Overview
Stage | Restarting |
Mine Type | Open Pit & Underground |
Commodities |
|
Mining Method |
- Truck & Shovel / Loader
- Longhole stoping
- Cemented rockfill
- Unconsolidated rockfill
|
Mine Life | 7 years (as of Jan 1, 2023) |
Andy Well mine was placed on care and maintenance in 2017.
Andy Well was acquired by Meeka Metals in February 2021 from Silver Lake Resources Limited and currently is a part of the Murchison Project.
The Murchison Project involves a brownfield restart of mining at Andy Well and a greenfield start up at Turnberry and St Anne’s. Andy Well was previously permitted for mining and processing operations, and various licenses and permits remain in place.
Existing infrastructure at Andy Well including workshop, stores, owerhouse and 6km of UG development will be recommissioned for mining activities.
Partial processing facility at Andy Well (ball mill and gravity circuit have been removed) is available and provides alternative development pathway. |
Source:
p. 30-31
Company | Interest | Ownership |
Andy Well Mining Pty Ltd.
(operator)
|
100 %
|
Direct
|
Meeka Metals Ltd.
|
100 %
|
Indirect
|
Andy Well Mining Pty Ltd, a subsidiary of Meeka Metals Limited (Meeka Metals), owns 100% of all Exploration Licenses, Mining Leases and mineral rights for the Project. Andy Well Mining Pty Ltd was acquired by Meeka Metals in February 2021 from Silver Lake Resources Limited (Silver Lake). The Project is managed by Meeka Metals.
Contractors
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Deposit Type
- Porphyry
- Hydrothermal
- Vein / narrow vein
Summary:
Project scale geology consists of Archean aged high Mg Basalt units intruded by north-south striking porphyry intrusives. These are cross cut by east-west striking Proterozoic dolerite dykes. The mineralized quartz vein cross cuts the Archean units but not the Proterozoic dykes.
Andy Well is located at the northernmost end of the north-north easterly trending Archaean Meekatharra- Wydgee greenstone belt, within the Youanmi Terrane. The belt comprises a succession of metamorphosed mafic to ultramafics, felsic and sedimentary rocks interpreted to belong to the Norie Group formerly Luke Creek and Mount Farmer Groups.
The Andy Well local stratigraphy is comprised of a north-northeast striking, sub-vertical (~80º) dipping, Achaean volcano-sedimentary package. The stratigraphy youngs toward the West based on sedimentary textures and immobile element geochemistry of basalts. The local package follows a general transition from a basaltic subaqueaous lava sequence at its base which becomes mafic volcaniclastic dominated before transitioning to a siliciclastic sequence of agrillites and arenites to the west of the Great Northern Highway.
The lowermost unit in the local sequence is a voluminous gabbro unit which is generally massive with a leucocratic texture at its core. West of this unit, a series of at least 3 distinct >200m thick basalt episodes have been recognised texturally and geochemically within the local sequence which are themselves compris ........
Mining Methods
- Truck & Shovel / Loader
- Longhole stoping
- Cemented rockfill
- Unconsolidated rockfill
Summary:
Both open pit and underground mining is planned at Andy Well.
Underground Mining
Underground mining is planned at both Andy Well and Turnberry. The steeply dipping, high grade lodes are planned to be mined predominantly by mechanical means. Decline development will be performed by twin boom electric hydraulic jumbo.
Andy Well ore drive development will be completed by single boom jumbo developing a smaller profile. Long hole stoping is planned for both mining centres with the addition of rock fill at Andy Well to provide geotechnical control within stopes. Underground mining will be managed by the Company with contractors performing development and production activities, operating 24 hours a day, 7 days a week.
Both loose rock fill and cement rock fill (CRF) will be applied at Andy Well to provide further geotechnical control during stoping.
The Andy Well underground mine was designed around the optimised stopes and existing mine development. Only limited capital development is required above 1,200mRL (~280m below surface) due to the existing decline and ventilation development. This development provides immediate benefit to the production plan with early access to Wilber, Suzie, Judy and Judy North lodes from the existing decline. As mining advances, new decline infrastructure will be developed to access deeper mining fronts.
Access to each stoping level is via a level crosscut developed on each stoping horizon. Esc ........
Flow Sheet:
Crushing
The Project will use three-stage crushing to produce P80 of 13.5mm feed for the milling circuit.
The nominal crushing rate is 150tph with double shift operation and 76% crusher utilization. Crushed ore more than the mill requirement overflows the fine ore bin (FOB). Alternatively, the crushed ore is stockpiled by pulling out overflows from the FOB by a front-end loader. The FOB is normally kept full by operating the crushing circuit at a rate exceeding the milling capacity. This allows for crusher maintenance shutdowns when required, without interruption of milling operations.
Crushed ore is withdrawn from the fine ore bin using two belt feeders with variable speed drives. The speed of the belt feeders is controlled by a process loop to the weightometer located on the mill feed conveyor. The mill feed rate is automatically controlled to the selected mill feed rate.
The crushed ore is transferred from the fine ore bin discharge belt feeders to the mill feed conveyor. The mill feed conveyor is fitted with a walkway to one side and a dual idler weightometer linked to the fine ore belt feeder VSD to control the mill feed rate.
A ball mill kibble is located above the mill feed conveyor to feed grinding media to the mill.
A lime silo and feeder are located above the mill feed conveyor. Bulk quicklime is delivered to site and pneumatically transferred to the lime silo. The lime is fed by a variable speed screw feeder onto the mill feed conveyor at a rate controlled by a pH loop in the first leach tank.
Milling and Classification
The milling circuit comprises a single stage 3,850kW ball mill, fitted with rubber liners, discharge trommel and operating in closed circuit with cyclone classification. The mill discharge density is controlled by water addition to the mill feed chute, regulated using a flowmeter and flow control valve. The mill discharge slurry flows through the trommel screen into the mill discharge hopper fitted with a level indicator. The slurry level in the mill discharge hopper is maintained constant by a level control loop to the VSD on the cyclone feed pump motor.
The mill discharge slurry is pumped to a cluster of 10” cyclones for classification to oversize (product which is at the P80 of 75µm for the leach circuit) and coarse undersize. Operation of the cyclones is monitored by a slurry flowmeter and pressure transmitter. The cyclone feed density is regulated by water addition to the mill discharge hopper using a flowmeter and flow control valve.
A fraction (~25%) of the cyclone underflow (coarse fraction) flows to a gravity feed splitter box and will then gravitate back to the ball mill via a pipe and boiler box arrangement. The rest of the cyclone underflow will gravitate back to the ball mill feed chute.
Flow Sheet:
Summary:
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Source:
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Projected Production:
Commodity | Product | Units | 2017 | 2016 | 2015 | LOM |
Gold
|
Metal in ore
|
koz
| | | | 354 |
Operational Metrics:
Metrics | |
Ore tonnes mined, LOM
| ...... |
Ore tonnes mined
| ...... |
Tonnes processed
| ...... |
* According to 2023 study.
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Reserves at July 12, 2023:
Andy Well Mineral Reserve is reported using 2.0g/t gold cut-off grade.
Andy Well Mineral Resource is reported using 0.1g/t gold cut-off grade.
Mineral Resources are reported inclusive of Mineral Reserves.
Category | Tonnage | Commodity | Grade | Contained Metal |
Probable
|
1,800 kt
|
Gold
|
4.3 g/t
|
249 koz
|
Measured
|
150 kt
|
Gold
|
11.4 g/t
|
55 koz
|
Indicated
|
1,050 kt
|
Gold
|
9.3 g/t
|
315 koz
|
Inferred
|
650 kt
|
Gold
|
6.5 g/t
|
135 koz
|
Total Resource
|
1,800 kt
|
Gold
|
8.6 g/t
|
505 koz
|
Commodity Production Costs:
| Commodity | 2017 |
Credits (by-product)
|
Gold
|
-4 / oz AUD
|
All-in sustaining costs (AISC)
|
Gold
|
1,517 / oz† AUD
|
C1 cash costs
|
Gold
|
916 / oz† AUD
|
C2 total cash costs
|
Gold
|
1,718 / oz† AUD
|
C3 fully allocated costs
|
Gold
|
1,809 / oz† AUD
|
† Net of By-Product.
Operating Costs:
| Units | 2017 | 2016 |
UG mining costs ($/t milled)
|
AUD
| 115 | 111 |
Processing costs ($/t milled)
|
AUD
| ...... | ...... |
Total operating costs ($/t milled)
|
AUD
| ...... | ...... |
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Financials:
| Units | 2017 |
Sustaining costs
|
M AUD
|
21.3
|
Revenue
|
M AUD
|
85.7
|
Pre-tax Income
|
M AUD
|
-40.5
|
Corporate Filings & Presentations:
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