Rockfire Resources plc (LON: ROCK), the Queensland copper and gold-focused resource company, is pleased to announce that it has entered into an option to acquire the Copper Dome Porphyry Copper Project in Central Queensland (“Copper Dome”), (the “Option”). Under its historical name of “Mt Leslie”, Copper Dome is listed in the “Global Mineral Resource Assessment”, published in 2010 by the US Geological Survey and, in the event the Option is exercised, would potentially add material value to Rockfire’s porphyry copper portfolio.
· Copper Dome is a large-scale mineralised system only 50km from Copperhead. The surface expression of the copper mineralisation is over 2km long and 1km wide and the prospect is vastly under-explored;
· Previous diamond drilling in 1972 intersected;
Ø 15.24m @ 0.88 % Cu (including 4.58m @ 2.28 % Cu) from 161m downhole depth
Ø 12.20m @ 0.61 % Cu (including 3.05m @ 1.24 % Cu) from 54m downhole depth
Ø 24.38m @ 0.27 % Cu (including 7.4m @ 0.43% Cu) from 225m downhole depth
Ø Percussion hole PH001 – 38m @ 0.13 % Cu (from 17m downhole depth)
· Diamond hole QML004 – 51.20m @ 0.20 g/t gold (from 72m downhole depth)
· Many intervals of visible copper mineralisation remain un-assayed for copper and gold;
· Only sporadic gold analysis has been done, with gold peaking at 1.86 g/t Au in drilling;
· The mineralisation outcrops at surface, providing low-cost, near-surface exploration, resulting in lower anticipated exploration costs.
· Should the acquisition complete, Rockfire would have 100% ownership of Copper Dome.
Chief Executive Officer of Rockfire, David Price commented:
“The acquisition of Copper Dome would be a tremendous fit with Rockfire’s existing portfolio of porphyry copper prospects and I view this as a potential strategic platform for future growth. Copper Dome provides opportunity to secure a project similar in many ways to Copperhead, with intervals of high-grade copper within a much broader envelope of copper mineralisation.”
“What I particularly like about Copper Dome is its close proximity to Copperhead and to Australia’s largest copper refinery near Bowen, approximately 250km to the north. Previous drilling and analysis indicates that mineralisation starts at surface and has been traced to at least 250m below surface. All of the previous drilling is vertical, which opens up opportunity that mineralisation hosted within vertical to sub-vertical fracture/vein networks may have been missed by previous explorers.”
“Rockfire’s work at Copper Dome will commence during the Option Period to ensure Rockfire has a better understanding of the mineralising structures and overall potential prior to exercising the Option. Our work will focus on soil sampling, ground magnetics, geological and structural mapping and an XRF survey. Owing to its proximity to Copperhead, these campaigns can be run in succession with work planned at Copperhead also.”
Copper Dome lies approximately 50 km to the southwest of Copperhead and was discovered during regional exploration for porphyry copper deposits along the east coast of Australia during the early 1970’s.
In 1972, Australian Selection Pty. Ltd. (“ASP”) drilled three percussion drill holes and six diamond drill holes, totalling 1,297 metres. All the drill holes were drilled vertically and all holes intersected geological/alteration features which the Directors of Rockfire believe could be indicative of a large-scale porphyry deposit. Best results from this drilling include 12.20m @ 0.61 % Cu (including 3.05m @ 1.24 % Cu), 15.24m @ 0.88 % Cu (including 4.58m @ 2.28 % Cu), 24.38m @ 0.27 % Cu, 12m @ 0.17 % Cu and 38m @ 0.13 % Cu.
Only sporadic gold analysis was carried out by ASP, with gold values peaking at 1.86 g/t Au. The Directors of Rockfire believe this indicates the potential for the porphyry system to contain a significant gold component.
Between 1984 and 1985, Renison Limited resampled some of the historical Australian Selection drill core for gold which returned strongly anomalous results including 51m @ 0.2g/t Au, which is very much in line with the Company’s expectations for large-scale porphyry systems.
Rock sampling by Renison focussed on faults in close proximity to historical copper workings. The best rock sampling results included 5.4 % Cu (0.41 g/t Au), 1.8 % Cu (13 g/t Au), 0.19 % Cu (2.45 g/t Au), 1.5 % Cu (0.2g/t Au) and 1.8 % Cu.
A link to Rockfire’s exploration model for Copper Dome is provided here.
The Directors of Rockfire consider the exploration potential at Copper Dome to be very high. Brecciation and faulting is common and copper/gold mineralisation has been recorded within most of the rock units. The intrusions and alteration zones span an area which is ~2km long by ~1km wide, with the dominant alteration assemblage being quartz-sericite-pyrite. The Company’s geological model adopted for this project shows a pyrite-rich phyllic shell around the edges of a typical porphyry system.
The phyllic shell hosts an average of 5% (and up to 10%) disemminated pyrite recorded in the historical geological drill logs. Localised zones of high-temperature potassic alteration are documented as chlorite-biotite alteration which is believed to be proximal to an intrusion system. The interface between the potassic and the phyllic zone is typically where the high-grade core of porphyry systems is located.
The Company believes that the Copper Dome project is attractive due to the following characteristics:
· There has not been any ground/air geophysical surveys undertaken to date
· No soil sampling has taken place
· No detailed structural/alteration/geological mapping has occurred
· There are substantial zones of visible mineralisation which have not been assayed
· The project holds potential for a missed supergene-enriched copper zone
· Vertical drilling may have missed copper/gold mineralisation hosted within vertical structures
· Rockfire’s modelling is the first evaluation using 3-D computer modelling and data analysis
· The deposit outcrops at surface, providing low-cost, near-surface exploration, resulting in lower exploration costs
Copper Dome is characterised by impressive exploration results from historical drilling, a lack of systematic, modern exploration and poorly-orientated (vertical) drill holes. Copper Dome is considered by Rockfire to be a highly prospective and under-explored prospect.
Details of the Acquisition
1. Rockfire has paid to Symbolic Resources Pty Ltd (“Symbolic”), an Australian private mineral exploration company, the Option Fee of A$20,000 (~£12,000), to keep the Option open for a period of six months from 23 November 2018, being the date the Option Agreement was signed (the “Option Period”).
2. Rockfire may then notify Symbolic at any time during the Option Period that it intends to exercise the Option, and will be then required to pay Symbolic a further A$30,000 (~£17,000) in cash and issue Symbolic fully paid new ordinary shares in Rockfire to the value of A$50,000 (~£28,000), with an issue price equal to the 5-day volume weighted average price of Rockfire shares on AIM prior to the date of issue.
At the conclusion of these two steps, Rockfire would have 100% ownership of the Copper Dome Exploration Permit to Mine (EPM26160).
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