Location and History
The Eclipse Gold Project is comprised of a single mining licence (M27/153) and is located approximately 55km NNE of Kalgoorlie. The nearest gold processing plant is at Kanowna Belle, 35km to the south. The licence is accessed by the Yarri Road. This road is sealed to the turn off to Kanowna Belle. While it has not been gazetted, it is a well-used road generally in good condition.
The Eclipse gold mine has had multiple owners since its discovery in 1902. In the period from April 1905 to November 1910 the Eclipse shaft was developed to a depth of 258 feet and produced 954 tonnes @ 24.6 g/t Au for 754.25 oz Au (source: GSWA Mindex database). In the 1990s the shaft was dewatered, refurbished to the bottom level and the collar of the shaft was re-established with concrete.
Prospecting has occurred intermittently on the licence. However, since acquiring the property, Empire has executed a systematic exploration programme comprising soils geochemistry, close-spaced ground magnetics geophysics, and RC and diamond drilling, from which the Company has proven the mineralised envelope at Eclipse is open both along strike and at depth, and identified that there are multiple parallel veins which coalesce around the old Eclipse Shaft.
Regional Geology
Eclipse is situated within the Kurnalpi Terrane, close to the boundary of the prolific Kalgoorlie terrane (high Au and Ni endowment) defined by the major regional Ockerburry Fault system (Figure 1). The surrounding district is dominated by 2.70 Ga mafic volcanic rocks, calc-alkaline complexes, feldspathic sedimentary rocks, and mafic rocks. The western margin of the Kurnalpi terrane comprises slightly younger 2.68 Ga rhyolite-basalt and felsic calc-alkaline complexes and associated volcanoclastic sediments.
The interpreted position of the Ockerburry Fault is within 5-10km of Eclipse but its exact position is poorly defined and may be closer to the western boundary of the Project (Figure 2). Widespread historic gold workings are present in the Eclipse-Gindalbie area, but few larger deposits have yet been discovered which may largely be due to the limited past exploration or geological research previously undertaken in the area. The emerging Whiteheads/Blue Poles discovery of Great Boulder Resources (ASX:GBR) is 15km to the north and the 200,000oz Au Lindsays Project is just 5km to the west. In addition to gold, important Ni, Co, Cu ± PGE magmatic deposits are present in the area which attests to the deep-seated structural framework. Black Swan (Silver Swan) is situated 12km to the WSW and the Carr Boyd layered mafic-hosted deposit is located 33km along strike to the NNW (Figure 3).
Quaternary-aged cover and a deep regolith profile obscures the basement geology throughout much of the licence. Low magnetic response of the local geology has impacted the effectiveness of aeromagnetic and ground magnetic surveys in defining the basement architecture except for a prominent mafic dyke, one of several NNW-orientated dykes within the Kurnalpi Terrane.
Local Geoglogy
Drilling by the Company at Eclipse has confirmed that gold mineralisation is associated with a NW-striking and steeply SW-dipping shear zone, known as the Eclipse Shear, with significant gold mineralisation known to extend over a strike length of more than 200 metres. Mineralisation may connect to the Jack’s Dream area further to the NW giving a total known strike length of the Eclipse system of some 500 metres. High grade mineralisation has also been intersected at Twin Shaft about 120m south of the Eclipse Shear. It is not yet clear if the known mineralisation in the Eclipse area is part of a linked shear system, or separate sub-parallel shear zones.
Diamond drillhole ECDD21_003 intersected the Eclipse Shear in fresh rock which confirmed the presence and orientation of the structure. High-grade gold up to 15g/t was associated with thin foliation-parallel quartz veins and a possible laminated quartz structure, and strong silica-sericite-pyrite-arsenopyrite in the immediate wallrock. This was the first instance of arsenopyrite recognised at Eclipse and it may prove to be useful future indicator of gold mineralisation. Surrounding the high-grade core of the Eclipse Shear, the shear comprised chlorite-carbonate-pyrite alteration, and was weakly gold mineralised being typically <1g/t. Within the fresh rock, short strike length (<50 metres) high-grade shoots are present and appear to extend below the currently drilled area.
Recent Work Programmes
Field work to date at Eclipse has comprised a series of (mostly RC) drill programmes, detailed ground magnetic geophysics, and soils sampling. Drilling has confirmed the existence of a number of parallel veins in addition to the main Eclipse vein, including a different stockwork style of near-surface mineralisation in the vicinity of the Jack’s Dream old workings.
Since August 2020 the Company has completed four exploratory drilling programmes consisting of 118 RC drill holes for a total of 10,081 metres and nine diamond drill holes for a total of 1,100 metres.
The key objectives of the Eclipse RC drilling programme has been to:
- confirm historic drilling data surrounding the main Eclipse shaft;
- target known mineralisation at depth and better define the mineralised lode in proximity to the Eclipse shaft;
- test for a shallow laterite-hosted deposit;
- characterise the mineralisation at the Jack’s Dream, Steinhobel and other old workings;
- test if the mineralised system at the Eclipse shaft continues along strike to the west, towards Jack’s Dream; and to
- establish how the mineralisation exposed by the area known as Twin Shafts links with the Eclipse gold system.
The primary purpose of the Eclipse diamond drilling programme was to:
- add confidence to the mineralisation model and the previous RC drilling around the Eclipse shaft;
- target the Eclipse mineralisation at various depths from surface to characterise the vein-system hosting the gold mineralisation; and to enable geotechnical assessments ahead of mine design.
A strategic technical review revisited all data collected over the licence area of Eclipse and focused on developing a more advanced understanding of the structural controls on the known gold mineralisation. The current database highlights the potential of significant additional mineralisation to be discovered within the licence area as it demonstrates that only 20% of the RC holes drilled to date have penetrated below the gold-depleted regolith zone into fresh rock.
The gold depletion within the highly oxidised zone has meant that much of the near-surface extensional drilling along strike of the Eclipse lode has not added substantially to the mineralisation previously identified. However, drilling at depth at Eclipse has already demonstrated a continuation of the high-grade veins, and further drilling at depth is warranted to confirm and grow the extent of the primary mineralisation and to test for further signs of supergene gold enrichment near the base of weathering. The mineralisation is not adequately closed off in any direction. The plethora of relatively deep artisanal mine shafts in the vicinity of Eclipse supports the conclusion that mineralisation lodes will most likely be found within the transitional and fresh rock domains.
Selected drill intercepts above 3.0 g/t Au.
| Hole_id | Depth From (metres) | Depth To (metres) | Interval (metres) | Au (g/t) | Target |
Phase 1 Drilling Programme – October 2020 | |||||
| ECRC20_009 | 45 | 48 | 3 | 21.96 | Eclipse |
| ECRC20_017 | 49 | 52 | 3 | 3.18 | Eclipse |
| ECRC20_021 | 9 | 10 | 1 | 7.76 | Eclipse |
| ECRC20_022 | 22 | 36 | 14 | 3.78 | Eclipse |
| ECRC20_026 | 0 | 1 | 1 | 6.93 | Eclipse |
| ECRC20_026 | 10 | 11 | 1 | 4.51 | Eclipse |
| ECRC20_027 | 33 | 36 | 3 | 5.37 | Eclipse |
| ECRC20_032 | 26 | 30 | 4 | 4.58 | Eclipse |
| ECRC20_037 | 133 | 141 | 8 | 3.20 | Eclipse |
| ECRC20_039 | 94 | 105 | 11 | 3.04 | Eclipse |
Phase 2 Drilling Programme – January 2021 | |||||
| ECRC21_027 | 33 | 39 | 6 | 5.52 | Eclipse |
| ECRC21_030 | 49 | 54 | 5 | 4.77 | Eclipse |
Phase 3 Drill Programme – April 2021 | |||||
| ECRC21_045 | 126 | 131 | 5 | 3.54 | Jack’s Dream |
| ECRC21_054 | 66 | 70 | 4 | 4.78 | Twin Shaft |
| ECRC21_060 | 53 | 55 | 2 | 3.65 | Eclipse |
| ECRC21_062 | 0 | 1 | 1 | 4.08 | Eclipse |
The Company is gathering the necessary data to update and improve the geological model at Eclipse, with a view to revisiting the resource estimations and pit optimisations in the vicinity of the old Eclipse shaft, and will continue exploration at Jack’s Dream and elsewhere along the mineralised trends to evaluate resource potentials throughout the licence area.
