First Order Drill Targets Defined at Earaheedy Zinc Project
Six First Order Drill Targets Defined
- Detailed infill gravity surveys completed by Rumble have been modelled (gravity inversion modelling) with six first order drill targets identified.
o Importantly, the gravity targets are located over the main interpreted basement extension fault and likely represent high to moderate angle fault breccia zones with high potential to host economic base metal mineralisation.
o The gravity targets dip steeply to the southwest in line with the basement fault zone.
o The gravity targets (iso-shells) are large, up to 1.5km in strike length (EG1) and up to 300m in width
o All six gravity targets are located within the flat lying carbonate unit that hosts the known zinc-lead horizon (from historic drilling)
o Significantly, no historic drill-holes previously intercepted the six first order gravity targets to be drill tested by Rumble
Scheduled RC/Diamond Drill Program
- Two diamond tails will drill test the gravity targets EG1 and EG3 with contingency holes for gravity targets EG4 and EG6, scheduled for March 2019
- Rumble has EIS funding up to $100,750 for the drill program.
Target Potential and Style
- Review of historical drilling identified that thirty-five (35) RC and diamond drill holes intercepted zinc mineralisation over an area of 20km by 3.5km within carbonate rocks that are overlain by granular iron formations (Frere Formation). Examples of intersections:
o 11.3m @ 4.34% Zn, 0.85% Pb from 150.2m
Includes 2.3m @ 14.42% Zn, 1.15% Pb from 150.2m
o 35m @ 1.3% Zn from 208m.
Includes 6m @ 3.16% Zn from 210.5m.
o 20m @ 1.86% Zn, 0.56 % Pb from 103m to EOH.
Includes 7m @ 3.6% Zn, 1.25% Pb from 103m.
o High-grade silver mineralisation was also intercepted and includes
4m @ 559 g/t Ag from 257m (18 oz/tonne Ag)
2m @ 149 g/t Ag from 223m
No historic drill-holes have intercepted the six first order gravity targets
- Rumble is targeting Mississippi Valley Type (MVT) high-grade zinc deposits associated with basement faults (high angle breccia fault zones) within flat lying carbonate rocks
- The target size is 10-20Mt, similar to the Pillara (Blendevale) Zn-Pb deposit located in the Lennard Shelf of WA, with a strike of 2km discovered between 80m to 500m below surface for a resource of 20Mt @ 8.3% Zn, 2.5% Pb, 17ppm Ag
The area of mineralisation occurs over a strike of 20km and is up to 3.5 km in width. Rumble's Managing Director, Mr Shane Sikora, said: "In line with Rumble's strategy of generating and drill testing a pipeline of exploration projects capable of high-grade world-class discoveries, Rumble is pleased to announce an exciting development at the Earaheedy Zinc Project. As a result of Rumble's systematic drill targetting process, Rumble has identified six first order gravity drill targets at Earaheedy, with priority targets to be immediately tested with the drill-bit.
The six gravity shells are compelling drill targets that potentially represent large, mineralised zinc ore bodies. This interpretation is based on:
- the widespread Zn and Pb metal distribution surrounding the gravity targets;
- the gravity shells highlighting dense areas which could represent mineralisation accumulation;
- a review showing that no historic drilling intersected the targets;
- the targets are positioned at the same depth of zinc mineralisation identified in historic drilling;
- the targets are located over the main interpreted basement extension fault; and
- Importantly, modelling determined the dip of gravity targets are in line with the basement fault which could reflect mineralisation intrusion.
These elements combined, and the large size of the gravity targets (up to 1.5km in strike length and up to 300m in width), provide the potential to host a target of 10-20mt Mississippi Valley Type (MVT) type high-grade zinc deposits, Rumble looks forward to drill testing these targets and providing shareholders with a near term opportunity for a significant re-rating that would be expected as a result of any exploration success."
Rumble has an option agreement with Fossil Prospecting Pty Ltd (a wholly owned subsidiary of ASX Listed Zenith Minerals Ltd - (ASX: ZNC) to acquire a 75% interest in E69/3464. Rumble owns 100% of the contiguous application E69/3543. The Earaheedy Project is located approximately 110km north of Wiluna, Western Australia. Zinc and lead mineralisation with elevated silver is associated with the Navajoh Dolomite Member (also known as the Sweetwaters Well Member) of the Yelma Formation. The Yelma Formation is the lower unit of the 5000m thick Earaheedy Basin (Palaeoproterozoic). Sphalerite, galena, pyrite and marcasite (coarse grain) occurs as stratiform/stratabound ore fill veins and breccias, dissolution cavity fill, disseminated, stylolitic and fault fill mineralisation styles (Mississippi Valley Type). Broad spaced drilling (completed in the 1990's) defined oxidised and primary Zn-Pb mineralisation (zinc dominant) over a strike of 20km.
The mineralisation is associated with a flat lying to shallow northeast dipping laterally continuous dolomite to shale horizon. The initial drill spacing was 5 to 10km. The current drill program spacing is approximately 2km by 1km.
Review of the historic drilling has concluded that approximately half the drill holes did not intercept the target horizon.
A total of 64 drill holes were previously completed within the project area (E69/3464), with 35 drill holes intercepting the stratiform zinc horizon (including partial end of hole intercepts).
Mineralisation has been defined over an area of approximately 20km by up to 3.5km in width and is completely open.
Significant Zn and Pb intercepts include:
- TDH4 - 11.3m @ 4.34% Zn, 0.85% Pb from 150.2m including 2.3m @ 14.42% Zn, 1.15% Pb from 150.2m
- TDH28 - 55m @ 0.87% Zn from 323m including 11m @ 1.2% Zn from 325m and 5m @ 2.32% Zn from 354m
- TDH14 - 31m @ 1% Zn from 222.5m including 10.4m @ 3.28% Zn from 225m
- TRC70 - 5m @ 2.52% Zn from 126m to EOH
- TRC47 - 20m @ 1.86% Zn from 103m to EOH
- TRC49 - 6m @ 1.36% Zn from 112m to EOH
- NRC09 - 4m @ 1.7% Zn from 127m to EOH
Significant silver (Ag) mineralisation intercepts include:
- TDH16 - 4m @ 559 g/t Ag (18oz/tonne) from 257m and 2m @ 149 g/t Ag from 223m
Gravity Survey and Targets (Figures 3, 4 and 5)
Two surveys covering an area of 24km2 were completed on 100m by 100m and 200m by 100m spacings (1080 stations). The surveys targeted the main basement fault zone (interpreted from aero-magnetics) and the stronger base metal drill-hole intercepts from the historic drilling. Gravity inversion modelling has defined six (6) first order targets that occur over the main basement fault structure (Figure 3.). The targets are determined by variations in density contrasts (iso-shells). Targets EG1 to EG6 (see figures 3 & 5) are defined by the 0-200 (0.20 g/cm³) iso-shell.
- The six gravity targets sit below the overlying Frere Iron Formation and their dip length strongly correlates with width of the carbonate formations that host the historic Zn mineralisation (see figure 4).
- The steep dip of the gravity targets (steep southwest) also reflect the inferred dip of the underlying basement fault.
- The depth of the gravity targets gradually deepen to the southeast in line with the basement fault and dip of the hosting sediments.
- The gravity targets (EG1 to EG6) are interpreted to be associated with high angle fault/fault breccias that extend from the basement and are hosted in the main carbonate units.
- The targets represent bodies defined by density contrasts and these bodies may reflect denser carbonate rich zones or more significantly (based on the widespread Zn and Pb metal distribution), base metal mineralisation (epigenetic replacement).
- The gravity targets (iso-shells) are up to 1.5km in strike length (EG1) and up to 300m in width.
- Review of the historic drilling has indicated no drill hole has intercepted any of the gravity targets.
- Historic drill holes that are close to the gravity targets include TDH19 (approximately 250m into the hanging wall of target EG1 - see figure 4) which returned a wide low-grade intercept of 56m @ 0.46% Zn from 209m.
Target Potential and Style
The target style for the Earaheedy Zn project is considered Mississippi Valley Type (MVT) with economic sphalerite - galena mineralisation hosted in high to moderate angle fault/fault breccia.
Widespread flat lying carbonate replacement by low grade Zn and Pb sulphides has been delineated by historic drilling at Earaheedy. The area of flat lying mineralisation is very significant (20km by 3.5km) indicating extensive metal input and is completely open along strike and down dip. The historic drilling is wide spaced and has not tested the zone within the carbonates overlying the main basement fault.
Previous work by Rumble has highlighted strong metal zonation Zn:Pb ratios paralleling the basement fault (refer to ASX Announcement 12/10/2017 - Option Agreement to acquire Earaheedy Zinc Project). Metal zonation is characteristic of MVT deposits in the Devonian Lennard Shelf of Western Australia and has proven to be a useful vector to aid in delineating high-grade faults mineralisation.
The target size is considered to be 10-20Mt, similar to the Pillara (Blendevale) Zn-Pb deposit located in the Lennard Shelf of Western Australia. The Pillara deposit occurred over a strike of 2 km and was located 80 to 500m below surface. The geological resource was 20Mt @ 8.3% Zn, 2.5% Pb, 17ppm Ag. The deposit produced 10.3Mt @ 6.9% Zn and 2.3% Pb. Of note, the discovery drill-hole (8m @ 8.9% Zn, 3.5% Pb below 210m).
Proposed Diamond Drilling
Rumble has scheduled a drilling program to test the significant first order drill targets in March 2019.
Two diamond tails will drill gravity targets EG1 and EG3 with contingency holes for gravity targets EG4 and EG6. The expectation is for 100m pre-collars with diamond tails up to 300m.
Figure 4 highlights the proposed diamond drill hole into target EG1.
Rumble has received EIS (co-funding) funding approval ($100,750) for this diamond drilling program.
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About Rumble Resources Ltd
Rumble Resources Limited (ASX:RTR) (FRA:20Z) is an Australian based exploration company, officially admitted to the ASX on the 1st July 2011. Rumble was established with the aim of adding significant value to its current gold and base metal assets and will continue to look at mineral acquisition opportunities both in Australia and abroad.
Rumble Resources Ltd