Altamira Gold Corp. (TSXV: ALTA) has begun exploring for copper on its more than 200 sq. km land package in the Juruena Mineral Belt of eastern Brazil’s Para and Mato Grosso states. The initiative marks an expanded vision for the Vancouver-based company, which had previously focused solely on gold exploration on that same land.
Several of Altamira’s properties have tested positive for copper grading 1% or higher.
Grab samples at the Paulinho Troca Tiro prospect at the Apiacás gold project returned indications of copper. When the company re-examined data from its Firmino gold project it found 1 metre grading 1% copper from a historic drill hole.
Similarly, upon re-examination of previous drill holes at its Colíder gold project, it found intercepts grading 1.05% copper and 18.59 grams gold per tonne over 4.1 metres as well as 0.61% copper and 6.1 grams gold over 2.9 metres.
Recent re-interpretation of geophysical data from its flagship, 190 sq. km Cajueiro gold project has indicated 14 targets with magnetic and radiometric responses that may be consistent with porphyry-style mineralization at depth. Altamira believes that a concealed copper porphyry system at depth could explain the extensive gold mineralization observed on surface at Cajueiro.
Altamira will explore these targets in the coming months once the seasonal rains in central Brazil clear up.
Altamira focused on copper exploration after Anglo American plc (LON: AAL) began staking claims in the Juruena Belt in September 2017, causing “a bit of a staking rush, to put it mildly,” says Altamira President and CEO Michael Bennett.
Since then, Anglo American along with Nexa Resources SA (TSX: NEXA-T) and Vale SA (NYSE: VALE) have staked 35,000 sq. km over the Juruena Belt.
Bennett notes that Altamira is one of the only public companies holding an “extensive land package” in the area.
The first indications of a porphyry type system in the belt were reported in a University of Campinas study published in December 2015. Researchers from the university looked at an area in the eastern part of the belt called Jaca and found mineralization and alteration consistent with a copper porphyry.
Bennett says one reason no one found mineralization in the area sooner is that until 40 years ago, the area was completely covered in jungle. Then, the government built roads into the area which is now predominantly used for cattle grazing.
“At the same time the Brazilian government decided to open up population centers in the area, the local miners came in and discovered gold,” says Bennett. “Development in the area in the 1970’s and 80’s was rather uncontrolled. No mining company would have been able to do any work because there were just too many of these local guys on the ground at the time.”
Altamira originally took an interest in the Juruena Belt because of the local miners’ success. Then, with the rapid expansion of infrastructure, the area became an ideal place for Altamira to explore.
Bennett says the only way to get into Cajueiro in the 1970s was by small fixed wing planes. Now Altamira can fly from São Paulo to a commercial airport in Alta Floresta, and then drive less than 90 minutes on paved or well-maintained gravel roads.
“As a result, little modern-day exploration has been carried out on this belt,” says Bennett.
Altamira has 12 projects in the Juruena Belt. Its most advanced one, Cajueiro, contains 8.64 million indicated tonnes grading 0.78 gram gold for 214,000 oz. gold and 10.9 million inferred tonnes at 0.8 gram gold for 282,000 oz. gold as of a 2016 resource estimate and an additional 1.3 million inferred tonnes grading 1.61 grams gold for 79,000 oz. gold in the saprolite.
Metallurgical testing on ores from the Cajueiro project has shown that gold recoveries of up to 96.2% are possible using conventional leach technology.
Exploration permits on the main Cajueiro property have now been converted to mining titles.
Exploration during 2017 identified new east-west structures on the central part of the property, with gold grades being considerably higher than what has been seen on the Cajueiro project previously.
The next stage of exploration will encompass some 3,000 metres of trenching during the first half of 2018 to prepare for the next drill campaign.
“We’ve got a significant number of gold-in-soil anomalies that we haven’t even been trenched yet,” says Bennett. “There is huge upside for this to become a very important gold project without taking into account the copper potential.”
Shares of Altamira are currently priced at 21¢ with a 52-week range of 21¢ to 24¢. The company has a market capitalization of $10 million.