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Rockfire Resources (ROCK)

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Monday 10 June, 2019

Rockfire Resources

Copperhead upgraded to 122,500t copper equivalent

RNS Number : 7084B
Rockfire Resources PLC
10 June 2019

This announcement contains inside information as stipulated under the Market Abuse Regulations (EU) no. 596/2014 ("MAR").

10 June 2019

Rockfire Resources plc

("ROCK", "Rockfire" or "the Company")

Copperhead upgraded to 122,500t copper equivalent

Further to its announcement on 2 July 2018, Rockfire Resources plc (LON: ROCK) is pleased to announce a grade increase to the 1972 historical metal estimate at its 100% owned Copperhead Project in north Queensland, Australia ("Copperhead"). This upgrade results from including a second round of core sampling in 1988 and significant molybdenum, both of which were not included in the original estimate.

·      The inclusion of molybdenum significantly increases Copperhead's average copper equivalent (Cu Eq.) grade to 0.35%, from 0.25% as established by drilling in 1988; 

·      Using the original tonnage and the new Cu Eq. grade of 0.35%, the amount of in-situ copper increases from 56,000 tonnes of copper to 122,500 tonnes of copper equivalent value;


·      At a current copper price of £4,535 per tonne, this represents an in-ground value of £555m*;


·      Rockfire has developed a staged exploration target, with planned drilling expected to deliver the next milestone of between 50 - 100 million tonnes, with a grade range of 0.30 - 0.40% Cu equivalent**;


·      The estimated tonnage only includes a small drilled portion (approximately 5%) of a large surface geochemical anomaly which is 3km x 2km in area and mineralisation remains open in all directions 


·      All historical drill holes (5 in total) were mineralised with copper and molybdenum throughout their lengths and terminated in mineralisation;


·      Copperhead is 100% owned by Rockfire Resources plc;



David Price, Chief Executive Officer of Rockfire commented

"Our technical team have been working on the Copperhead Project to plan geophysical surveys. During this detailed planning, it was noted that the original drilling encountered significantly high values of molybdenum. When the molybdenum values are incorporated into the original 1972 estimate, the result is a much higher average copper equivalent grade. Additionally, the copper values obtained from subsequent sampling of the drill core in 1988 further increase the average grade to 0.35% Cu equivalent."


"This is a very significant finding for the Company. It is worth noting that the average grade of all copper produced from the USA, Canada, and Mexico between 2005 and 2017 varies between 0.25 - 0.40 % copper."


"We are very excited by Copperhead's potential and have developed a staged and thorough exploration approach. Planned drilling is expected to deliver the next important growth milestone. In the interim, geophysical surveys are being designed to highlight potential zones of higher copper grade. Success with such a program could materially enhance the economic potential of the project."



* In-ground values do not account for capital and operating costs, economic factors or mining methodologies; LME copper price of USD $5769 and an exchange rate of 1 USD to 0.79 GBP, dated 10 June 2019.

** This is an exploration target only and must not be misconstrued as an estimate of a Mineral Resource or Ore Reserve. The potential quantity and grade are conceptual in nature. There has been insufficient exploration to estimate a Mineral Resource and it is uncertain if further exploration will result in the estimation of a Mineral Resource.


About Copperhead


Five diamond drill holes were completed at Copperhead in 1972 by Carpentaria Exploration Company Limited. Each hole recorded visible chalcopyrite, molybdenite, pyrite and occasional bornite throughout their lengths, with two of these holes being 300m long. The geology and assay results indicate a potentially large copper, molybdenum and silver mineralised system.


According to Carpentaria Exploration Company Pty Ltd, Copperhead has a mineral content estimate which is based on these 5 drill holes. This historical estimate was calculated prior to the introduction of the JORC Code and was an internal estimate calculated by Carpentaria Exploration based on standard exploration drilling and analysis techniques at the time. The amount of mineral content quoted is 35Mt @ 0.16% Cu, for a total of 56,000 tonnes of copper metal. The USGS "Global Mineral Resource Assessment" and the Queensland Geological Survey quote the mineral content estimate as defined by the 1972 Carpentaria drilling.


Based on bulk averages of core sampling, Carpentaria completed an internal polygonal mineral estimate. The following parameters were used in the estimation:


•           Surface extent was delineated by a 500ppm copper-in-soil outline

•           A Specific Gravity (S.G.) of 3.0

•           A pit slope (batter angle) of 60°

•           A final pit depth of 300m


This initial estimate only includes a small drilled portion (approximately 5%) of a large surface geochemical anomaly which is 3km x 2km in area and mineralisation remains open in all directions. The grades reported by Carpentaria in its core sampling don't account for shears or fault zones, which could potentially enhance the overall grade of the system and which Rockfire believe to be present.


In 1988, Costain Australia located the original core drilled by Carpentaria and assayed additional sections of the core which were not previously analysed. This second phase (in-fill) core analysis returned grades up to a peak value of 2.81% Cu and 1.54% Mo. This latter sampling increased the weighted average grade of all core sampled to 0.25% Cu.


Subsequent modelling work by Rockfire includes both the original and follow-up copper sampling of the core, as well as the molybdenum values from both programs. Rockfire has used an Inverse Distance Weighting (IDW) block model to determine tonnages and average grade for each block. This technique results in an average IDW grade of 0.35% Cu Eq. The 16th May 2019 London Metals Exchange USD copper and molybdenum prices of $6001 & $27116 were used respectively to calculate each individual sample's copper equivalent. A top cut of 7000 ppm copper and 1200 ppm Mo was applied to remove the influence of outliers. The independent copper and molybdenum average grades are 0.21% and 0.03% respectively. 


Qualified Person Statement:

Information in this announcement that relates to historical exploration results is based on information compiled by Mr Edward Fry, an Officer of Rockfire Resources plc, who is a Member of the Australasian Institute of Mining and Metallurgy (AusIMM). 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 under the AIM Rules - 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.

In quoting exploration targets, the potential quantity and grade is conceptual in nature. There has been insufficient exploration to estimate a Mineral Resource and it is uncertain if further exploration will result in the estimation of a Mineral Resource.


For further information on the Company, please visit or contact the following: 

Rockfire Resources plc

Email: [email protected]

David Price, Chief Executive Officer




Allenby Capital Limited (Nominated Adviser)

Tel: +44 (0) 20 33 285 656

John Depasquale/ Asha Chotai




First Equity Limited (Joint Broker)

Tel: +44 (0) 20 73 742 212

Jason Robertson




SI Capital (Joint Broker)

Tel: +44 (0) 1 483 413 500

Nick Emerson




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