Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Crush & Screen plant
- Gravity separation
- Carbon in leach (CIL)
- Cyanide (reagent)
|
Source:
p. 49
Current registered holders of the tenements are Regis Resources Ltd and Duketon Resources Pty Ltd (100% Regis owned subsidiary).
Deposit Type
- Mesothermal
- Vein / narrow vein
Summary:
Moolart Well, as part of the DNO, is a mesothermal gold deposit hosted dominantly in intermediate diorite intrusives but also in dolerite, basalt and to some degree ultramafic rock types. Hypogene gold mineralisation is structurally controlled in fresh rock and to a lesser extent in oxidised rock. Competency contrasts between rock types are thought to pay a major role in providing the architecture in which mineralisation occurs. The gold is associated with multiple local moderate to steep east dipping N-S striking structures. These are offset by a series of NW-SE striking post to syn-mineralisation structures which are also partly mineralised.
Moolart Well is a blind gold deposit with several styles of gold occurring within the regolith profile. In transported regolith extending to 20m depth, a Laterite Ore Zone is defined by a coherent sub-horizontal gold blanket consisting of colluvial ironstone and pisolites in a clayey iron rich matrix. The Laterite Zone has an average thickness of 4m, extends over 5km N-S and 1km E-W and in some areas extends within 2m of the surface. Below the Laterite Zone in the residual regolith is the Oxide Zone extending from 20 to 70m vertical depth with a similar lateral extent to the Laterite Zone. Oxide mineralisation consists of numerous primary moderate to steep 60° east dipping gold bearing structures preserved in the clay rich residual profile and sub-horizontal supergene gold developed in the lower part of the profile. Host rocks for the Oxide Zone are a sequence of moderate to steep east dipping Archaean mafic rocks, including basalt and dolerite sills, and ultramafic flow sequence, intruded by late stage high level diorite and quartz-diorite sills and dykes. Primary hypogene gold mineralisation exists below the Oxide Zone but has been poorly drilled to date.
A model of the lithology and weathering was generated prior to the mineralisation domain interpretation commencing. The mineralisation geometry has a very strong relationship with the lithological interpretation and structure in both the laterite and the oxide/fresh mineralisations. The updated Reserve for Moolart Well includes numerous open pits, including the addition of three new mining areas (Buckingham, Eindhoven and Mitchell).
The approximate dimensions of the deposit are 5,000m along strike (N-S), 700m across (E-W) for both laterite and oxide/fresh. The laterite mineralisation extends 25m maximum from surface, and the oxide/fresh mineralisation has been drilled up to 430m below surface.
Summary:
The mining method assumed in the Ore Reserve study is the same as that currently employed at the Moolart Well Gold Mine, which utilises drill and blast, excavator and truck open pit mining. The laterite pits are pre-stripped and then mined to the horizontal geological contacts. The oxide pits are designed to be developed in a series of progressive cutbacks.
Geotechnical and hydrogeological recommendations have been applied during pit optimisation and incorporated in design with ongoing reviews.
Crusher / Mill Type | Model | Size | Power | Quantity |
Ball mill
|
|
|
|
1
|
Processing
- Crush & Screen plant
- Gravity separation
- Carbon in leach (CIL)
- Cyanide (reagent)
Source:
Summary:
The existing Moolart Well crushing, grinding and CIL Processing facility will be utilised to treat the Ore Reserve. Based on feasibility testwork, actual data and testwork since the commencement of production broad recovery variations have been reflected in domains applied to the Resource model for use in the Ore Reserve estimation. The resultant average recovery factor of the Ore Reserve is estimated to be 85% based on final tonnages and grades of ore types.
The Recovery estimated for ROM Ore Reserves is 89%, and is estimated to be 77% for the Low
Grade Ore Reserves.
The plant design is based on a nominal 3Mtpa throughput rate utilising single stage crushing circuit and single ball mill followed by gravity and carbon in leach circuits.
Recoveries & Grades:
Commodity | Parameter | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Gold
|
Head Grade, g/t
| ......  | ......  | 1.13 | 0.92 | 0.89 | 1.21 |
Production:
Commodity | Units | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Gold
|
koz
| ......  | ......  | 28 | 61 | 77 | 81 |
All production numbers are expressed as metal in ore.
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Operational Metrics:
Metrics | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Ore tonnes mined
| ......  | 0.6 Mt | 0.8 Mt | 2.1 Mt | 2.7 Mt | 2.1 Mt |
Plant annual capacity
| ......  | 2.5 Mt | | | | |
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Reserves at December 31, 2020:
Resources are reported at cut-off grade of 0.4 g/t Au.
Reserves are reported at weighted average cut-off grade of 0.5 g/t Au.
Category | Tonnage | Commodity | Grade | Contained Metal |
Probable
|
7 Mt
|
Gold
|
0.9 g/t
|
200 koz
|
Measured
|
7 Mt
|
Gold
|
0.8 g/t
|
180 koz
|
Indicated
|
21 Mt
|
Gold
|
0.7 g/t
|
460 koz
|
Inferred
|
6 Mt
|
Gold
|
0.7 g/t
|
130 koz
|
Total Resource
|
34 Mt
|
Gold
|
0.7 g/t
|
780 koz
|
Corporate Filings & Presentations:
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Aerial view:
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