The Kurnalpi-Randals Project is located south east of the old Kurnalpi mine workings about 95 km north east of Kalgoorlie, in the Coolgardie Mineral Field in Western Australia.
The project area comprises of:
- Kurnalpi East (Colour Dam, Anti Dam)
- Kurnalpi North (Halfway Hill)
- Kurnalpi South
- Jones Find
- Duchess of York
The Kurnalpi area has a history of gold mining, which available records indicate has produced in excess of 580 kg gold (18,650 ounces) from 14,292 tonnes at an average grade of 40.4 g/t gold. During the reporting period for the annual report, exploration work was carried out on Halfway Hill and Colour Dam prospects.
Regional Geology
The prospects are located in the south eastern part of the Eastern Goldfields Province of the Yilgarn Craton, where the geological and structural settings are complex.
The Eastern Goldfields comprises a series of attenuated northerly trending greenstone belts, which have been intruded by and are enclosed within similarly elongate granitoids plutons and complexes. Anastomising regional scale faults, mostly of sinistral strike-slip shears, dissect the province. However, broad-scale stratigraphic correlations still persist across these structures.
The regional stratigraphy comprises a lower basaltic unit, overlain by komatiite, followed by an upper basalt unit (with komatiite affinities) which in turn is overlain by a sequence of felsic volcanic and volcaniclastic rocks. Clastic sedimentary rocks unconformably overlie this sequence.
The komatiite is interpreted as a regional marker that extends across the Eastern Goldfields. However, other units vary laterally whilst felsic volcanic rocks occur at numerous intervals throughout the sequence. Researchers have subdivided the Eastern Goldfields into tectonostratigraphic domains bounded by major faults.
Recent mapping by the Geological Survey of Western Australia (GSWA) suggest division of the region into domains based on distinct stratigraphic, lithologic and structural features, bounded by regional faults and substantial shear zones such as the prominent Avoca shear.
This feature is readily apparent in the aeromagnetic data. A broad synclinal hinge zone has been identified to the immediate east of the Colour Dam Prospect. The Colour Dam syncline is a complex fold structure comprising a sequence of mafic volcanics overlain by felsic volcanics and fine grained meta-argillites and banded iron formations. The felsic volcanics comprise part of a major eruptive centre, which in the vicinity of Colour Dam was the subject of exploration for volcanogenic massive sulphide (VMS) deposits in the late 1970s.
The Steeple Hill Iron Project was discovered in the Kurnalpi-Randalls area.
Kurnalpi North (Halfway Hill Prospect)
The Halfway Hill Prospect is located 3 km north west of the old Kurnalpi town site and forms part of exploration licence E28/465. Geological mapping of the exploration licence and environs by the Geological Survey of Western Australia along with aeromagnetic and air photographic interpretation by the Company's geologists suggests the presence of favourable host rocks and structures bearing gold mineralisation.
The geology of the Halfway Hill Prospect is dominated by a north-north westerly trending suite of mafic and ultramafic rocks bounded by mafic-intermediate volcanic and dolerite-gabbro intrusives.
The western contact of the mafic-ultramafic sequence is bounded by the Avoca Shear, a major structure considered responsible for localising gold mineralisation in the area.
Much of the tenement area is covered with colluvium and laterite deposits; effectively masking the structural and lithological information over the Prospect land. To date, exploration work at the tenement suggests that the area has good potential for yielding a sizable gold resource.
During 2008, the work included field reconnaissance, search and procurement of previously unavailable information, detailed study of all information, drilling of 1,807 metres RC percussion along 12 holes, sampling, and assaying of samples from the drill program (taken at 1 metre intervals).
Halfway Hill Exploration
An airborne magnetic-radiometric survey is planned for the project area to assist in selecting new drill targets for a 5300 metre drill program (5000 RC percussion and 300m diamond) along 30 holes to test deep extensions of gold mineralisation at the Area 9, Halfway Hill and Jones Find prospects.
Kurnalpi East (Colour Dam-Anti Dam Prospects)
The Colour Dam-Anti Dam Prospects are located 8 km south east of the old Kurnalpi townsite and cover lands of five tenements (E28/699, P28/789, P28/958, P28/993, and P28/994).
At Colour Dam gold and base metal mineralisation occurs in two distinct styles:
- Shear controlled, sheeted vein array quartz-sulphide-gold mineralisation associated with strong quartz-sericite - pyrite alteration.
- Complex brittle fracture controlled crack seal vein arrays of quartz-sulphide-gold associated with widespread quartz-sericite-pyrite alteration of the propylitically altered host dolerite.
During 1970s Colour Dam and its environs was explored for its base metal potential by companies such as, Amax Exploration (Australia) Inc, Aquitaine Australia Minerals Pty Ltd, and ESSO Exploration and Production Australia Inc. Aquitaine drilled eight diamond drill holes (at wide distances apart) and made eight intersections (in 3 holes) of 1m each with zinc values ranging from 1.1% to 1.9%.
The geology at the Prospect largely comprises a basic to felsic sequence of volcanic and volcano-sedimentary rocks ranging from ultramafic komatiites through tholeiitic basalts and dolerites through andesites to dacitic and rhyodacitic volcanic and volcaniclastic end members overlain by late tuffaceous argillites and banded iron formations.
At Colour Dam, the basic volcanic and volcaniclastic rocks are intensely altered to quartz-sericite-carbonate and pyrite is in association with quartz-sulphide vein arrays developed within shear zones associated with gold mineralisation.
In addition to the exploration potential of the Kurnalpi-Randalls Gold Project, the Company has a stockpile of about 5,000 tonnes of material at the Colour Dam Prospect, excavated by an earlier tenement holder, which contains around 2.5 g/t of gold.
Fairstar's drilling in the area has intersected anomalous values of copper, lead and zinc and copper flakes have also been observed in the stockpiles surrounding the Colour Dam pit. The feasibility of heap leaching the stockpile material for gold, and the possible extraction of other metals, will be examined over the coming months. Detailed mapping and channel sampling of the Colour Dam pit faces to understand the pit geology, structure, and mineralisation is also planned.
Kurnalpi South
Background
The prospect area is extensively covered by colluvium and laterite and is largely underlain by a northerly striking sequence of ultramafic, mafic to intermediate volcanics and intruded by dolerite to gabbroic dykes and sills.
The Avoca Shear, which is believed to have acted as a major conduit for gold containing mineralising solutions in the area, traverses to the west of the Area 9 Prospect.
Additionally, late stage, northeast trending secondary shears traverse the prospect and environs in the Kurnalpi Area, and these are considered to have directed the hydrothermal gold bearing fluids suitable for forming of shear hosted-quartz vein array style gold deposits. This view is supported by abandoned gold mine workings, which are mainly aligned (north east) along these faults/shear zones and at intersections between these structures (Figure 6).
In addition to these geological observations, Area 9's potential is further strengthened by the high-grade gold intersections obtained by previous explorers in the area:
- Two 3m intersections @ 7 and 14.2 g/t gold in drillhole KRC 13, 7m @ 11.5 g/t gold in drillhole KRC 24, 11m @ 10.9 g/t gold in drillhole KRC 32, and 2m @ 19.6 g/t gold in drillhole KRC 55.
- Additionally, the gold mineralisation at the Prospect is open at depth along dip and to the northwest.
Area 9 Prospect
The 2008 work programme included field reconnaissance, search and procurement of previously unavailable information, detailed study of all information, drilling of 2,379 metres RC percussion along 25 holes, sampling, and assaying of samples from the drilling (taken at 1 metre intervals).
Duchess of York
Duchess of York Gold and Base-Metals Project
The Duchess of York Project covers land across prospects P25/1856 to P25/1858 and is located at about 70 km south east of Kalgoorlie in the Bulong District of the East Coolgardie Mineral Field of WA.
More than 80 per cent of the project area is covered with colluvium. Recent study of available information suggests that the Project has the potential to host a reasonable size gold resource - both near surface (0-50 metres) and at depth, exceeding 100 metres. To unearth sub-surface geology and structures of the Project area an airborne magnetic-radiometric survey over the Project areas is scheduled to be flown in conjunction with Kurnalpi-Randalls magnetic-radiometric survey.
In late 2010, this area was mapped in detail over anomalous gold areas, revealing that the major quartz veins have an alteration halo around them with minor quartz veins, and this zone was rock chip sampled with the results indicating that it contains the gold mineralisation. The large quartz veins had only weakly anomalous gold values, while the alteration zone had higher gold values. Results are tabulated in Table 1 below, and include anomalous Zn, Ag, Pb, Ni and Cu values.
The detailed mapping has indicated in part the location of the alteration zone, and further mapping to complete this delineation of the alteration zone will be undertaken. Then a follow up RC drilling program will be undertaken to target these mineralised zones at depth.
These deposits are considered suitable for processing via heap leaching, and metallurgical testwork will be conducted to confirm this.
| Sample Number | Au ppb | Ag ppm | Cu ppm | Zn ppm | Pb ppm | Ni ppm | Rock Type |
|---|---|---|---|---|---|---|---|
| DOYANOM4_003 | 2170 | 0.71 | 38 | 33 | 17 | 49 | Alteration zone near quartz vein |
| DOYANOM4_005 | 42 | 0.51 | 119 | 20 | 309 | 23 | Alteration zone near quartz vein |
| DOYANOM4_006 | 678 | 0.14 | 79 | 35 | 13 | 41 | Alteration zone near quartz vein |
| DOYANOM4_007 | 371 | 0.4 | 55 | 12 | 49 | 19 | Alteration zone near quartz vein |
| DOYANOM4_008 | 347 | 0.08 | 24 | 25 | 7 | 38 | Alteration zone near quartz vein |
| DOYANOM4_010 | 544 | 1 | 21 | 19 | 41 | 28 | Alteration zone near quartz vein |
| DOYANOM4_012 | 9 | 16 | 8 | 3 | 732 | 6 | Alteration zone near quartz vein |
| DOY002 | 1 | 0.05 | 22 | 10 | 5 | 499 | Alteration zone near quartz vein |
| DOY005 | 1 | 0.05 | 98 | 203 | 3 | 68 | Alteration zone near quartz vein |
| DOYANOM4_016 | 842 | 0.1 | 72 | 36 | 24 | 61 | Alteration zone near quartz vein |
These anomalous values will be followed up by infill soil sampling and mapping to relate the anomalous values back to geology.
Jones Find
Background
The Jones Find Prospect (P25/1836) is located at about 50 km east of Kalgoorlie and 200m north of the Trans Australia Railway Line and covers about 70 hectares.
Mapping was undertaken and a review of previous drilling indicates that extensive anomalous gold occurs from the top of the supergene enrichment zone at 20 metres depth to up to 175metres down-hole depth in a few deeper holes. Many of the holes in earlier drilling programs were drilled to only 40m, and did not intersect the full thickness of mineralisation. Holes were only analysed for gold, and other drilling at contiguous and nearby deposits indicates that significant copper and silver mineralisation also occurs in the region.
Significant anomalous gold intersections (greater than 2m at 0.3g/t) occur over an area over 400m long by up to 200m wide. Gold grades reach as high as 11g/t. This anomalous zone requires infill and deeper drilling to fully delineate the mineralisation.
A second smaller anomalous gold zone occurs about 500m south.
The company is of the view that a heap leach operation based on leaching gold ore with grades above 0.3g/t could be viable, and plans to undertake ore definition drilling in 2011 to determine the gold resource, and the viability of mining and processing the deposit.
An application has been made for a Mining Lease covering the entire prospecting licence.
Regional Geology
The prospect is located within an Archaean quartz monzonite, known as Juglah Granite. The granite contains highly altered greenstone remnants.
Geology
The prospect is characterised by a total lack of topographical relief and is covered by recent alluvium and colluvium.
Evidence of underlying rock types and structure is confined to old mine shaft dumps and pits, together with several trenches and drill cuttings produced during exploration in the tenement over previous years Lateritic profile in the area is well developed and intersected in drill holes from surface, between 20 and 30 metres.
Based on mine dumps and available exposed mine faces, the tenement is considered to contain a mainly northerly striking, steeply dipping sequence of quartz-sericite-clay and quartz-sericite-biotite rocks which, as observed in the vicinity of old workings, are frequently sheared and schistose. Also, there appears to be a number of intrusive felsic quartz feldspar and feldspar porphyry bodies associated with the general lines of workings.
Structurally, the tenement is located on the eastern flank of the south plunging Bulong anticline. The western margin of the underlying granitoid basement coincides with a major northwest striking shear (Majestic shear/fault). The Jones Find Prospect is inferred to lie on a subsidiary splay of this major shear zone.