Location and Access
The Project is located 70km northeast of Wiluna and 25km east of the Jundee operation. Access to the Project is via well maintained country roads to the Millrose Station which is located immediately east of the Project. Further access throughout the Project is via a network of station tracks (see Figure’s 1 and 2). Accommodation and earthworks services are available at Millrose Station.
Figure 1: Regional location and basement geology of the Yandal East Gold Project
The Project lies in the Millrose Domain on the northern section of the Yandal Greenstone Belt (YGB) (Figure 1). The YGB is bound by granitic batholiths to the east (Millrose Batholith) and west (Ward Batholith) and separated into eastern and western domains by a large strike parallel fault located approximately 1km from the eastern margin of the belt. There is distinct metamorphic zoning from amphibolite facies close to the granitoid contacts to lower greenschist in the centre. Granitic intrusions range from diorite to granite. Proterozoic mafic dykes are prominent, trending east-west, cross-cutting the granite-greenstone terrains.
Further south, this belt connects with the main YGB, the host of several significant gold mines including the world class Jundee Mine (7Moz), Bronzewing (4Moz) and Darlot (3.5Moz). The Millrose deposit is located 2km to the east of the Project and has an Inferred Resource of 4Mt @ 2.4g/t Au for 309,000oz. Gold mineralisation at Millrose appears to be controlled by the flexure of a steep, east dipping shear along the Celia Lineament.
Other gold prospects along strike from Millrose include the Warmblood prospect (Alloy Resources Limited, ASX:AYR) that contains 75,000oz of Au @ 2.4 g/t located 20km to the northwest, and the Julius prospect (Echo Resources Limited, ASX:EAR) that contains 335,000oz of gold @ 2.0 g/t located to the south. Gold mineralisation at the Warmblood prospect is confined to narrow, highly strained, steeply west-dipping to sub-vertical, north plunging shoots.
There is only limited bedrock exposure within the tenement area – the basement rocks are typically covered by Quaternary cover such as playa lake clays, aeolian sand and associated sheet wash deposits. Bedrock geology has been developed from interpretation of airborne magnetic data supported by lithological information from drilling (Figure 1 & 2).
The greenstone succession is dominated by deformed mafic volcanic rocks. The majority of the mafic rocks are interbedded with felsic volcanics and fine grained pelitic schists and located on the western margin of the project area. Ultramafic units straddle the prominent Celia lineament which divides the greenstone into the western and eastern domains.
Structures locally within the belt are non-linear, often arcuate, and are disrupted by cross cutting faults. Magnetic highs are observed to terminate for no apparent reason. It is proposed that the repetition and termination points of some of the magnetic highs represent repetition by thrusting and sheath folding parallel to the belt, and termination by sheared-out fold closures.
The best mineralisation in the East Yandal area typically occurs close to the eastern granite – greenstone contact, this contact is not well defined, and interpretation is often hampered by lack of outcrop and alteration which is magnetite destructive. Alteration in these instances may be associated with potentially mineralising hydrothermal events and/or deep weathering within deformed corridors, also potentially mineralised due to structural controls.
The use of modern exploration techniques including geophysics and effective drilling along with a “camp scale” approach to exploration will provide the Company the opportunity for new discoveries.
Previous work programs
The Company is conducting a review of previous exploration and is compiling all of the historical exploration data available for the Yandal East Gold Project. Table 1 summarises the exploration activity at the Project by the previous operators. There has been very little work completed since the late 1990’s with only 35 holes completed since that time.
|1971||1974||Falconbridge||Reported Ni sulphide mineralisation in drilling|
|1989||BHP Gold/Newcrest||Initial report of gold mineralisation at the Millrose Deposit in 1989, leading to the discovery of the Millrose Deposit, 4Mt @ 2.4g/t Au for 309,000oz|
|1991||1993||Marymia||Drilling identifies up to 0.64% Ni in a 5m composite west of Ward (U prospect). c 300 holes completed for gold and base metals|
|1994||1997||Aberfoyle||RAB, Aircore, RC & DD drilling resulting in the discovery of gold mineralisation at Ward. c. 400 holes completed|
|1997||Eagle Mining/Normandy||RAB, Aircore & RC drilling resulting in the discovery of gold mineralisation at Cowza. c. 400 holes completed|
|1997||1998||Mines & Resources Australia||Further Aircore & RC drilling at both Ward and Cowza. c. 600 holes completed|
|2003||2008||Goldstar Resources/BHP||Geophysics, drilling at regional targets including intersection of 4m @ 2.5g/t @ Mizina; total of 35 holes completed|
|2014||2017||Zebina Minerals||Follow up drilling at Cowza and general reconaissance; total of 8 holes|
Table 1: Summary of historical drilling and significant exploration at the Project
The database compilation is ongoing but the initial assessment indicates that 1,868 holes have been completed for 109,491m with all but 44 holes completed in the 1990’s. Approximately half of the holes are vertical RAB holes which are largely ineffective as many do not penetrate either the Quaternary cover or the depleted saprolite, and the vertical orientation has limited effect testing the sub-vertical mineralisation. A further 45% of the holes are aircore with many to shallow and/or oriented vertically and therefore only partially effective. Only 99 RC and 3 diamond tails have been completed at the Project representing only 5% of the total holes completed. The Company believes that the ongoing assessment of the drilling database and a further review of the effectiveness of the historical drilling are critical to determine the true extent of the historical drilling coverage. There is a significant opportunity for discovery in areas of historical drilling due to these complications in addition to the large areas of totally undrilled greenstone.
|Drill Type||No Holes||Metres||Average Depth (m)||Max Depth|
|Aircore||837||60,791||73||176||11||Vertical & -60|
core – 89
Table 2: Summary of drilling type at the Project (nb: database compilation is ongoing)
Echo Resources Limited (ASX:EAR) have assessed the historic drilling at their Yandal Project immediately south of Overland’s Yandal East Gold Project. EAR concluded that only 7% of all historic holes “appear to have meaningfully tested geological structures”. Overland is confident that a review of the historical drilling at Yandal East will yield similar results that could reveal large areas of effectively undrilled greenstone.
Figure 2: Basement geology and drilling at the Yandal East Gold Project
The Project consists of five tenements (in aggregate 327km2) with four granted exploration licences and one exploration licence under application.
Table 3. List of Tenement’s that comprise the Yandal East Gold Project
Overland has executed a binding agreement with Zebina Minerals Pty Ltd (Vendor) whereby Overland has an option to acquire 75% of the Project on or before 28th February 2019. The terms option are as follows:
- Overland will issue The Vendor A$100,000 of OVR scrip, based on the volume weighted average price (VWAP) for the month of August 2017 (Option Shares). Option Shares will be escrowed for 12 months.
- Overland will also issue to the Vendor an equal number of unlisted options (Options) to acquire OVR shares. The Options will have an exercise price of 125% of the VWAP used to calculate Option Shares above, and will expire 24 months from the date of issue.
- Overland is required to undertake A$350,000 worth of expenditure on the Project within the 18 month option period
- Upon issuance of its notice of intent to exercise the option Overland will issue the Vendor an additional A$400,000 of OVR scrip, at a 10% discount to the 20-day VWAP prior to notice of intent. 50% of the shares will be escrowed for 6 months with the balance escrowed for 12 months.
Upon exercise of the Option, Overland and the Vendor will enter into an incorporated exploration joint venture whereby:
- The Vendor retains a 25% free-carried interest, whilst Overland as the JV operator will continue to fund any exploration and pre-development activities.
- Once a decision to mine is made over a defined area or resource, this area will be excised from the exploration JV and a mining JV created over the mining area at the same ratio. The Vendor will be required to contribute to the development expenditure on a pro-rated basis. The exploration JV will remain active over the remainder of the Project.
- Should The Vendor choose not to contribute to the mining JV their interest will be diluted, should they dilute to less than 5% its JV interest shall automatically convert to a 1% royalty.