Overview
Stage | Construction |
Mine Type | Open Pit & Underground |
Commodities |
|
Mining Method |
- Truck & Shovel / Loader
- Bench stoping
- Cemented backfill
|
Processing |
- Centrifugal concentrator
- Calcining
- Smelting
- Agitated tank (VAT) leaching
- Concentrate leach
- Carbon in leach (CIL)
- Carbon in pulp (CIP)
- Elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 3.8 years (as of Jan 1, 2020) |
September 2021 - Open pit mining has commenced. |
Source:
p. 62, 127
The Penny Gold Project was the primary asset of Spectrum Metals Limited (Spectrum), which was acquired by Ramelius during the 2020 year.
Summary:
Host stratigraphy for the deposit is a sequence of steeply dipping mafic and ultramafic rocks with minor felsic intrusives. Gold mineralisation is associated with steeply east dipping, quartz-sulphide veins typically 2m to 5m in width. These quartz lodes are visually distinct and typically display sharp boundaries to the mineralisation. The quartz veins are variably massive, laminated or brecciated with a highly variable sulphide assemblage of pyrite, pyrrhotite, galena, chalcopyrite and sphalerite. Some sulphide zones are semi-massive and can comprise 50-90% sulphide. Visible gold can be seen proximal to galena and sphalerite. Pb anomalism is significant with lode Pb grade up to 2%. Silver grade is also significantly higher than typical Archaean lode gold deposits.
Mining Methods
- Truck & Shovel / Loader
- Bench stoping
- Cemented backfill
Summary:
The PFS proposes a partial cutback of the existing Penny West pit to provide a suitable location for the development of the Penny North underground main decline portal and ventilation / egress adits. A small open pit is also planned to be mined on the Magenta lode 1.5 kilometres to the north of the Penny North underground mine subject to the finalisation of the Feasibility Study and final investment decision. Underground development at the Penny Gold Project is scheduled to commence during the 2021 financial year with ore being mined in the 2022 financial year. The mining method consists of a conventional mechanised decline and 20m sub level development. The stoping method is conventional longhole drilling and blasting of up-hole bench stopes with a combination of in-situ pillars and cement rock fill stope support. Ore will be hauled along existing access and government roads to the Mt Magnet plant for processing.
The primary initial focus will be excavation of a 736,000bcm cutback on the existing Penny West pit to facilitate portal development in fresh rock from a position in the pit which is safely accessible. The cutback design incidentally allows recovery of 1,200t @ 15.5g/t of inferred ore.
Penny North Underground Mine and will be accessed from the Penny West Pit and will ultimately be mined to a depth of 180mRL (~315m below surface). Production levels will be spaced 20m floor to floor. Ore drives will be developed to a height of 4.5m, resulting in production drill holes up to 20m in length. All holes are planned to be 76mm up holes.
In order to approach 100% extraction, backfilling of voids will be required. The proposed method is already deployed at the Vivien mine with Cemented Rock Fill (CRF) in every second level. CRF will use development waste material, this material generally has a particle size distribution that provides the fill with the required strength without further crushing or screening. Where possible, development waste rock will be trucked directly to “backfill” stockpiles to limit haulage of waste rock to the surface and back. Using CRF, every second production level (primary level) would be completely backfilled with the intermediate (secondary) levels remaining open with small island pillars left in-situ to provide support to the hanging wall. The Penny West mineralisation left below the pit is generally thinner than Penny North and consequently has not been included in the current mine plan at this stage. Further drilling and evaluation of Penny West is expected during operations.
The underground schedule is based upon a single jumbo developing at a maximum rate of 260m per month and a maximum stoping rate of 11,000t of stope ore per month from a level with each level having 2 production fronts.
Processing
- Centrifugal concentrator
- Calcining
- Smelting
- Agitated tank (VAT) leaching
- Concentrate leach
- Carbon in leach (CIL)
- Carbon in pulp (CIP)
- Elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Source:
Summary:
It is planned for the Penny Project ore to be processed through the Mt Magnet Processing Plant as part of an overall feed blend. Test work has shown that high metallurgical recoveries can be achieved at the current processing grind size of nominally 175µm.
No capital modifications to the processing facility are required in order to process the Penny gold ores. Penny ores are marginally softer and the gravity circuit has been demonstrated to have a capacity well above the calculated gravity gold recovery in the Penny feed blend, and the overall gold production is below peak gold production.
The Mt Magnet processing plant is a conventional CIL/CIP gold plant with single stage crushing, primary SAG milling in closed-circuit with a pebble crusher, and secondary closed-circuit ball milling.
A centrifugal style gravity gold recovery circuit operates on a portion of the secondary milling product hydrocyclone underflow. Gravity gold concentrate is intensively l ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Gold
|
Recovery Rate, %
| 95 |
Gold
|
Head Grade, g/t
| 13.3 |
Projected Production:
Commodity | Units | LOM |
Gold
|
koz
| 238 |
All production numbers are expressed as metal in doré.
Operational Metrics:
Metrics | |
Ore tonnes mined, LOM
| ......  |
Tonnes processed, LOM
| ......  |
* According to 2020 study.
- Subscription is required.
Reserves at June 30, 2020:
Cut-off grade for Resources is 2.0 g/t Au.
Category | Tonnage | Commodity | Grade | Contained Metal |
Probable
|
500 kt
|
Gold
|
14 g/t
|
230 koz
|
Indicated
|
420 kt
|
Gold
|
19 g/t
|
260 koz
|
Inferred
|
200 kt
|
Gold
|
6.6 g/t
|
42 koz
|
Total Resource
|
620 kt
|
Gold
|
15 g/t
|
300 koz
|
Commodity Production Costs:
| Commodity | Units | Average |
All-in sustaining costs (AISC)
|
Gold
|
AUD
|
...... *
|
Assumed price
|
Gold
|
AUD
|
...... *
|
* According to 2020 study / presentation.
- Subscription is required.
Operating Costs:
| Units | 2020 |
Processing costs ($/t milled)
|
AUD
| 20.5 * |
* According to 2020 study.
2020 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
Initial CapEx
|
$M AUD
|
......
|
UG OpEx
|
$M AUD
|
......
|
Gross revenue (LOM)
|
$M AUD
|
......
|
Pre-tax Cash Flow (LOM)
|
$M AUD
|
......
|
Pre-tax NPV @ 5%
|
$M AUD
|
......
|
Pre-tax IRR, %
|
|
......
|
Pre-tax payback period, years
|
|
......
|
- Subscription is required.
Corporate Filings & Presentations:
Document | Year |
...................................
|
2020
|
...................................
|
2020
|
...................................
|
2020
|
- Subscription is required.
- Subscription is required.