Drilling Confirms Large Scale Gold-Copper-Silver System
These exciting drill results are the first received of three drill programs recently completed. The Rumble team is eagerly awaiting the assay results from two further drill programs, one following up two large scale Zn-Pb-Ag discoveries at the Earaheedy Project and the other following up high-grade gold intercepted at the Western Queen Project in its maiden drill program.
The Amaryllis Au-Cu-Ag Prospect lies within E51/1919 (RTR 100%), forming part of the Munarra Gully Project and lies some 60km to the north of the township of Cue, located in the Murchison Goldfields (600km NE of Perth) of Western Australia.
Historic drilling by explorers focused on gold, however, limited partial assaying by these explorers for Cu and Ag, and Rumbles Au-Cu association encountered at the White Rose prospect, highlighted the base metal potential associated with the gold at the Amaryllis Au-Cu-Ag Prospect. The mafic hosted mineralisation style detailed in historic open file exploration reports was not encountered, instead felsic to intermediate volcaniclastics with high level associated porphyritic intrusives was found in all RC drill holes completed by Rumble. Rumble's drilling successfully confirmed a large-scale Au-Cu-Ag system and identified the mineralisation style has the potential for both large-scale shear hosted Au-Cu-Ag sulphide lode type and Au-Cu-Ag-Zn VMS type deposits.
Comment by Technical Director (Brett Keillor) "The results from the inaugural RC drilling programme at Amaryllis has completely changed our original geological model as felsic to intermediate volcaniclastic/porphyritic intrusion lithologies were encountered instead of the inferred mafic intrusive lithology as reported by previous explorers. No differentiated mafics (White Rose Prospect Style) were intersected. However, the drilling confirmed broad zones of open Au-Cu-Ag mineralisation with multiple higher-grade sulphide shoots. The mineralisation is likely a modified earlier VMS system with a strong mineralising shear overprint. The drilling has highlighted the potential for two target styles - large-scale shear hosted Au-Cu-Ag sulphide deposits (intersection of mineralising shear/splay with VMS horizon) and VMS Au-Cu-Ag-Zn deposits (potentially higher in the geological profile)."
Amaryllis Au-Cu-Ag Prospect - Large Scale Gold Copper Silver System
RC drilling comprised of seventeen (17) drill holes (2809m total) focused on the main mineralised zone defined by historic drilling at the Amaryllis Au-Cu-Ag Prospect.
Significant intersections include:
- AMRC001 - 8m @ 1.13g/t Au, 0.25% Cu from 92m
- AMRC003 - 8m @ 0.88 g/t Au, 1.11% Cu, 11.8 g/t Ag from 102m
- AMRC005 - 4m @ 1.52 g/t Au, 0.96% Cu, 13 g/t Ag from 124m
4m @ 0.89 g/t Au, 0.81% Cu, 12.4 g/t Ag from 131m
- AMRC006 - 4m @ 6.21 g/t Au from 94m (composite)
- AMRC007 - 8m @ 1.94 g/t Au, 0.68% Cu, 9.5 g/t Ag from 142m
- AMRC008 - 5m @ 11.67 g/t Au from 161m
- AMRC009 - 4m @ 3.27 g/t Au, 0.46% Cu, 9.1 g/t Ag from 120m
- AMRC011 - 7m @ 1.21 g/t Au from 103m
- AMRC012 - 2m @ 13.45 g/t Au from 92m
- AMRC015 - 4m @ 3.32 g/t Au, 0.52% Cu, 8.9 g/t Ag from 100m
10m @ 2.88 g/t Au, 0.54% Cu, 7.5 g/t Ag from 146m
- AMRC016 - 2m @ 6.28 g/t Au, 0.32% Cu from 84m
10m @ 1.35 g/t Au, 0.62% Cu, 9.5g/t Ag from 108m
within 40m @ 0.89 g/t Au, 0.39% Cu, 5.7 g/t Ag from 108m
Intersections are drill length intercepts.
Drilling was conducted over a strike of 1500m with the aim to confirm gold with partial copper and silver assaying defined by historic drilling. Historic down-hole TEM from four (4) diamond core tails (also historic) with recent ground TEM completed by Rumble was also used to guide the confirmation drilling.
Geology, Alteration and Mineralisation
Wide zones of gold, copper and silver mineralisation (> 50m true width) are hosted in fine grain sericite-chlorite-quartz schist, intercalated feldspar phyric sericite chlorite schist and feldspar phyric (porphyritic) intrusives. The host rocks are interpreted to be strongly foliated felsic to intermediate volcaniclastics with multiple high level felsic to intermediate intrusives.
Alteration is pervasive throughout the felsic to intermediate rocks and is dominated by sericite - chlorite and silica. Gold, copper and silver mineralisation is associated with chalcopyrite and pyrrhotite. The overall sulphide content is generally low (up to 5%).
Multiple gold copper and silver sulphide lenses occur within the broader mineralisation haloes as steep westerly dipping "shoots" with an inferred moderate southerly plunge.
Depth of weathering is generally 80 to 100m, however, in the mineralised schist, the base of oxidation deepens to 140m. Overburden ranges from 10m at the south end of the currently defined mineralisation, to 20m cover at the north end of the currently defined mineralisation.
The Au-Cu-Ag mineralisation is interpreted to have developed at the main transition between underlying feldspar phyric felsic to intermediate high level intrusives (to the east) and overlying felsic to intermediate volcanic sediments and interflow porphyritic dacitic volcanics (to the west). Sub-parallel shearing associated with a major shear zone that lies immediately east of Amaryllis, has form a wide zone of significant epigenetic mineralisation. The source of the metal is interpreted to be earlier Au-Cu-Ag-Zn VMS mineralisation associated with the felsic volcanic rocks.
Multi-element assaying from the current drilling has highlighted zones of strongly elevated zinc in the hanging wall to the main Au-Cu-Ag zone (AMRC009 - Table 1*). Zn is also associated with the higher sulphide zones. The presence of zoned Zn with Au, Cu and Ag hosted in strongly sericitic and chloritic felsic to intermediate volcaniclastics and intrusives supports the likelihood of VMS style mineralisation as the precursor to the Amaryllis prospect.
Section 7024260N (Image 3*) presents the wide zone of intense alteration (with >1000ppm Cu +/or 0.1 g/t Au over 50m in width) within the sericite-chlorite quartz schists with intercalated feldspar phyric sericite-chlorite-quartz schists above the main felsic to intermediate intrusive package. Up to 5 zones of Au-Cu-Ag sulphide zones occur within the mineralised envelope.
Section 7023950N (Image 4*) lies 310m to the south of section 7024260N. The section highlights strong dip length continuity with the Au-Cu-Ag mineralisation.
The inaugural RC drilling programme completed by Rumble has demonstrated:
- Strong strike and dip length continuity of Au-Cu-Ag mineralisation.
- Good repeatability of Au-Cu-Ag sulphide mineralisation with respect to historic drilling results.
o The current drilling has highlighted significant higher-grade gold mineralisation compared to historic drilling. i.e. 5m @ 11.67 g/t Au and 2m @ 13.45 g/t Au.
- Au-Cu-Ag mineralisation is likely associated with a major shear zone that has overprinted earlier Au-Cu-Zn-Ag VMS (Volcanogenic Massive Sulphide) mineralisation.
- The Au-Cu-Ag mineralisation is completely open along strike and down-dip (down-plunge).
- Broad zones of Au-Cu-Ag mineralisation including:
o 40m @ 0.89 g/t Au, 0.39% Cu, 5.7 g/t Ag from 108m (AMRC016)
Potential and Targets (image 5*)
The Amaryllis Prospect (and Munarra Gully Project in general) has potential for two styles of Au-Cu-Ag-(Zn) mineralisation.
1. Orogenic Shear Related Au-Cu-Ag Deposits
- Drilling completed by Rumble at Amaryllis has demonstrated significant large-scale (width, down-dip and along strike) potential for multiple shear hosted Au-Cu-Ag sulphide lodes. The intersection of the main shear (or splay) with the inferred earlier VMS mineralised horizon has the potential to develop economic deposits, especially if the shear parallels the VMS horizon over considerable strike length.
2. VMS Au-Cu-Ag-Zn Deposits
- The Amaryllis Prospect is inferred to have developed close to the transition of intercalated felsic to intermediate volcanics and sediments and high-level feeders (porphyritic felsic to intermediate sills and dykes). The prospect likely represents a fertile VMS horizon which is also completely open along strike.
- Confirmation of inferred early Au Cu Ag Zn VMS mineralisation with whole rock litho-geochemistry and petrography
- High resolution airborne magnetics to aid in defining prospective shear and VMS horizons for next stage RC Drilling.
*To view tables and figures, please visit:
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