Youanmi Gold Mine and Near-Surface Gold Resources

  • Venus has entered into 2 option agreements to purchase the historical Youanmi Gold Mine (MLs), and all associated infrastructure and mine village (refer VMC ASX release 28 May 2018).
  • Historical production of 667,000 ounces of gold grading 5.42 g/t from open pit and underground operations between 1908 and closure in 1997.
  • Substantial indicated and inferred resources remain at the Youanmi Mine.
  • The Underground Youanmi Deeps resource has JORC 2012 compliant indicated and inferred resources of 2,400,000 t grading 8.5g/t for 657,900 ounces. This resource is refractory in part.
  • The Near Surface JORC 2012 compliant indicated and inferred resources in eight areas are 10.07 Million tonnes grading 1.65g/t for 532,700 ounces (refer VMC ASX release 29 June 2018).
  • The total JORC 2012 Compliant Resource for the Youanmi Gold Mine is now estimated as c.1.2 Million Ounces of Gold.
  • The Youanmi Gold Mine closed in 1997 when the gold price was around AUD $400 per ounce. The gold price is now AUD $1760 per ounce, transforming the economics for gold mining. The gold price rise of over 4 times since mine closure is very significant for future feasibility studies.
  • Importantly, Venus tenements completely surround the gold mine area and the company controls 40 km of exploration along strike.

 

Figure 1. Youanmi Project Location Map

 

Figure 2. Location of Youanmi Gold Mine MLs and VMC Tenements

 

Youanmi Deeps JORC 2012 Mineral Resource Estimate Summary May 2018

The Youanmi Deeps Project Area forms the deeper extension of gold mineralisation in the Youanmi Main Zones (Pollard, Main, and Hill End). These three zones are contiguous and are situated within the main Youanmi Gold Project Area.

 

 

Table 1. Youanmi Deeps 2012 JORC Compliant Mineral Resource Estimate

Youanmi Deeps Mineral Resource May 2018

Class

Tonnes

Au g/t

Au Ounces

Indicated

808,000

8.1

210,200

Inferred

1,605,000

8.7

447,700

Total

2,413,000

8.5

657,900

Note 4 g/t Au Cut-off

 

Table 2. Near Surface Youanmi Resources JORC 2012

Near Surface Resources

Resource Category

Tonnes
(Millions)

Au Grade g/t

Gold
Ounces

Deposit

       

Youanmi Main

Indicated & Inferred

3.21

2.25

232,000

Youanmi South

Indicated & Inferred

0.71

1.80

41,000

Four Pits

Indicated & Inferred

2.28

1.57

115,000

Commonwealth

Indicated & Inferred

0.57

1.70

31,000

Other Minor Zones

Indicated & Inferred

0.04

3.48;

5,000

Plant Zone

Indicated & Inferred

2.46

0.93

74,000

Palaeochannel

Indicated & Inferred

0.08

1.01;

3,000

TSF2

Indicated & Inferred

0.72

1.40

32,000

Near Surface total Indicated and Inferred

 

10.07

1.65

533,000

 

Figure 3. Youanmi Gold Mine showing Resource Locations and infrastructure

 

 

Exploration Potential at Youanmi Gold Mine

  • In addition to the above resources, considerable potential remains within the Youanmi Project to further define additional gold resources, both near surface and underground.
  • Five separate open pits occur over a 2km strike zone. The gold occurs in multiple shear zone lodes throughout and with the current gold price regime, there is potential to develop a single “super pit” to connect them all in one big open cut. This will be an important aspect of the ongoing studies for the project.
  • Significant drill intersections have been made some 200m below the defined underground resources, indicating that the main ore shoots have strong continuity down plunge.
  • The Exploration Target Potential for Near Surface Deposit is approximately 2.0-2.6 Million tonnes at 1.05-1.30 g/t Au and for Youanmi Deeps is approximately 135,000-200,000 tonnes at 10-15 g/t Au (refer ASX release 29 June 2018).

 

Forward Planning

  • The Company plans to complete the following studies during the due diligence which it aims to be completed by or before 31st December 2018, this will be funded from existing working capital:
  • To complete an extensive review of the drill data base to re-evaluate the existing data.
  • To identify exploration targets adjacent to existing resource models.
  • To assess the drilling program needed to provide infill drilling for the “Super Pit” concept.
  • To prepare a preliminary engineering report in regards to the capital cost requirements to rehabilitate the existing plant and infrastructure.

 

Regional targeting along the Youanmi Shear Zone

Highlights

  • Venus’ tenement area covers approximately 648 sq.km of the Youanmi Greenstone Belt.
  • Multiple EM Conductors  identified  along the prospective Youanmi Shear between the High-grade Penny West and the Youanmi Gold Mines.
  • Eight EM Conductors prioritized for testing along the prospective Youanmi Shear between the high-grade Penny West and the Youanmi Gold Mines (refer VMC ASX release 23 March 2018).
  • Field reconnaissance confirmed the presence of quartz-veined gossanous, sheared outcrops with old gold workings within the northern part of the Penny West gold mine lease, and along strike of EM conductors. All priority conductors on Venus’ ground are under transported cover.
  • The Company is planning further field evaluation of the EM priority targets along the Youanmi Shear Zone in preparation for drill testing.

 

Location

The Youanmi gold Project is located 480km to the northeast of the city of Perth, Western Australia. The project is accessed by the sealed Great Northern Highway for a distance of 418km from Perth to Paynes Find and thence for 150km by the unsealed Paynes Find to Sandstone road (Figures 1).

 

Geological Setting and controls of gold mineralization

The Youanmi Gold Project straddles a 36km strike length of the Youanmi Greenstone Belt, lying within the Southern Cross Province of the Archaean Yilgarn Craton in Western Australia. 

The greenstone belt is approximately 80km long and 25km wide, and incorporates an arcuate, north-trending major crustal structure termed the Youanmi Fault Zone (YFZ). This structure separates two discordant greenstone terrains, with the stratigraphy to the west characterised by a series of weakly deformed, layered mafic complexes (Windimurra, Black Range, Youanmi and Barrambie) enveloped by strongly deformed, north-northeast trending greenstones. The greenstone successions to the east of the YFZ are characterised by a dominant north-northwest orientation. 

The greenstone succession and mafic-ultramafic complex are intruded and enveloped by weakly foliated to massive biotite-muscovite granite and adamellite batholiths. The most prominent of these intrusives, informally termed the Youanmi Granite, occupies the core of a steeply south-plunging anticline, which is confined to the east and west by sheared greenstones. A series of northwest trending splay faults, which appear to provide the primary control on gold mineralisation, diverge from the YFZ and traverse the steeply dipping basal greenstone stratigraphy. The most significant of these is a brittle-ductile structure termed the Main Lode Shear Zone (MLSZ) lying along the western contact of the Youanmi granite. 

The main source of gold produced from Youanmi has been from the MLSZ, which in the Main Pit and Youanmi Deeps underground workings, displays a continuous planar fabric over a strike length of 1,100m and a down dip extent of at least 900m. The MLSZ varies in width from less than 1m to 25m, is oriented more or less parallel to the granite-greenstone contact, and contains multiple gold lodes.

Gold mineralisation is developed semi-continuously over a strike length of 2,300m along the western margin of the Youanmi granite associated with the MLSZ. The principal deposits include Youanmi Main, Hill End, United North, Kathleen, Rebel and Kurrajong6. 

The Youanmi gold lodes are invariably associated with a high pyrite and arsenopyrite content and the primary ore is partially to totally refractory.

The majority of gold produced at Youanmi has come from mineralisation located within hundreds of metres of the granite-greenstone contact. The workings extend from the Main Pit in the south to the Rebel-Kurrajong pit in the north, and to approximately 700 metres below surface elevation. 

Gold mineralised lodes within the project area are seen to cut across lithology types (mafic volcanic, felsic volcanic, and BIF) within the MLSZ. Alteration within lodes typically consists of a sericite-carbonate-quartz-pyrite-arsenopyrite +/- stibnite schist or mylonite (Boddington and Johnston, 1992), and shear zones and lodes contain early stage deformed quartz veins. 

Another mineralisation type occurs within altered granite, such as the lower-grade quartz stockwork within McDowells (southwest boundary of the Kathleen pit), and the higher-grade lode style within United North. Alteration assemblages associated with the mineralisation include silica-sericite-carbonate and chlorite-carbonate in mafics and quartz-kaolin in granite.

 

Regional Geophysical Survey

A high-resolution, helicopter-borne electromagnetic survey (HEM XciteTM survey) was flown by New Resolution Geophysics (NRG™) in February (refer VMC ASX release 30 April 2018). The HEM survey targeted potential conductive horizons along 23 km of the Youanmi Shear Zone that may represent increased sulphide contents related to gold mineralisation such as at the Youanmi Gold Mine and Penny West Gold Mine.  

84 lines spaced 250 m apart for a total of 382 line kilometers were surveyed including the Penny West Mine area (with the consent of the tenement holders). The interpretation of the HEM final survey data by independent geophysical consultants Core Geophysics has identified 25 mid- to late-channel conductors within and adjacent to the Youanmi Shear zone; 8 of these conductors (highlighted in red, see Figure 4) may represent priority targets for sulphide-related gold mineralisation and are considered high priority for follow-up work (refer ASX release dated 23 March 2018).  

Flight lines flown over the historical Penny West Gold Mine and other known gold occurrences north of the mine show that subtle responses are closely associated with the gold occurrences and the mapped shear zone. This suggests that HEM responses to shear/sulphide associated gold mineralisation are detectable as subtle, weak to moderate strength, early to mid-time signals. The HEM survey thus confirmed the correlation of EM responses with known gold mineralization and, hence, similar EM responses on Venus’ ground along the Youanmi shear zone are prospective.  The HEM anomalies were classified and prioritized based on their geological setting and anomaly strength.  All of the priority conductors on Venus’ ground are under transported cover.

The Company is planning further field evaluation of the EM priority targets along the Youanmi Shear Zone in preparation for drill testing.

 

 

Figure 4. Location of EM targets identified from HEM Survey

Figure 4. Location of EM targets identified from HEM Survey