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Rockfire Resources - Geochemical study strengthens Mt Wright analogy

RNS Number : 6631I
Rockfire Resources PLC
03 April 2020

3 April 2020

Rockfire Resources plc

("Rockfire" or the "Company")

Geochemical study strengthens Mt Wright analogy

Rockfire Resources plc (AIM: ROCK), the gold and base-metal explorer, has completed further technical interpretation on the Company's 100%-owned Plateau Gold Deposit ("Plateau"), part of the Lighthouse tenement in North Queensland, Australia.

With the Plateau Gold Deposit site currently under the influence of the wet season as expected, technical data analysis and comparison studies between Plateau and the nearby Mt Wright Gold Mine, 47km to the northeast of Plateau, are on-going. Results from this work continue to demonstrate that a significant deposit of gold has been intersected at Plateau.

Gregg Morrison of Klondike Exploration Services, the pre-eminent expert in North Queensland geology has analysed the results of the Company's recent work and is assisting Rockfire's geology team. Mr Morrison developed the multi-element geochemistry classification and zoning model which was used to characterise the Mt Wright Gold Mine and he has observed many similarities between Plateau and the early observations at Mt Wright, as detailed below.

·    Broad gold zones (0.2 g/t Au to 0.5 g/t Au) in the top 200m from surface

·    Broad lead/zinc/silver (Pb-Zn-Ag) anomalous halo

·    Mineralisation is between 60 m and 80 m thick at both deposits

·    Similar patterns evident from plotting geochemical ratio "z-scores"

·    Breccia and rhyolite are the two main host rock types

·    Both deposits are approximately 200 m - 250 m long

·    Multiple rhyolite emplacement and multiple mineralising phases

·    Alteration by sericite-pyrite-marcasite, with minor quartz-carbonate-sphalerite

·    Multielement geochemical zonation is expected to assist high grade gold targeting at depth

·    Similar resistivity and magnetic geophysical responses

A new long section showing mineralisation at Plateau can be viewed via the link below. This section shows the consistent and predictable nature of gold and silver mineralisation at Plateau. A target of higher-grade gold is anticipated at depth, based on the Mt Wright Gold Mine, which has had over 1.5 million ounces of gold mined. Importantly, the main gold zone at Mt Wright was discovered beneath a 250 m zone of broad gold averaging between 0.2 g/t Au and 0.5 g/t Au, similar to that being encountered at Plateau.




David Price, Chief Executive Officer of Rockfire, commented:

"As we had planned for limited access to site during the wet season in North Queensland, the Company has continued to make progress with other, non-field-based activities; notably analysing the similarities between our Plateau Project and the Mt Wright Gold Mine."


"The similarities continue to far outweigh the differences and we are extremely fortunate to be able to access Gregg's experience and knowledge. It is exciting when someone with such intimate knowledge of Mt Wright is observing comparisons with Plateau; the elevated gold, silver and zinc encountered by Rockfire over hundreds of metres of drilling was also evident in the upper levels of Mt Wright prior to the discovery of the main gold zone.


"The multi-element model being developed for Plateau by Gregg and our Exploration Manager, is leading to some very exciting drill targets being defined. Management is looking forward to drilling again at Plateau as soon as practicable."


Qualified Person Statement: 

Information in this announcement that relates to exploration results is based on information compiled by Mr Edward Fry, the Exploration Manager of Rockfire Resources plc, who is a Member of the Australasian Institute of Mining and Metallurgy (MAusIMM). Mr Fry has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which has been undertaken to qualify as a Competent Person as defined by the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC Code) and a "Qualified Person" in accordance with the AIM Rules Guidance Note for Mining and Oil & Gas Companies. Mr Fry consents to the inclusion in the announcement of the matters based on their information in the form and context in which it appears.


For further information on the Company, please visit www.rockfireresources.com or contact the following:


Rockfire Resources plc:

[email protected]

David Price, Chief Executive Officer




Allenby Capital Limited (Nominated Adviser & Broker)

Tel: +44 (0) 20 3328 5656

John Depasquale / Asha Chotai




Yellow Jersey

[email protected]

Sarah Hollins / Henry Wilkinson / Emma Becirovic

Tel: +44 (0) 20 3004 9512



About the Plateau Gold Deposit


The Plateau Gold Deposit is located in Queensland Australia, approximately 50 km southeast from the gold mining centre of Charters Towers. Plateau lies 17 km east of the operating Pajingo Gold Mine (+ 3 M oz Au), and 47 km southwest of the +10 M oz Au Ravenswood gold mining operations, including Mt Wright. Plateau is a breccia-hosted gold system, comprising similar geology and mineralisation to that seen at Mt Wright. Rockfire is targeting another Mt Wright-style and size of deposit.

At surface, Plateau hosts gossanous and jasperlitic veins and gold-bearing breccia at the margin of a felsic (rhyolite) plug. The deposit is under-explored but historical drilling has returned intervals of high-grade gold from a distinct circular magnetic feature. This feature is partly demagnetised and truncated by a linear northeast fault with associated polymict breccia, gossan and chalcedonic and jasperoidal silica flooding.

Previous drilling campaigns have intersected encouraging drilling intersections including 89 m @ 1.57 g/t Au from 61 m (hole PL102), 11 m @ 2.0 g/t Au from 44 m (hole PLP127) and 22 m @ 1.9 g/t Au from 39 m (BPL002).

A single, deep diamond hole drilled by Newcrest Mining in 2007 intersected 300 m @ 2.2 g/t Ag (hole PLDD06001), which highlights the potential size of the mineralised system at depth. This hole provides clear evidence that a large mineralised gold +/-silver system exists deeper below current drilling levels.

In October 2019, Rockfire drilled a 217 m deep reverse circulation hole which intersected 177 m @ 0.5 g/t Au. Drilling in January 2020, the results of which are included in this RNS was successful in extending the outline of what is believed to be a very large gold mineralised system.


Plateau Exploration History

In 1985, Esso Australia Ltd drilled 876 m of core drilling (in 3 holes), 350 m of percussion drilling (in 4 holes) and 126 m of pre-collar drilling for a total of 1,352 m. Impressive drilling results were encountered close to surface, including: 3 m @ 4.87 g/t Au, 3 m @ 3.38 g/t Au, 89 m @ 1.57 g/t Au, 5 m @ 2.77 g/t Au, and 40 m @ 1.37 g/t Au. A total of 1,260 m of trenching was undertaken during the 1985 field season with results including 40 m @ 1.37 g/t Au (Trench 3700 E). Esso also sampled the surface rocks at Plateau, which returned a 116 g/t Au assay.

In 1988, City Resources Ltd drilled 30 reverse circulation drill holes for 1,670 m at Plateau. Values up to 16 g/t Au were intersected in drilling which tested gold mineralisation down to 60 m vertical depth. Best results from this drilling include: 8 m @ 3.03 g/t Au, 10 m @ 5.01 g/t Au, 14 m @ 2.44 g/t Au, 6 m @ 3.20 g/t Au, and 4 m @ 4.79 g/t Au.

In 2007, Newcrest Mining Limited drilled a single 853.7 m deep diamond drill hole (PLDD06001). This hole was designed to test mineralization at depth beneath the shallow mineralisation at Plateau. PLDD06001 intersected 300 m @ 2.2 g/t Ag but only low-grade gold. The drill hole intersected breccia between 150 m and 520 m below surface, confirming that the breccia is much larger than the surface expression suggests. This hole is now thought to have intersected the very edge of the projected mineralised lode, but likely too far to the west to encounter significant gold. A second hole was planned by Newcrest further to the east but this hole was never drilled.

In late 2017, Rockfire Resources plc drilled 11 drill holes (BPL001 to BPL011) for 2,111 m of reverse circulation drilling. This drilling successfully encountered 10 m @ 1.9 g/t Au, 22 m @ 1.86 g/t Au and 10 m @ 1.37 g/t Au. Significant silver was also encountered including 43 m @ 4 g/t Ag.

In October 2019, Rockfire Resources plc drilled a further 14 drill holes (BPL012 to BPL025). This drilling encountered 177 m @ 0.5 g/t Au and 187 m @ 6.3 g/t Ag. This was the first drill program to encounter such broad zones of gold and silver mineralisation. Extension drilling at East Plateau intersected 30 m @ 1.2 g/t Au, 22 m @ 1.0 g/t Au, 5 m @ 4.8 g/t Au and 4 m @ 4.2 g/t Au. Drilling at a newly discovered "Central Breccia Zone" returned grades of 6 m @ 4.1 g/t Au, 12 m @ 1.2 g/t Au, 7 m @ 2.3 g/t Au and 5 m @ 1.3 g/t Au.

A third round of drilling in January 2020 by Rockfire Resources plc (BPL026 - BPL031) encountered significant, broad intervals of gold in multiple drill holes. Results included 171 m @ 0.4 g/t Au (from 26 m), including 39 m @ 1.0 g/t Au, 170 m @ 0.4 g/t Au (from 37 m) including 19 m @ 1.0 g/t Au and 154 m @ 0.2 g/t Au (from 97 m), including 46 m @ 0.3 g/t Au.

This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact [email protected] or visit www.rns.com.

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