Rockfire Resources plc (LON: ROCK), the gold and base-metal focused explorer, is pleased to announce that drilling to test a geophysical target has returned broad, consistent gold assays, indicative of a large-scale gold deposit. Gold mineralisation occurring almost continuously throughout a 215 m deep drill hole.
· Hole BPL025 intersected 177 m @ 0.5 g/t Au, including:
· 26 m @ 1.0 g/t Au (from 22 m)
· 42 m @ 1.0 g/t Au (from 95 m)
· 7 m @ 1.0 g/t Au (from 195 m)
· The above intersection also includes zones of 1 m @ 7.5 g/t Au, 2 m @ 5.6 g/t Au and 3 m @ 6.6 g/t Au, demonstrating that high grades occur throughout this large system;
· BPL025 finished within a gold-mineralised rhyolite, which is considered by our geologists to be similar to the Mt Wright Gold Mine, (part of the Ravenswood operations hosting +10.0 M oz gold);
· Rockfire believes that BPL025 has intersected the upper levels of a large mineralised system. Resolute Mining Limited intersected the main gold lode at Mt Wright in excess of 150 m from surface. Rockfire’s technical team is anticipating gold grades to increase with depth at Plateau, as they do at Mt Wright;
· BPL025 successfully tested an IP chargeable & resistivity geophysical anomaly and proved that the target demonstrates potential for a large-scale gold system at depth;
· A geophysical survey targeting anomalies to depths of ~500 m below surface has already commenced at Plateau;
· BPL025 provides an opportunity for Rockfire to drill-out a very large gold deposit;
· The Company is eagerly awaiting the results from the remaining 13 drill holes. The market will be informed when these results are received from the laboratory.
Please refer to the following link to view the drill hole locations.
David Price, Chief Executive Officer of Rockfire, commented:
“Hole BPL025 was designed to drill down a sub-vertical pipe structure into the centre of a geophysical chargeable anomaly. This is the first indication that Plateau has grade continuity extending at depth and supports our belief that this deposit is much larger than previously demonstrated. With consistent gold, silver and zinc being encountered close to surface, we always believed that a large mineralised system was somewhere deeper down. This hole has demonstrated that mineralisation can be followed over long intervals.”
“The use of Induced Polarisation (IP) geophysics has proven to be an accurate and appropriate method of exploration at Plateau. Rockfire has commenced a geophysical survey to test for chargeable and resistive anomalies at depths approaching 500 m from surface. The aim of the geophysical survey is to identify the geometry of the gold-rich rhyolite and to target a “sweet-zone”, where higher average grades might be attainable. Rockfire believes that the discovery of the main-zone gold mineralisation still lies beneath the current drilling levels.”
“At the nearby Mt Wright Gold Mine (47 km northeast of Plateau), the 1 g/t Au mineralisation outline starts at approximately the same depths as we see at Plateau, however it is not until around 400 m from surface that the higher-grade +2 g/t Au outline starts at Mt Wright. We expect a similar gold grade increase at depth. This zone should be highlighted by the geophysical survey currently underway.”
“Rockfire is confident that geophysics will highlight any potential targets at depth and we are looking forward to seeing the responses from this survey. Once the data has been collected, processed and interpreted, we will inform the market of these results. In the meantime, the Company is also expecting assay results from the other 13 drill holes at Plateau, which were drilled as part of the same program. These additional holes were designed to extend mineralisation below previous near-surface intervals and to also test a new breccia zone (termed the Central Breccia), which was identified by our Rockfire geologists. We look forward to releasing these drilling results when received from the lab.”
Plateau October 2019 drilling collar file
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 the nearby gold mines, Mt Wright and Kidston. 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.
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 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.
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.
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