Overview
Stage | Preliminary Economic Assessment |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Attrition
- Electrostatic separation
- Gravity separation
- Spiral concentrator / separator
- Magnetic separation
|
Mine Life | 15 years (as of Jan 1, 2020) |
The purpose of the Scoping Study was to ascertain the financial benefits of a longer mine life by scheduling production targets from the JORC-compliant (2012) Indicated (7Mt @ 1.1% THM) and Inferred (702Mt @ 1.2% THM) Mineral Resources. The Mineral Resources lie north and directly adjacent to the current granted Mining and Retention Licences and are interpreted to represent the strike continuation of the same body of mineralisation currently defined by the DFS Ore Reserves.
The production targets are scheduled from year 23 when the current DFS Ore Reserves are depleted and additional feed is required. The Extension Case adds 15 years of production to the mine life (total 37.5 LOM). |
Source:
p. 4, 16
Summary:
Coburn is a world-scale mineral sands deposit, containing a rich zircon-titanium HM assemblage, with 20Mt of in-situ HM, low slimes, low oversize and strong geological continuity across and along strike.
Coburn’s Amy deposit was discovered in 2000 after prospectors identified that the ancient coastline at Coburn was an ideal trap-site for heavy mineral sands with its characteristic hook shape.
Mineralisation consists of an accumulation of mainly aeolian sands deposited over a Cretaceous basement of clays, clayey sands and limestone.
A total of 3 dune sequences containing heavy mineral are recognised across the project area.
The Amy South mineralisation has a strike length of approximately 27 km, a width up to 3 km and a maximum thickness of approximately 50 metres. Amy North adds a further 6km in strike length.
IHC Robbins issued (November-2018) JORC compliant Global Mineral Resource estimate of 1.6Bt HM at 1.2% THM (cut-off grade of 0.8%).
Measured-Indicated resources of 726Mt at 1.3% THM contained in the Amy South deposit (doesn’t include Amy North) have been evaluated as part of the DFS and updated Ore Reserve.
Amy South deposit comprises an exceptionally rich heavy mineral assemblage of 22% zircon, 12% rutile-leucoxene and 48% ilmenite.
Indicated-Inferred resources extending north and along strike of the Ore Reserve, totals 709Mt at 1.2% THM which have been evaluated in the Mine Life “Extension Case” Scoping Study.
Summary:
Conventional open pit dry mining in free-dig sand using D11 dozers feeding mobile Dozer Mining Units (DMUs), with in pit tailings deposition and progressive backfill and rehabilitation.
Seeds will be collected from vegetation across the orebody prior to the vegetation being removed by heavy mobile equipment. Collected seeds will be used in the mine rehabilitation process.
Topsoil and Subsoil material will be stripped by dozer or scraper and will be either placed in stockpiles in the vicinity of the pit or placed directly on top of recontoured tails areas. Both topsoil and subsoil will be managed to minimize stockpile duration.
Overburden, where present, will be removed by large capacity bulldozers and placed in the pit void immediately behind the mined-out ore. Interburden removal is carried out by an excavator and the EMU (Excavator Mining Unit). No drill and blast is required.
Ore is pushed by a fleet of D11 manned carry dozers to DMUs (dozer trap), oversize material is wet screened separated from the slurry undersize which is subsequently pumped to the ore processing facilities. The DMU’s are skid mounted and moved on average every 6 days during the LOM.The EMU alternates between overburden removal and ore processing during periods of DMU movement.
Grade control of the ore has been defined through the mine optimisation and scheduling process to achieve the target feed head grade to the plant. Operation efficiency of the dozers will be aided by the application of modern GPS tracking and level control technology.
The mining and related earthmoving activities will be delivered under a contract mining arrangement. The mining contractor will be responsible for efficiently feeding material to the EMU and DMU’s as per the mine plan and also performing the necessary contouring of tails and in-pit slimes, subsoil-topsoil replacement, haul road maintenance, bench management and drainage, in pit dewatering and re-contouring of the completed pit area in readiness for rehabilitation.
Strandline will be responsible for statutory duties, technical services, geology and detailed mine planning, potable water, power and communication systems.
Processing
- Attrition
- Electrostatic separation
- Gravity separation
- Spiral concentrator / separator
- Magnetic separation
Flow Sheet:
Summary:
The WCP receives ore from the mining units and associated pumping system at an average rate of 3,000tph. A high grade 95% Heavy Mineral Concentrate is produced through multiple stages of high efficiency gravity separation and classification technology.
Wet Concentration Plant (WCP). The WCP receives ore from the mining units and associated pumping system at an average rate of 3,000 tph. A high grade 95% Heavy Mineral Concentrate is produced through multiple stages of high efficiency gravity separation and classification technology:
- The WCP beneficiates the heavy minerals (ilmenite, leucoxene, rutile, zircon) and rejects the non- valuable, lighter minerals through multiple stages of high-capacity gravity separation and classification;
- WCP process is designed to produce Heavy Mineral Concentrate (HMC) containing nominally 95% HM;
- The WCP infrastructure is relocatable and is planned to be moved as mining advances along the orebody in years 8, 10, 18 & 19;
Combined production numbers are reported under
Coburn Project
Operational Metrics:
Metrics | |
Ore tonnes mined, LOM
| ......  |
Annual ore mining rate
| ......  |
* According to 2020 study.
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Reserves at April 16, 2019:
Category | Tonnage | Commodity | Grade |
Indicated
|
7 Mt
|
Heavy Minerals
|
1.1 %
|
Inferred
|
702 Mt
|
Heavy Minerals
|
1.2 %
|
Total Resource
|
709 Mt
|
Heavy Minerals
|
1.2 %
|
2020 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
Total OpEx
|
$M AUD
|
......
|
Gross revenue (LOM)
|
$M AUD
|
......
|
EBITDA (LOM)
|
$M AUD
|
......
|
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Corporate Filings & Presentations:
Document | Year |
...................................
|
2020
|
...................................
|
2020
|
...................................
|
2019
|
- Subscription is required.
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