Overview
Stage | Permitting |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Solvent Extraction
- Sulfuric acid (reagent)
- High Pressure Acid Leach (HPAL)
|
Mine Life | 30 years (as of Jan 1, 2018) |
The Owendale Project in New South Wales has the potential to be Australia’s first scandium producer with a shallow depth allowing open-pit mining, exceptionally high scandium grades and appreciable cobalt, platinum and nickel credits. |
Summary:
The Red Heart deposit is located within Exploration Licence EL7644 which is 100% owned by Platina Resources Limited and was granted on the 2 December 2010. Renewal has been offered for a further term of 5 years expiring in 2020.
The mineralisation at the Red Heart mine site comprises a laterite profile developed over a Devonian age Alaskan-style intrusive complex that can be divided into a mafic-felsic series (monzonite) and an ultramafic series. The ultramafic series comprises dunite-wehrlite, olivine-pyroxenites and olivine-clinopyroxenite rocks. The relative abundance of nickel, cobalt, scandium and platinum in these ultramafic rocks has been enriched to higher grades in the laterite profile due to either a residual or supergene enrichment processes. The variations in element abundance in the original ultramafic basement rock affect the enriched concentrations in the laterite along with the development of the laterite and any erosion of the laterite profile.
The types of laterite-hosted mineralisation identified thus far show strong correlations with certain lithologies, including platinum-copper mineralisation overlying dunite-wehrlite rocks with variable cobalt, nickel and gold content; cobalt-nickel mineralisation with platinum credits associated with the underlying olivine pyroxenites; and elevated chrome and scandium has been noted where dunite-wehrlite lithologies predominate but mainly occur with clinopyroxenite lithologies.
Summary:
The mine operation and mining fleet will encompass three operational areas:
-Mining of ore and waste rock;
-Haulage of ore to the Plant Site and back-haulage of residue to the Mine Site;
-Placement and encasement of residue in-pit and back-filling to allow for remediation activities.
Laterite ore is recovered from the deposits using free digging, open pit mining techniques utilising hydraulic excavators and Moxy mine trucks. A mixed ancillary fleet will be available to support load & haul, stockpile management, rehabilitation and in-pit dumping of waste and residue from the processing plant at Condobolin.
Mining will be conducted on a campaign basis. At full production, stage 1 ore mining will comprise 23,300 tonnes per annum, and stage 2 at 46,600 tonnes per annum.
Mining will generally be undertaken in a manner that will complete the excavation of individual cut-backs prior to any dispatch of feed to the plant. The plant feed will then comprise a blended parcel of similar grade material being fed over a period of time, up until depletion of that cut- parcel, after which a new cut-back is commenced and fed. This process is suited to campaign mining and will allow periodic supervision of grade control, which will minimise mining supervision and overheads. As the plant expansion stages are implemented and throughput increased, the ore mining will approach a continuous operation, however the campaigns of cut-back development will continue to maintain the same ore feed through a blending strategy.
Back-filling of the pit will commence immediately on completion of each cut-back. This will include initial capping of the floor with compacted clay before the build-up of the residue encasement walls and residue placement in the progress sequence. The residue cells will be constructed as an internal pyramid structure at an angle that will permit mining of the neighbouring strips at a later date. The wedge between the residue cell and the pit wall will be back-filled with waste or low-grade material on at least two sides with open faces towards the working pit cut-backs and the next immediate mining strip. The back-fill operation will maintain a safe working back-fill bench and will stabilise the residue emplacement structure long term. It will also allow back-fill ramps to provide access to upper benches as the pit fills. This arrangement ensures that Ore Reserves are not sterilised with residue back-fill and safeguards allow full ore recovery. Ore is trucked to the Plant Site located at Condobolin, 70 km by road using A-double road trains. The trucks tip the ore onto a stockpile at the Plant Site and return with the residue for mine rehabilitation.
Mine development includes mining, backfilling and rehabilitation. The development will be undertaken on individual blocks of 25 metres by 12.5 metres or 25 metres by 25 metres pit floor pits and progressive cutbacks. These will be arranged in strips of three cuts wide and taken in successive slices of 25 metres by 75 metres on the pit floor or about 100 metres wide at surface. The initial planned strip is 330 metres in length but this will vary depending on the final pit limit.
Flow Sheet:
Processing
- Solvent Extraction
- Sulfuric acid (reagent)
- High Pressure Acid Leach (HPAL)
Flow Sheet:
Summary:
The process flowsheet is designed to recover scandium via high pressure acid leaching and solvent extraction (SX), including:
-An ore preparation circuit incorporating crushing, screening and grinding;
-Ore slurry from the ball mill is heated in self-cleaning indirect heat exchangers, using a thermal fluid. The hot slurry is leached at 255°C with concentrated sulphuric in an autoclave for 90 minutes. After being let down to atmospheric pressure the slurry is clarified and the pregnant leach solution (PLS) is pumped to the SX circuit;
-The SX process developed by Element 21 extracts scandium from the PLS. Following an impurity removal step the scandium is recovered as a hydroxide, with a further refining stage generating a 99.99% scandium oxide product; and -Barren solution and leach residue are treated by two stages of pH adjustment to neutralise all free acidity and precipitate heavy metals. The resulting slurry is dewatered on a pressure filter, producing a competent t ........

Projected Production:
Commodity | Units | Avg. Annual |
Scandium
|
t
| 40 |
All production numbers are expressed as oxide.
Operational Metrics:
Metrics | |
Stripping / waste ratio
| 1.9 * |
Annual mining capacity
| 46,600 t of ore * |
Annual production capacity
| 40 t of sc2o3 * |
* According to 2018 study.
Reserves at December 13, 2018:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
3,054 kdmt
|
Scandium
|
575 g/t
|
|
Proven
|
3,054 kdmt
|
Nickel
|
0.13 %
|
4,054 t
|
Proven
|
3,054 kdmt
|
Cobalt
|
0.1 %
|
2,945 t
|
Proven
|
3,054 kdmt
|
Sc2O3
|
|
2,696 t
|
Probable
|
972 kdmt
|
Scandium
|
550 g/t
|
|
Probable
|
972 kdmt
|
Nickel
|
0.08 %
|
767 t
|
Probable
|
972 kdmt
|
Cobalt
|
0.07 %
|
654 t
|
Probable
|
972 kdmt
|
Sc2O3
|
|
816 t
|
Proven & Probable
|
4,027 kdmt
|
Scandium
|
570 g/t
|
|
Proven & Probable
|
4,027 kdmt
|
Nickel
|
0.12 %
|
4,821 t
|
Proven & Probable
|
4,027 kdmt
|
Cobalt
|
0.09 %
|
3,599 t
|
Proven & Probable
|
4,027 kdmt
|
Sc2O3
|
|
3,512 t
|
Commodity Production Costs:
| Commodity | Units | Average |
Cash costs
|
Sc2O3
|
USD
|
525 / kg *
|
Total cash costs
|
Sc2O3
|
USD
|
592 / kg *
|
All-in sustaining costs (AISC)
|
Sc2O3
|
USD
|
634 / kg *
|
Assumed price
|
Sc2O3
|
USD
|
1,550 / kg *
|
* According to 2018 study / presentation.
2018 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
Initial CapEx
|
$M USD
|
......
|
Sustaining CapEx
|
$M USD
|
......
|
Total CapEx
|
$M USD
|
......
|
After-tax NPV @ 8%
|
$M USD
|
......
|
After-tax IRR, %
|
|
......
|
After-tax payback period, years
|
|
......
|
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Mine Management:
Job Title | Name | Profile | Ref. Date |
.......................
|
.......................
|
|
Sep 15, 2021
|
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