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Trojan Gold Project

Introduction

The Trojan Gold Project is located approximately 55km ENE of Kalgoorlie in Western Australia, situated in Australia’s most productive gold region amongst several multi-million ounce production centres (Figure 1).  The Company has the right to acquire 100% of the Project under the terms of an option agreement with Westgold Resources Limited (“Westgold”; ASX:WGX).

Historically ~130,000oz of gold have been produced from two open pits within the Project area. The last ore was mined in 2004, when the gold price was circa US$425/oz.

The remaining shallow JORC compliant resources comprise 145,000oz of gold. These provide the Company an opportunity to generate cashflow in the near term.  The option agreement with Westgold includes the right to toll-treat any ore produced from the Project area through Westgold’s Jubilee Processing Facility.  This provides Overland a low-CAPEX development route.

Minimal exploration has been conducted at the Trojan Gold Project since mining ceased in 2004.  With over 24km2 of tenure, there is considerable exploration upside.

 

Figure1LocationOfTheTrojanGoldProjectWesternAustralia400WideApr17

Figure 1. Location of the Trojan Gold Project, Western Australia
(including regional geology).

 

Regional Geology

The Trojan Project is located on the eastern limb of the south plunging Bulong Anticline, in the Norseman-Wiluna Greenstone Belt. The geology of the limbs is dominated by mafic and ultramafic volcanics and intercalated sediments intruded by dolerite sills. In the core of the anticline felsic and mafic volcanics and sediments are intruded by granitoids. Outcrop in the area is scarce, with the best exposure of bedrock found in the Trojan and Transfind pits and on topographic highs.

 

Figure2GeologyOfTheTrojanGoldProject400WideApr17

Figure 2. Geology of the Trojan Gold Project including location of historic open pits, current prospects, and cross sections

 

Local Geology

The Trojan Deposit is underlain by mafic volcanics in the south and a multiphase porphyritic granite complex in the north. Two large east-west trending dolerite dykes crosscut the Project area to the north and the south of the Trojan pit (see Figure 2).

Mineralisation at the Trojan deposit is associated with a NNE trending brittle shear containing multiple sub parallel lodes dipping 60° west and hosted by granites (quartz syenite), porphyry, and in the extreme southern portion, inter-fingered basalt and granite.

Alteration is characterised by distinctive pink to red haematite staining, quartz veining, silica flooding and pyrite. The pyrite occurs as disseminated crystals and indiscrete fine grained stockworks within the lodes. The haematite is broadly associated with moderate grade mineralisation. The best indicator of significant mineralisation is silica flooding with fine grained disseminated pyrite. There is also a pervasive potassic alteration of the granite, which has a similar appearance to the haematite staining, but is not necessarily related to gold mineralisation. There is also usually quartz veining in or around high-grade intersections.

JORC Compliant Resources

The Trojan Gold Project hosts JORC compliant resources of 2.8Mt at 1.61 g/t gold for 144,800oz of gold, as summarised in the table below:

 

Classification Tonnes Grade (Au g/t) Ounces of Gold
Indicated 1,679,908 1.72 93,117
Inferred 1,114,431 1.44 51,696
Total 2,794,339 1.61 144,814

Table 1. JORC compliant resources at the Trojan Gold Project, using a 0.70 g/t Au cut off

 

It is noted that no remaining mineralisation at the Transfind Deposit is included in the current JORC resource estimation, as very little work has been completed there since the completion of mining in 1992.

Mining History

Trojan Open Pit (M25/104)

The first reported modern exploration in the area took place in 1972. This resulted in the delineation of some 165,800t @ 2.4g/t Au at the Trojan Deposit. Further exploration was undertaken by Endeavour Oil NL in 1976. Their drilling delineated some 460,000t @ 1.7g/t Au. During 1981, Southern Cross Batteries Pty Ltd mined ore from the area and treated it at the North Kalgurli mill. A recovery of 86.6% was achieved from an estimated head grade of 1.35g/t Au.

In 1986-87 Mt. Martin Gold Mines NL undertook a program of RC drilling and delineated a resource of 411,000t @ 2.12g/t Au. Detailed geochemical sampling in 1987/88 revealed a strong gold anomaly some 300-400m south of the known mineralisation. Follow up RAB drilling located ore at approximately 30m vertical depth, beneath a zone of intensely leached and weathered rock. With further RC and diamond drilling, this mineralisation was found to connect with the main mineralisation at the Trojan Deposit to the north. A measured resource of 2 million tonnes at a grade of 2.2g/t Au was identified to a depth of 100m using a 1 g/t Au cut-off.

In 1990, Mt Martin Gold Mines NL submitted a Notice of Intent for the recommencement of mining at the Trojan Project, and approval for the excavation of a trial pit was granted. This trial was delayed for commercial, reasons.

In 1994 Titan Resources NL merged with Mt Martin and took over ownership of the mining lease. Exploration during the 1990s included surface geochemical surveys and RAB and RC drilling to assess the potential over the remainder of the tenement away from the known resource.

New Hampton Goldfields Limited purchased the tenement from Titan Resources NL in April 1999.

During 2000 New Hampton outlined a resource of 2,154,000t @ 2.17g/t Au. Mining of the Trojan Deposit began in September 2000 and continued until July 2004. The last ore was milled in October 2004 (when the gold price was circa US$425/oz). Total production was 1,974,318t @ 1.97g/t for 125,129 ounces of gold. The maximum depth of the final pit was approximately 130m. Grade control drilling had been completed in advance of a Stage 8 open pit cut-back, but this ore was never mined.

In 2001 Harmony Gold Mining Company acquired New Hampton Goldfields Limited. Dioro Exploration NL subsequently acquired the South Kalgoorlie Operations, including the Trojan Project, from Harmony (in 2007). In 2010 Avoca Resources Limited acquired Dioro. Then in 2011 Avoca and Anatolia Minerals Development Limited merged to become Alacer Gold Corp.

In September 2013 Metals X Limited acquired Alacer’s WA gold business, including the Trojan Project. In December 2016 Metals X Limited completed a demerger, whereby the parent company controlling its gold assets, including the Trojan Project, became Westgold Resources Limited.

Transfind Open Pit (Location 41)

At the nearby Transfind Deposit (within Location 41) gold mineralisation is hosted by a relatively massive rhyolite /dacite unit within a sequence of basalts and bedded volcanoclastics. The mineralisation lies within a north northeasterly trending brittle shear zone. with the broadest mineralisation being where the shear is cut by northwesterly trending faults. Quartz veining is widespread.

Limited available records indicate that between July 1991 and February 1992 Imperial Resources NL operated an open pit at Transfind that produced 31,050t of ore grading 4.9g/t Au (4,892oz Au) from a resource of 69,000t @ 5.7g/t Au (12,646oz Au).

 

Figure3AerialPhotoShowingTheExtentsOfTheTrojanAndTransfindOpenPits400WideRevisedApr17

Figure 3. Aerial photo showing the extents of the historic Trojan and Transfind open pits within the Trojan project

 

Exploration Potential

Most of the previous drilling, including drilling at the Trojan pit itself, has been shallow leaving room for potential resource expansion at depth. In addition, considerable unmined, already defined resources remain below and along strike from the Trojan Pit (see Figures 4-6).  Overland considers there is considerable potential to delineate additional resources with further drilling in and around the existing pits and resources.

Similarly at the Transfind pit there has only been shallow drilling. This drilling does, however, indicate that high grade resources remain unmined at the Transfind Pit.  Although these resources are yet to be classified as JORC compliant, the cross sections in Figures 7-9 illustrate the presence of unmined mineralisation.

In addition to the targets immediately around the two historic open pits, numerous coherent geochemical anomalies and prospects have been delineated across the Project area. These comprise high quality shallow exploration targets.  Indeed, large parts of the Project area remain undrilled or under-drilled, particularly in the northern portion of Location 41 (see Figure 2). These targets and undrilled areas will be subject to systematic further exploration.

 

Figure4TrojanCrossSection10 000N400WideApr17

Figure 4. Trojan Cross Section 10,000N showing the extents of the historic open pit at the Trojan Deposit and unmined resources located immediately beneath the Deposit.

 

Figure5TrojanCrossSection10 200N400WideApr17

Figure 5. Trojan Cross Section 10,200N showing the extents of the historic open pit at the Trojan Deposit and unmined resources located immediately beneath and adjacent to the Deposit.

 

Figure6TrojanCrossSection10 400N400WideApr17

Figure 6. Trojan Cross Section 10,400N showing unmined resources located immediately along strike (to the north) from the Trojan open pit.

 

TransfindPitSections300WideApr17

Figure7TransfindCrossSection10 730N400WideApr17

Figure 7. Transfind Cross Section 10,730N showing unmined resources immediately below the southern extent of the Transfind pit

 

Figure8TransfindCrossSection10 880N400WideApr17

Figure 8. Transfind Cross Section 10,880N showing unmined resources immediately below the deeper portions of the Transfind pit

 

Figure9TransfindCrossSection10 960N400WideApr17

Figure 9. Transfind Cross Section 10,960N showing unmined resources continue immediately north of the Transfind pit