Yarri Range Project
The Company is currently focusing on its Yarri Range Project development, comprising 2 exploration licenses, The Yarri South sub-project, covering 58 square kilometers comprising of tenement E31/859; and The Horse Rock Bore sub-project, covering 39.2 square kilometers comprising of tenements E31/887. Which total area of 97.2 square kilometers, that are prospective for gold exploration, located in the Eastern Goldfields of Western Australia, approximately 170 km northeast of Kalgoorlie around the Laverton Tectonic Zone.
The Project area is conveniently accessible via the Yarri/Pinjin Road running through the tenements and connects to the existing haul road network of the Eastern Goldfields and the Goldfields Highway.
The Project is situated in a place historically associated with gold mining activities.Independent studies of regional gold prospectivity have all indicated that the Yarri Range area has high prospectivity for discovering significant mesothermal (Archaean) gold mineralisation. The historical recovery of more than 500 kg of gold from surface workings (0 – 20 m) along the shear zone indicates the possibility for discovery of additional mineralisation at depth. Field and assay data have suggested the likely extension of gold mineralization at depth in the Yarri Range Project area.
Modern and systematic exploration approach will be implemented on the Project with the aim of determining a JORC Code mineral resource from target areas.
Figure 1 – Project Location
As a first phase of exploration undertaken by GFI a high level targeting exercise identified three distinct magnetic trends that persist through the project. The aircore drilling was designed to provide a first pass test across these targeted trends to test for geological controls and any gold anomalism (Figure 2).
Figure 2 – Program Proposal
Key findings from the drilling include (Figure 3 and Tables 1&2):
Assay results identified hole GAC012 as containing what is considered a strongly anomalous gold response. Assaying returned a result of 6m @ 40ppb Au (60‐66m) including 2m @ 59ppb Au (64‐66m).
The result was an “end of hole” result is interpreted to be part of a classic “interface gold dispersion halo” that can lead to the discovery of more significant oxide and primary gold mineralization.
The mineralisation was associated with a sheared sericitic altered volcaniclastic sediment containing minor quartz veining.
There are currently no constraints along strike to the north or south of this result and adjacent drilling is at least 200 metres away.
Figure 3 – Drilling Results
As previously reported (ASX announcement: June 2016 Monthly Report), a field mapping and sampling trip was completed at the Company’s Horse Rock Project, Western Australia. The aim of the field trip was:
1. Assess the fertility of potential source intrusions which may contain Gold or Base metal mineralisation
2. Sample possible source rocks within the project area
3. Sample Soil near old workings
4. Develop relationships with local pastoralists
5. Create an accurate track log for future work programs
In order to achieve these objectives several days were spent assessing access, meeting with the station owners, assessing the geology in the field and then undertaking a number of soil transects and rock chippings across key geological features and units.
Figure 1 -- Tenement map showing new applications (ELA31/1121 and ELA31/1122)
The most significant result was returned from an area of historical mining activity. Rock chip samples were collected and returned a best result of 14.9g/t Au. The importance of this result is the fact that ithighlights a regional shear zone that wraps around a granitoid intrusive. This setting is very similar to that at the nearby Porphyry Gold Deposit.
The shear zone that can also be seen in the airborne magnetic data extends for approximately 10km on the company’s tenements. An assessment of historical exploration data does not demonstrate that drilling has been undertaken at any point along the shear zone.
In addition to the shear zone target a series of “spot” magnetic features have been observed and are considered to be viable exploration targets that require further evaluation.
Figure 2 -- Target Summary Plan
- GAC014 – 4m @ 16ppb Au (16‐20m)
- GAC017 – 16m @ 15ppb Au (12‐28m)
- GAC018 – 2m @ 28ppb Au (20‐22m)
- GAC043 – 4m @ 26ppb Au (16‐20m)
Although the results are not considered ore grade, they do highlight two distinct mineralized horizons that will provide the focus for additional exploration. Most of these horizons are concealed below recent cover sequences (sheet wash, alluvium and colluvium), this would render traditional surface exploration techniques such as soil sampling and rock chipping ineffective, drilling beneath the cover will be required to further explore this zone.
Two areas have been identified within this trend for further exploration: firstly a magnetic high, highlighted in Figure 2, and secondly; closer to the granitic intrusion where theoretically, increasing structural complexity would be a more favorable environment for significant gold mineralisation – this setting is analogous to the nearby Porphyry Gold Deposit.
Eastern Shear Zone ‐ E31/887
9 aircore holes for 605m were completed across three traverses at the Eastern Linear Trend Prospect within tenement E31/887. Drilling was infilling around the previously identified anomaly (GAC012 – 6m @ 40ppb) and also testing along strike for mineralisation continuity.
Assaying did not return any further significant results meaning. At this point, the primary source of mineralisation has not been identified, RC drilling would be needed to penetrate the fresh rock beneath the previously identified anomaly to identify the source.
Stark Prospect ‐ E31/859
10 aircore holes for 294m were completed at the Stark Prospect within tenement E31/859. Drilling was targeting a magnetic feature associated with an interpreted shear zone. Drilling intersected minor alluvial and colluvial cover sequences above a package of predominantly basaltic and mafic intrusive rocks with minor sediments. Very minor alteration and quartz veining was observed. A magnetite enriched mafic intrusive is interpreted as the magnetic feature that was targeted from geophysical imagery.
Assaying did not return any significant results. The regolith profile was noted to be thin, possibly ‘stripped’ and therefore the use of aircore drilling as an exploration technique at this prospect may not be effective as the technique relies upon the dispersion of mineralisation within the regolith to vector towards the primary source. The prospect will be further reviewed before any further exploration.