounted on a spinning turntable to pick up minute variations in gravity. But the turntable produced bearing noise that interfered with the signal resolution. After researchers at the University of Western Australia and the University of Maryland came up with a new design that eliminated the turntable and thus the noise, Gedex licensed that technology.

With the turntable noise eliminated, the vibration of the aircraft itself became an issue. Using technology it licensed from the Canadian Space Agency, Gedex developed an isolation mount that keeps its device vibration-free.

Gedex also developed a way to use superconducting quantum interference devices, or SQUIDs, to measure tiny variations in gravity. These electronic devices work only at extremely low temperatures, so Gedex encased its instrument in a cryostat, a kind of high-tech cousin of the Thermos bottle that keeps it at roughly absolute zero.

In use in the field, an airplane carrying the HD-AGG flies over the area to be explored. A single pass can cover a strip 60 to 100 metres wide for preliminary exploration; for more detailed mapping the plane flies lower, covering less terrain on each pass.

The device measures minute gravity variations that translate into a colour-coded map of what lies beneath the ground.

For example, the system displays a kimberlite pipe as a distinct blue circle in the middle of a field of red, rather than as one of several blue blotches in a confusing swirl of colours, as with older systems. Other formations, such as sulphide deposits, also show up more clearly.

Gedex plans to form partnerships with exploration companies that want to use the system. The first is De Beers, which has signed a deal under which it is funding continued development of the technology.

This summer, De Beers expects to test and calibrate the system by flying over areas of Canada where underground geological formations are already known, and then start using it for exploration around the end of the year.