Nevada means never being out of sight of a headframe

Moira Smith has clocked more than a decade working on gold and copper projects in Alaska, Panama, Argentina, Mexico and Peru. But the senior geoscientist says Nevada “leads the pack” in terms of gold mined per unit area.

“There is such a big endowment of gold in Nevada that your chances of making a discovery here are probably higher than just about anywhere else in the world,” she points out during a three-and-a half hour drive southwest of Elko to visit Fronteer Development Group’s (FRG-T, FRG-X) Northumberland deposit.

If Nevada were a country, it would be the fifth-largest gold-producing area in the world behind South Africa, Australia, China and Peru.

“The revenue coming out of here is staggering,” she says. “In Nevada, you’re almost never out of sight of a headframe.”

That’s probably not an exaggeration. The state produces about 81% of all the gold in the U. S.

Of that amount, the Carlin trend makes up a little more than half.

The trend — a 40-mile-long, 5-mile-wide zone running northwest to southeast consisting of low-grade, epithermal deposits — boasts a reserve of about 50 million oz. gold, or about 5 million oz. gold per sq. mile.

Most of the mineralization is thought to be about 38 million years old. The characteristics of Carlin-style mineralization include shallow systems where lower-grade gold occurs as disseminations in carbonaceous, limey siltstones and altered limestone and is spread out at depths of 500- 700 ft. Deeper, higher-grade sulphide gold mineralization typically occurs at depths below 1,000 ft.

But while the endowment is rich, the metallurgy can be a challenge, Smith concedes. The gold here occurs in micron- sized particles that are too small to be seen, which is part of the reason why the deposits here weren’t discovered until fairly recently.

“You can work your entire career in the Carlin trend and never see gold,” Smith explains.

The micron gold — just tiny specks in arsenical pyrite –is so fine that it can be detectable at low levels in stream sediment using sophisticated assay techniques, but “you are not going to see it in a gold pan, or in the rock.”

The Carlin trend was discovered in 1961 by John Livermore and Alan Cope, two geologists who were working for Newmont Mining (NMC-T, NEM-N).

The trend actually consists of a number of distinct extractive locations about 20 miles west of Elko, on Interstate 80 along a northwest to southeast band extending 20 miles north and several miles south of the Interstate.

The mineralization was near surface (just 25 metres down), but so finely disseminated that all traces were microscopic.

Of course, the upside is that fine gold makes it perfect for heap-leach recovery when rocks are oxidized.

Apart from the difficult metallurgy, it’s getting harder to find deposits because most of the easily recognized shallow deposits have been found already.

Now companies need to drill deeper.

Smith acknowledges that the future of the Carlin trend and other mature districts likely lies in the discovery and exploitation of deep, high-grade deposits by underground mines.

By other measures, Nevada has average to high exploration costs compared with jurisdictions elsewhere and permitting can be a tedious process, Smith points out.

Requirements for reclamation of disturbance on U. S. federal lands are strictly regulated and “are probably the most comprehensive in the world,” she says.

Mark O’Dea, Fronteer’s president and chief executive, likes working in Nevada because of its well-entrenched mining culture and mining law.

“Mining is a big part of the economy, so while the environmental and permitting regulations are strict, they’re well understood and as long as you comply, then work is feasible,” he says.

While tenure is very secure compared to most other mining regions in the world, the practice of on-the-ground staking of claims is “time-consuming, expensive and a bit archaic,” Smith says. Most other countries have adopted electronic or other methods of staking to facilitate the process.

But most areas of the state have power, rail and other amenities nearby and are road-accessible — “something that I can’t say about the other areas I’ve worked in,” she adds. That means more time and energy can be spent on exploration than on logistics.

In addition, Nevada’s benign climate, vegetation and wildlife make it an easier place for companies to sell to prospective employees — an important consideration during the current commodity boom and labour shortage.

“Nevada represents excellent bang for the buck,” O’Dea says. “You’ve got currency in your favour, endowment, low political risk, (and) good discovery upside. All those attributes mean good strong rewards for our shareholders through modest exploration investments.”