Aura set to update Arapiraca resource

VANCOUVER–After a long delay at the lab, the final set of assay results before a resource calculation for Aura Minerals’ (ORA-T, ORAUF-O) Arapiraca project are in and look likely to bolster the size of the copper- gold-iron-nickel deposit.

Aura’s 100%-owned project is in Alagoas state, Brazil, and to date hosts one deposit: Serrote da Laje. Vale (RIO-N) — then Companhia Vale do Rio Doce — worked the project in the 1980s and 1990s, completing 90 holes for 16,897 metres. A recent estimate based on the old data confirmed Serrote da Laje contains 111 million inferred tonnes grading 0.55% copper and 0.16 gram gold per tonne.

Aura started drilling at Serrote da Laje one year ago, with several aims. One focus is infill drilling to upgrade the resource.

A second is to better understand the grades and distributions of iron, nickel, vanadium, and gallium, potentially valuable byproducts. Of the four, iron is particularly important — in some places, the deposit is 50% magnetite. And the third focus at Serrote da Laje is expansion drilling to the south and east, where Vale’s work was limited and a recent ground magnetometry survey identified targets.

Results from infill drilling in the northwest and central zones confirm the continuity of mineralization. Hole 184 cut 53.4 metres grading 0.74% copper, 0.14 gram gold, 22.69% iron and 0.09% nickel from 22 metres depth. A 46.7-metre intercept in hole 190 returned 0.77% copper, 0.16 gram gold, 25.28% iron and 0.1% nickel. Hole 215 hit 42.7 metres of 0.76% copper, 0.13 gram gold, 20.98% iron and 0.08% nickel from 50 metres down-hole, and hole 217 returned 0.83% copper, 0.15 gram gold, 22.27% iron and 0.09% nickel over 94 metres.

In the less-explored southern zone, drill core has returned better grades than expected. For example, hole 246 cut 45.5 metres grading 0.39% copper, 0.22 gram gold, 29.6% iron and 0.13% nickel from 69 metres down-hole and hole 254 cored 43 metres of 0.36% copper, 0.18 gram gold, 27.47% iron and 0.12% nickel.

The copper-gold mineralization is mainly disseminated, within layered norite to gabbro complexes and hosted within massive to semi-massive magnetite.

Vale’s metallurgical studies from the 1980s indicate recoveries of up to 92% for copper and 68% for gold, which went into one concentrate. A separate nickel recovery process grabbed 75% of the nickel into a second concentrate. And preliminary results showed that magnetite recovery could fairly easily produce a high-grade (over 60%) magnetite product.

Aura has baseline environmental studies under way and is actively evaluating power and transportation options. A rail line linking to three deep-sea ports crosses the property, as does a highway leading to a fourth port.

A new resource estimate for Arapiraca is due out shortly.

Aura fell 5 on the latest drill results to close at $1.68. The company has a 52-week trading range of 74-$2 and has 548 million shares issued.