Overview
| Stage | Production |
| Mine Type | Open Pit & Underground |
| Commodities |
|
| Mining Method |
- Truck & Shovel / Loader
- Sub-level stoping
- Longhole open stoping
|
| Production Start | ...  |
| Mine Life | 5.2 years (as of Jan 1, 2020) |
During the financial year Ora Banda declared commercial production at the DGP. The declaration, which was made on 31 March 2021, followed a commissioning period subsequent to the commencement of gold production in early February 2021.
Davyhurst consists of three operating mines Riverina, Missouri & Golden Eagle and 1.2Mtpa nameplate process plant operational.
Riverina mining operations ceased on May 3, 2022. Mining fleet rationalisation is underway, with the aim of reducing the fleet by approximately 40 per cent. This will materially reduce the project’s cost base.
Operations will be streamlined to focus on the mining of the Missouri open pit for the next 24 months and the processing of existing stockpiles. |
Source:
p. 50, 54,57
M30/256, M30/255, M30/103 are held by Carnegie Gold Pty ltd, a wholly owned subsidiary of Ora Banda Mining Limited
Contractors
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Deposit Type
- Vein / narrow vein
- Breccia pipe / Stockwork
Summary:
• Local Geology -The two major rock types within the Waihi deposit are:
o Tremolite/Actinolite/Chlorite Amphibolite. Weakly to strongly foliated, fine to medium grained rocks composed of tremolite/actinolite within a fibrous Mg chlorite matrix. High Mg Basalt
o Fine Grained Basalt. Massive to weakly foliated, very fine grained rock composed of actinolite and plagioclase (albite) with trace magnetite. Tholeiitic basalt
Late stage lepidolite bearing pegmatite dykes striking 060° and dipping steeply 75° north cut across the stratigraphy at several places. A quartz felspar porphyry sub parallel to regional foliation has been mapped in the old Homeward Bound pit. Detailed mapping by Cons Gold of the Waihi and Homeward Bound pits shows the area is dominated by a strong penetrative foliation striking 347° and dipping 75° to 80° west. A second weaker foliation striking 040° and dipping 75° north was also recognised in both pits. Several post mineralisation faults striking approximately 070° and dipping north have been mapped or inferred fromthe drilling. The faults have only minor lateral displacement. Several of the faults are infilled by lepidolite pegmatite.
• Gold mineralisation at Waihi occurs within both the tholeiitic and high Mg basalts. Mineralisation is characterised by multiple loads and broad alteration haloes. Mineralisation also appears to have a moderate northerly plunge of approximately 40° towards 340°. Folding is common at Waihi and n ........
Mining Methods
- Truck & Shovel / Loader
- Sub-level stoping
- Longhole open stoping
Summary:
Mining will be undertaken by both conventional open cut and underground methods. The primary underground mining method will be sub-level open stoping using up-hole benching.
Average annual mine production of 1.2 Mt/a is expected to be achieved in April 2021 following a three month ramp up period. Ore will be trucked via a combination of private and public Level 4 –RAV’s rated haul roads from the five mine sites to a central 1.2 Mt/a processing facility located at Davyhurst.
Open Pit
All open pits within the Davyhurst Gold Project will be mined using selective mining techniques. The alteration associated with the gold mineralisation is visually identifiable, facilitating the enabling the proposed method to be adopted.
The mining fleet will comprise, top-hammer blast hole drills, 120 t or 200 t class excavators and 90 to 100 t class rigid body dump trucks, as well as supporting ancillary fleet. This size and type of equipment is commonly used by owners and contractors alike throughout the Western Australian goldfields. All pits will be drilled and blasted on 5 m benches, with the excavators operating on the full bench height of 5 m in waste and nominal flitch heights of 2.5 m in ore. Ore will be hauled from the pit to a designated Mine-Ore-Pad (“MOP”) stockpile adjacent to each pit. From here, road trains will transport the ore to the Run-of-Mine (“ROM”) pad adjacent to the Davyhurst processing plant.
Underground voids exist w ........
Source:
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Source:
Summary:
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Production:
| Commodity | Units | 2022 | 2021 |
|
Gold
|
koz
| ...... ^ | ...... |
All production numbers are expressed as metal in doré.
^ Guidance / Forecast.
Operational Metrics:
| Metrics | 2021 |
|
Annual processing capacity
| ...... |
|
Waste
| ...... |
|
Ore tonnes mined
| ...... |
|
Total tonnes mined
| ...... |
|
Tonnes processed
| ...... |
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Reserves at June 30, 2021:
The Open Pit Ore Reserve was estimated using incremental cut-off grades specific to location and weathering classification. They range from 0.67 g/t to 0.80 g/t Au. The underground Ore Reserve was estimated using stoping cut-off of 2.1 g/t Au.
The Open Pit Mineral Resource Estimates are reported within a A$2,400/oz pit shell above 0.5g/t, the Underground Mineral Resource Estimates are reported from material outside a A$2,400 pit shell and above 2.0 g/t.
| Category | Tonnage | Commodity | Grade | Contained Metal |
|
Proven
|
410 kt
|
Gold
|
1.4 g/t
|
|
|
Probable
|
5,800 kt
|
Gold
|
2.4 g/t
|
|
|
Proven & Probable
|
6,200 kt
|
Gold
|
2.4 g/t
|
470 koz
|
|
Measured
|
200 kt
|
Gold
|
2.9 g/t
|
|
|
Indicated
|
15,000 kt
|
Gold
|
2.6 g/t
|
|
|
Inferred
|
7,800 kt
|
Gold
|
2.8 g/t
|
|
|
Total Resource
|
23,100 kt
|
Gold
|
2.7 g/t
|
2,000 koz
|
Commodity Production Costs:
| | Commodity | Units | 2021 |
|
All-in sustaining costs (AISC)
|
Gold
|
AUD
|
......
|
^ Guidance / Forecast.
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