Rockfire Resources plc
(“Rockfire” or “the Company”)
56,000T copper in Copperhead historical estimate
The Board of Rockfire Resources (LON: ROCK), is pleased to inform shareholders that a recent review of previous work at Copperhead has revealed an historical estimate of metal content of 56,000T copper at its 100%-owned Copperhead Project in north Queensland, Australia.
- A detailed appraisal of past exploration at Copperhead has unveiled an estimate of copper content calculated by Carpentaria Exploration Company Pty Ltd (“Carpentaria Exploration”) in 1972.
- 35 million tonnes @ 0.16% Cu for 56,000t of copper **. Note that 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. Subsequent core sampling in 1988 has lifted the average core grade to 0.25% Cu.
- The monetary equivalent of an “in-ground” value** can be calculated as an exploration target only, using open sources such as the current price of copper on the London Metal Exchange (US$6,711/t as at 28th June 2018). Any calculation of In-ground values do not take into account capital and operating costs, economic factors or mining methodologies.
- Induced Polarisation geophysics is being planned to help target potential extensions and high-grade zones
- Drilling is being planned to verify and expand the historical drilling results to enable Rockfire to establish a mineral resource at Copperhead in due course
|** The estimation provided is historical in nature and not reported in accordance with the JORC Code. A competent person has not done sufficient work to classify the historical estimates as mineral resources or reserves in accordance with the JORC Code. The potential in-ground value, as well as the historical 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.
Chief Executive Officer of Papua Mining, David Price commented:
“It is exciting to have an historical mineral estimate by such a reputable company as Carpentaria Exploration. Bear in mind that many world-class gold and copper deposits were discovered in the 1970’s – before the dawn of the JORC Code. The inclusion of Copperhead in the United States Geological Survey’s “Global Mineral Resource Assessment” is testimony to the project’s potential. The estimation of this historical mineral content provides a great baseline minimum target from which the project can expand.”
As part of the Company’s annual technical reporting to the Queensland Department of Natural Resources and Energy, a thorough review of past exploration reports, analysis of exploration data and digitisation of the historical results at Copperhead has recently been completed. Copperhead is an under-explored copper deposit in Queensland with the potential to become a large-scale porphyry copper project.
Under its historical name of “Julivon Creek”, Copperhead is included in the Global Mineral Resource Assessment by the United States Geological Society (USGS) in its “Porphyry Copper Assessment of Eastern Australia” Technical Paper dated 2014. This report was prepared to highlight the most important porphyry copper deposits known to exist on the eastern seabord of Australia.
Five diamond drill holes were drilled at Copperhead in 1972 by Carpentaria Exploration Company Limited. Each hole recorded visible pyrite, +/- chalcopyrite 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 Report Number CR-4538 by Carpentaria Exploration Company Pty Ltd dated December 1972, Copperhead has a pre-JORC mineral content estimate which is based on these 5 drill holes. 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” also quotes the mineral content estimate as defined by the 1972 Carpentaria drilling.
Based upon 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 estimate only includes a small drilled portion of a large surface geochemical anomaly and mineralisation remains open in all directions.
The grades achieved by Carpentaria in its core sampling don’t take into account any shears or fault zones which could enhance the overall grade of the system. In 1988, Costain Australia located the original core drilled by Carpentaria and assayed portions of the core not previously analysed. This second phase (in-fill) core analysis returned grades up to peak values of 2.81% Cu and 1.54% Mo. This subsequent sampling, lifted the overall grade to achieve an average core sampling grade of 0.25% Cu.
Based on a combination of soil, rock, auger and diamond drilling (with a an average of all core assays being 0.25% Cu), the Company believes that Copperhead presents an initial exploration target *** of 60MT – 75MT, at grades of between 0.15% Cu and 0.20% Cu, and with material silver and molybdenum credits. This exploration target is for the potential delineation of 90,000 – 150,000 tonnes of copper metal.
|*** 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 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.|
What to expect next:
A gradient array geophysical survey is being planned to determine if chargeable or resistive responses are present close to surface.
If a potential target is identified, a series of dipole-dipole IP lines will follow to test for anomalous responses at depth. A ground magnetic survey will also be completed in order to highlight faults, offsets and geological disconformities.
Should suitable anomalies be discovered, a reconnaissance drilling program will follow to systematically test the top 100m from surface over the area covered by historical drilling. Additionally, some deeper drilling may follow to intersect any geophysical targets identified at depth.
Competent Person Statement:
Information in this announcement that relates to exploration results is based on information compiled by Mr David Price, a Director of Rockfire Resources plc, who is a Fellow of the Australasian Institute of Mining and Metallurgy (FAusIMM). Mr Price 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 Price 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 www.rockfireresources.com or contact the following:
|Rockfire Resources plc
David Price, Chief Executive Officer
Cenkos Securities plc
Nominated Adviser & Broker,
Derrick Lee/Beth McKiernan
+44 131 220 6939