Project Development Studies
Scoping Study Outcomes
A Scoping Study into the Wowo Gap Project has been completed by Simulus. (Simulus is a specialist Process and Metallurgical Engineering company with particular strengths in Nickel Laterites).
The Scoping Study concluded that the Wowo Gap Project development options are promising. Nine processing options were studied with typical capital and operating expenses being estimated for each option. Costs were based on an annual raw ore feed rate of 2.7 million tonnes resulting in an annual production of 20,000 tonne per annum nickel product for a 40+ year mine life.
The review process developed a favoured option as the production of mixed hydroxide precipitate via heap leaching. Capital costs for this option were estimated between US$626-860 million, at an estimated operating cost of US$4.41/lb to US42.74/lb respectively. The variation in capital cost is based on provision of acid with the lower cost assuming acid being imported whilst the higher capital cost includes the provision of an acid plant on site.
The Mixed Hydroxide heap leach option has additional benefits in regards to:
- Relative simplicity
- No requirement for the production of hydrogen sulphide gas which has environmental concerns
- Proven technology
Key Outcomes
The estimated NPV of the heap leach development option is estimated to be US$296-608 million at 12% cost of capital, with an IRR of 20.3 - 23.7%. The table below compares the project values based on whether acid is imported or produced onsite.
|
Import Acid |
On-site Acid Production |
||
| Ore Processed | mtpa |
2.7 |
2.7 |
| Annual Nickel sold | tpa contained NI |
20,000 |
20,000 |
| Total Nickel sold LOM | contained Ni |
800,000 |
800,000 |
| Nickel price | US$/lb |
6.80 |
6.80 |
| Cobalt price | US$/lb |
16.00 |
16.00 |
| Capex | US$ million |
626 |
860 |
| Opex | US$/lb |
4.41 |
2.74 |
| NPV | US$ million |
296 |
608 |
| IRR | % |
20.3 |
23.7 |
Pre-Feasibility Study Work
Metallurgical test-work currently scheduled for completion during March is a key phase of the Pre-Feasibility process. High pressure acid leach (HPAL) and column leach tests are currently in progress and will provide leaching characteristics and acid consumption. Atmospheric leach tests are scheduled to begin soon to improve the metallurgical understanding of the leach characteristics of the ore. It is anticipated that additional metallugical test-work will be required to further refine the leaching circuit.
Project Comparison
The following table provides a comparison of other nickel laterite projects where process options, capital and operating costs are listed.
A process plant with an annual output of 20,000 tonnes of contained Nickel is considered to be appropriate for the start-up of the project. 2.7Mtpa of NIckel ore will be processed requiring 40 to 50Mt of ore for a 20 year mine life. Significant resources are available to extend mine life and/or production output in the future.
| Project | Wowo Gap | Ramu | Goro | Gladstone Nickel |
| Capital cost (original estimate) US$M |
625/860 |
1,400 |
3,400 |
|
| Capital cost (actual) US$ |
800 |
1,900 3,000 |
||
| Operating cost US$/lb |
4.41/2.74 |
1.77 to 1.85 |
2.19 |
|
| Final product |
Mixed hydroxide precipitate |
Cathode |
Nickel oxide |
Nickel metal |
| Resource size Mt |
200 |
140 |
240 |
71 |
| Resource grade Ni% |
0.85 |
1.0 |
1.6 |
0.9 |
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