Gold-oriented Aurania Resources (TSXV: ARU) is finding as much copper as gold in the early innings of exploration at its Lost Cities–Cutucu project in southeastern Ecuador.
In January the junior explorer reported grades ranging from 0.9–9% copper from eight grab samples of rock in streams at its Tsenken-A porphyry target. Highlights included 9% copper with 185 grams silver per tonne and 7.1% copper with 19 grams silver per tonne.
The streams drain an area that has a geophysical signature on the edge of a large magnetic feature at Tsenken.
Copper mineralization at Tsenken-A has been found in a 3 by 1 km area, and the company says its exploration concept defines a porphyry body intruding a sedimentary and volcano-sedimentary sequence, with fluids from porphyry infiltrating and mineralizing the permeable sedimentary and volcano-sedimentary rocks.
The Tsenken magnetic feature lies 8 km from Aurania’s Kirus magnetic feature, where copper grades of up to 5.39% copper with 54.5 grams silver per tonne were obtained, and 12 km from Jempe, where the company found grades of up to 3% copper and 47 grams silver per tonne.
At Jempe, the company has reported grab samples from rocks running as high as 325 grams silver per tonne, 48% zinc and 39% lead. The samples were taken from the Shimpia target — situated between Aurania’s Tiria epithermal gold-silver target and the Jempe copper porphyry zone — and were reported in November 2018. (Shimpia lies within a fault-bounded area that is linked with the magnetic zone appearing in geophysical data at Jempe.)
“It is early days yet, but I believe it is very significant that our geologists are finding secondary copper minerals in proximity to our magnetic targets,” Keith Barron, Aurania’s chairman and CEO, said in a press release, noting that the company’s approach to copper-gold exploration has been to focus its geochemical and prospecting program on targets from an airborne geophysics survey in late 2017.
Porphyry characteristics have been found at four of the five magnetic features the company has investigated so far.
“Our findings would suggest that in the Cutucu, copper blankets have been at least partially preserved over a 20 km wide area, and that substantial copper enrichment and natural upgrading has taken place,” Barron said. “Elsewhere in the world, such as at Morenci in Arizona, the primary porphyry mineralization at depth is not economically interesting, but the enrichment blanket has sustained production for many years. We are very encouraged.”
At its Kirus target, grab samples of rock returned 4.83% copper and 58.8 grams silver per tonne, and 4.28% copper and 48.4 grams silver per tonne. Another sample — 1.5 km southwest — returned 5.3% copper and 79 grams silver. The samples were all found in rivers that flow northward off the area of strong magnetism represented at Kirus.
Copper is present as the minerals chalcocite, cuprite and malachite in slabs of fine-grained, bedded tuffs and sedimentary rocks.
“We’re a gold-oriented company, obviously, but we’re talking more about copper and silver than anything else, and that’s the nature of the beast,” Richard Spencer, Aurania’s president, tells The Northern Miner in an interview. “Copper targets are probably going to advance a bit quicker than the gold ones, because the geophysics haven’t been that helpful with gold. But we started drilling … on a gold target, and it’s epithermal. It is a much more difficult thing than walking up to copper you can see on surface, and sampling them. So the drum that we’re beating is to expect copper over the short-term, and over the long-term, things will balance out between gold and copper.”
One of the most exciting things, Spencer says, is that Aurania has “a coherent land package” and has seen continuity between intrusive-related or porphyry styles, with a lot of copper porphyry targets, as well as replacement or mantos-style silver-zinc-lead — which is quite well-known in northern Peru, but not yet known in Ecuador — in addition to epithermal systems with gold and silver targets.
“We’ve seen this whole spectrum of related commodities,” Spencer says, adding that the company has 16 targets so far, 11 of which are epithermal, and plans to drill between six and eight targets this year.
“We’ve just started scout drilling and we will drill a handful of holes in each target,” he says. “The first drilling will be at Crunchy Hill, our first epithermal target, and then the next three or four after that will be epithermals as well, and then we have to start looking at copper and silver targets, too.
“The concept is to use scout drilling as our primary means of ranking the targets and seeing which ones fit our profile best, and which ones we can most efficiently advance. And there might be a bunch of targets, especially copper-silver ones, that would be best advanced in the hands of a major or a joint-venture.”
Spencer notes that interest in Aurania’s project at the Prospectors & Developers Association of Canada convention this year was as strong as ever.
“I don’t think our booth was empty for one minute — it was quite mind-boggling,” he says. “Last year ours was a bit of a conceptual play, and this year we’re starting to get more real and demonstrate results to people. Last year we were talking about this mineralized trend we were on — an extension of an existing belt — and this year we could start to point to results.”
Of course, he adds, “everyone would like us to go faster, and so would we, but going fast means more money in the ground, which is good, but money is the fundamental issue. But we’re getting pretty good support from our shareholders.”
At the end of January, Aurania announced a rights offering to raise up to $6.4 million, and Barron committed to backstop up to $4 million of it. Under the offering, shareholders could subscribe for a common share for $2.70 per share — a 15% discount to the company’s share price as of Jan. 28. The funds will be used for exploration expenses, including scout drilling, concession fees, and general and administrative purposes.
As for working in Ecuador — Spencer is a big fan.
“There are some headaches, as there are in many jurisdictions, but we’re seeing a real move towards ministers who are economics-driven,” he says. “They’re being moved into key positions, and they’re not necessarily politicians. They are people from the business world who can get things done, and there’s a real drive to get the economy turning and more jobs, and really grow the economy, and mining is one of those key industries that the government recognizes — with a little bit of stimulus — can have a hugely positive impact on the economy.”