Rocky River-Uralla Goldfield

The Sovereign / SUGEC JV Project Tenements are centred on the town of Uralla, and are located 21 kilometres southwest of Armidale in the New England district of New South Wales. The area is extremely well supported by existing infrastructure, road, rail, power and engineering.

Key Highlights

  • Confirmed discovery of a large IRGS
  • A$11 million work program underway at Rocky River Uralla Goldfield, fully funded by investment from Chinese SOE JV partner Jiangsu Geological & Engineering Co Ltd (SUGEC)
  • Striking similarities to the giant Donlin Creek IRGS gold deposit in Alaska
  • Collaboration between Senior Geoscientists from the NSW Geological Survey and Sovereign Gold to potentially invigorate gold exploration in the New England Fold Belt and lead to world class discoveries
  • Superb infrastructure logistics for operating environment: close to major sealed roads, rail, airport, labour source, University, water, power, engineering, foundries and other key services
  • Positive landowner relationships throughout Uralla-Armidale-Guyra districts.
  • Open access to predominately grazing country for fine wool and cattle.
  • High environmental standards using low impact equipment coupled with continuous rehabilitation exploration methods.


Rocky River-Uralla Goldfield – Historic gold mine
The Rocky River – Uralla Goldfield was discovered in 1852 and has a recorded production of 167,000 oz gold (noting the actual figures could be twice the recorded amount). There is potential that several tonnes of gold remains in the current alluvial system. IRGS deposits have liberated up to 15 tonnes of gold to river deposits. This IRGS has striking similarities to the giant Donlin Creek IRGS deposit, with gold in dykes like Martins Shaft, of the Yukon-Alaska running Tintina Gold Province.

Sovereign Gold has determined that many of the historic gold mines are closely associated with minor intrusions and felsic dykes. This association indicates an IRGS may be present. The recognition of an IRGS, is important because it means there is potential for the gold deposits to be much larger than that indicated by exposure of mineralisation in old workings.

Historically, most of the gold from the Rocky River-Uralla Goldfield was produced from Tertiary deep leads. In earlier times, however, not a lot of work was done to find the source of the gold. Gold that was won from hard rock mines was assumed to represent a series of small isolated Orogenic Gold Deposits, rather than an inter-related system. Today it is recognized that the Rocky River-Uralla Gold Field has the hallmarks of what is now known as an IRGS.

Diagnostic characteristics similar to Donlin Creek
Martin Shaft has classic IRGS mineralisation diagnostic characteristics:

Comparison of the Rocky River IRGS Model with General plan model

Many of the mines plot on or are near a major magnetic linear feature that coincides with the Old Bonanza Dyke. This feature is continuous over several kilometres and strikes northeast. Other mines plot on a slightly different northerly trend that intersects the northeast trending magnetic feature. The magnetic features are suggestive of strong structural controls that are of particular interest wherever they intersect.

Magnetic image overlayed on geology with Historical Exploration and Mine Areas

Martins Shaft: Significant gold discovery
A significant discovery has already taken place at Martins Shaft, demonstrating Proof of Concept.  Drill intercepts include 22m @ 3.2 g/t Au, including 1m @ 22.5 g/t Au, and widening and open at depth, deepest hole 110m vertically.

Results include:
SGRDD002    22m @ 3.2 g/t Au (incl. 10m @ 6.1g/t Au, incl. 2m @ 18.9g/t Au)
SGRDD004    18m @ 3.5g/t Au (incl. 7m @ 7.5g/t Au, incl. 1m @ 19.6g/t Au)
SGRRC006    9m @ 2.9 g/t Au


Martins Shaft, drill intercepts and 3-dimensional wireframe model of mineralised lode – widening with depth

Beneficial SUGEC JV
Joint Venture with Chinese SOE SUGEC from on Nanjing, China, in ELs 7768 and 7491 with SUGEC contributing A$4 million to exploration before 31 March 2014, at which time Jiangsu may earn a 30% interest in each tenement.

SUGEC IRGS Joint Venture – Fully funded program & Rapidly Expanding Discovery Progressing

 

  • Multiple dyke swarms mapped cut by north-east trending mineralised structures
  • Fully funded 2,500m drilling program continues – mineralisation deepening and widening
  • 1.55km Mineralised Structure – Hole ZK0001 completed (113.7m) under SGRDD036
    • Gold-bearing mineralisation and alteration over 21m from 77m – 98m including
      • 0.9 g/t Au over 2m from 79.5–81.5m
      • 1.1 g/t Au over 8m from 90.0–98.0m including
        • 3.95 g/t Au over 0.5m from 93.0–93.5m
  • SGRDD036 intersected 2.72g/t Au over 5m from 7-12 metres downhole including
    • 7.8g/t Au over 1m and 12.35g/t Au over 0.5m
  • ZK0003 intercepts mineralised zone from 101.0–106.7 meters deep, mineralisation continues
  • High precision GPS (using Continuously Operating Reference Station – CORS signal) geological mapping at 1:2000 scale for detailed comparison with Donlin Creek analogue underway
  • Fully funded by Joint Venture partner, SUGEC, funding $2m exploration program on EL7491 to March 2014
  • Testing large scale Intrusion-Related Gold Systems (IRGS)
  • Deep drilling designed to assess full potential of 1.55km long identified gold-bearing structure
  • The campaign is expected to be completed in the September quarter– regular updates will be provided to the market
  • Dual drill rigs operating simultaneously

Diamond Drilling EL 6483 and EL 7491
EL 6483 is contiguous to EL 7491 – the large Intrusion-Related Gold System (IRGS) of the Rocky-River Uralla Goldfield extends across both ELs.
Following detailed geological mapping and geochemical and geophysical surveys a series of close-spaced northeast dominant mineralised structures and subsidiary semi-orthogonal structures that cut north-west trending felsic dykes have been discovered. One of the mineralised shear zones has been traced for 1.55km and is the current focus of drilling. Martins Shaft-style mineralisation has been intersected in the felsic dykes. Drilling has revealed brecciation and silica-sulphide flooding accompanied by tongues of mineralised felsic dykes in mineralised metasediments along the 1.55km long structure. This extensive mineralised shear zone-fault system may represent a high level fracture fluid plumbing system developed above a potential IRGS Hobbs-style pipe.

Conceptual Target. 1.55km long northeast trending shear structure (main fault zone shown in blue) surrounded by altered fractured zone (green). The main fault structure is associated with and cut by oblique faults. Geochemical and rock chip mapping has located nearby (within 500m) parallel alteration structures with similar mineralisation. The structures are flooded with quartz-sulphides and ‘tongues’ of felsic dykes that may be derived from a small pipe-like pluton at depth. The current target being drilled and the parallel and oblique structures occur from surface and have potential for an open-cut gold resource.


 

  Northeast trending 1.55km long gold-bearing structure

 

Sovereign Gold previously drilled seven shallow holes along this structure. The holes have shown both high grade (up to 12.35g/t Au) and wide (12 metres downhole) gold mineralisation at shallow depths potentially suitable for open-cut. Results included 2.72g/t Au over 5m from 7-12m downhole including 7.8g/t Au over 1m and 12.35g/t Au over 0.5m in diamond drill hole SGRDD036 and 1.07g/t Au over 12m from 3-15m downhole including 4.93g/t over 0.6m in SGRDD037. This gold mineralisation occurs within the same large felsic dyke system hosting Martins Shaft. The SUGEC supplied drill rig completed diamond drill hole ZK0001 to a depth of 113.7m and is well underway with second hole ZK003 that has encountered mineralisation at 101m and is still in mineralisation at 106.7m, deepest point at time of reporting.

 

Diamond Drill Hole ZK0001 and ZK0003
Diamond Drill Hole ZK0001 was drilled under SGRDD036 and ZK0003 is being drilled under ZK0001. ZK0001 established a significant increase of width with depth, as SGRDD036 was a shallow hole that intersected 2.72g/t Au over 5m from 7-12 metres downhole including 7.8g/t Au over 1m and 12.35g/t Au over 0.5m. Diamond Drill Hole ZK0001 demonstrated gold-bearing mineralisation and alteration over 21m downhole from 77m – 98m that included 0.9g/t Au over 2m from 79.5m – 81.5m and 1.1g/t Au over 8m from 90m-98m including 3.95g/t Au over 0.5m from 93-93.5m

Assay Tables ZK0001 


ZK0001, total depth 113.7 metres: Diamond Drill Hole ZK0001 demonstrated gold-bearing mineralisation and alteration over 21m downhole from 77m – 98m that included 0.9g/t Au over 2m from 79.5m – 81.5m and 1.1g/t Au over 8m from 90m-98m including 3.95g/t Au over 0.5m from 93-93.5m (ALS Certificate of Analysis BR13102581). Exclusion of results which are below the likely economic cut off grade, does not detract from the understanding of this report. Second hole ZK0003 has encountered mineralisation at 101m and is still in mineralisation at 106.7m.

Location of SUGEC drill target and the Martins Shaft Gold lode within the large NW trending dyke (yellow outline). The green line shows location of the 1.55km long gold-bearing structure currently being drilled. Also shown are the locations of 36 geophysical targets ( ) over satellite image in EL 6483 and EL 7491. Major interpreted structures (potential gold-bearing fluid conduits) are indicated by black lines; historical gold mines/prospects are designated by yellow triangles ().

Previous Drilling
Sovereign Gold has previously drilled seven shallow diamond holes along the 1.55km structure (SGRDD036, 037, 038, 039, 043, 044 and 045).

  • SGRDD036: encountered 2.72 g/t Au over 5m from 7-12 metres downhole including 7.8 g/t Au over 1m and 12.35 g/t Au over 0.5m.
  • SGRDD037: encountered anomalous gold mineralisation. Multi-element analyses showed that this hole penetrated the outer alteration halo of the main gold mineralisation. It indicates that the bulk of the gold mineralised system is still potentially persevered.
  • SGRDD038: encountered 1.16 g/t over 3.0 metres from 39-42m downhole including 1.93 g/t over 1.0m. SGRDD038 was drilled under SGRDD037, established gold mineralisation widening at depth.
  • SGRDD039: encountered 1.07 g/t over 12 metres from 3-15m downhole including 4.93 g/t over 0.6m.  Also 129.6 g/t Ag (silver) over 0.72m from 13.60-14.32 metres downhole including 453 g/t Ag (14.6 ounces) and 0.14% Sb (antimony) over 0.2m.
  • SGRDD043: encountered 1.02g/t over 6 metres downhole from 28-34 metres including 2.01g/t Au over 2.5m from 30.5-33metres, including 3.93g/t Au over 1m from 31-32 metres.
  • SGRDD044 and SGRDD045: encountered shallow anomalous gold over 15.1 metres and 8.2 metres from 6.9-22 metres and 7.9-16 metres respectively.

 

 

Reduction to Pole Magnetic image showing trace on gold-bearing structure being drilled and parallel structure (red dashed lines). A sub-circular magnetic high (enclosed by purple circle) may represent the hornfelsed carapace (‘cooked’ metasediments with disseminated sulphides) above a blind pipe-like pluton. SUGEC is currently designing geophysical surveys to locate such a target with the aim of deep drilling.   

 

Core of ZK0001–Brecciated metasediments flooded with sulphide-bearing felsic intrusive and quartz veining from 78-79 metres (NQ Core 47.6 mm diameter).

 

Core of ZK0001–Metasediments with disseminated sulphides and fingers of sulphide-bearing felsic intrusive from 79-80 metres (NQ Core 47.6 mm diameter).

 

Core of ZK0001–Metasediments with disseminated sulphides and sheeted quartz-sulphide veins from 79-80 metres (NQ Core 47.6 mm diameter).

 

Core of ZK0003–Brecciated metasediments with quartz-sulphide flooding from 105-106 metres (NQ Core 47.6 mm diameter).

 

Core of ZK0003–Black Metasediments with sulphide-bearing fingers of grey felsic dykes from 106-107 metres (NQ Core 47.6 mm diameter).

 

Left ZK0001 – White, phyllic altered (quartz-sericite) felsic dyke in altered metasediments from 93.38-93.52 metres. This dyke exhibits total biotite destruction and sericite-sulphide alteration similar to the mineralisation at Martins Shaft - RHS SGRDD002  – 19-20m downhole.

 

ZK0001 – Quartz sulphide flooded brecciated metasediments from 90.50–90.73 meters (NQ Core 47.6 mm diameter).


Closed spaced ground magnetic and IP surveys are planned to locate conceptual deep drilling, pipe-like target that may have generated the extensive fracture system flooded with sulphide mineralisation and stringers of felsic dykes.

Gold Target Summary
Drilling has confirmed the presence of a large, newly discovered Intrusion-Related Gold System (IRGS) at the Rocky-River Uralla Goldfield.  ‘Proof of Concept’ validates the potential for a major gold discovery.

Sovereign Gold’s well-calculated drill programme has defined a multitude of targets comprising more than 15 separate gold lodes and numerous geochemical anomalies in a large mineralising system over 60 km2.

A detailed low level airborne magnetic and radiometric survey has been completed that revealed the location of many long gold-channelling conduits. Discovery of multiple exploration plays at or near surface including mineralised dykes many metres wide, mineralised structures several hundred metres long, sheeted vein deposits, high-grade narrow veins and shoots in granite and disseminated gold in granite.

Extensive geochemical and geophysical anomalies, some indicating potential large bulk open cuttable, closed-spaced multiple vein systems and stockworks in the order of 1-2 grams per tonne Gold (Au).

66 drill holes recorded intercepts of either ore grade gold mineralisation and/or anomalous to highly anomalous gold values. Rapid success, Martins Shaft, significant Gold discovery.
 

High Gold and Silver Grades in Mineralised structure at Frasers Find
Mineralisation consist of a central high-grade gold-bearing vein – expected to be a deep tapping structure that potentially hosts wide mineralised zones analogous to Dargues Reef (Majors Creek Gold Mine, Braidwood N.S.W., 330,000 ounce IRGS gold lode in altered granite that extends to 500m – limit of drilling).

Over 250 metres long:

  • Silver up to 1,110g/t – 1.11 kilograms / 35.69 ounces
  • Gold up to 76.9 g/t (2.47 ounces)
  • Lead up to 5.45%

 

Goldsworth Mine
Along the structural trend in the north of the Map above is the Goldsworth Mine. This mine was partially developed on two levels, Level 1 at 56m and Level 2 at 89m depth. The orebody is a 1.3m to 1.9m wide quartz-sulphide vein and with alteration zones into the adjacent granite. Grades are variable but ore crushing records indicate grades up to 1oz/t.

The Goldsworth Mine area, mineralised lode constructed with yellow triangular wire frames, with solid shading -gold mineralisation potential present over several kilometres of strike and at depth.

 

 

 

last updated 30/05/2016

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