Rockfire reports 'strongly magnetic' drill targets at Copper Dome

Gold and base metal exploration company Rockfire Resources announced results from 3D processing of helicopter magnetic data at its wholly-owned Copper Dome porphyry project in north Queensland, Australia on Wednesday.

The AIM-traded firm said the original survey was flown in April, with the newly processed data highlighting “strongly magnetic” drilling targets at depth.

It said two main targets had been highlighted, with both showing “very strong” magnetic responses, which were being interpreted as magnetite alteration - an important feature associated with many porphyry copper deposits.

The targets start about 500 metres below surface, with the larger target 1.5 kilometres long, 700 metres wide and occurring between 400 metres and 1.3 kilometres deep, remaining open beyond that depth.

Rockfire said the smaller target was 900 metres long, 250 metres wide and occured between 600 metres and at least one kilometre deep.

Historical diamond drilling from 1972, directly above the targets, intersected typical porphyry grades including 88 metres at 0.23% copper and 75 metres at 0.13% copper, with most holes ending in copper mineralisation.

Peak values from core sampling were 3.77% copper and 1.8 grams of gold per tonne.

Alteration identified in core was primarily sericite-pyrite phyllic alteration, suggesting that the current surface was at the upper-mid levels of a copper-gold porphyry system.

Sulphides in core ranged from 3% to 15% pyrite, with associated chalcopyrite, and fluids were recorded in geological logs as being focussed within porphyritic intrusions and breccias.

Rockfire said it was preparing for drilling initially at the Copperhead porphyry copper project, and intended to drill the new magnetic anomalies at Copper Dome during the field season as well.

“This 3D modelling has produced images of two very high-intensity magnetic responses beneath the dome,” said chief executive officer David Price.

“Both targets deepen towards the south, suggesting that the source may lie to the south.

“The closest they come to the surface is around 500 metres depth, but historical drilling has hit copper much closer to the surface.”

Price said that after nearly 50 years with no significant exploration at Copper Dome, Rockfire was planning to drill the new targets.

“With confirmed copper and gold close to the surface directly above the targets and well-defined high magnetic targets at depth, these factors bode well for discovery.

“Rockfire is preparing for drilling at Copperhead initially and drilling at Copper Dome is also planned.

“The company will provide the market with regular updates on our progress as we work towards the start of drilling at our porphyry projects.”

At the close, shares in Rockfire Resources were down 5% at 0.95p.