Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
- Heavy Minerals
- Rutile
- Ilmenite
- Zircon
|
Mining Method |
|
Processing |
- Electrostatic separation
- Desliming
- Spiral concentrator / separator
- Flotation
- Magnetic separation
|
Mine Life | 2039 |
Sierra Rutile’s current mining and mineral processing operations at Area 1 include four wet concentrator plants (WCPs); a mineral separation plant (MSP). Sierra Rutile also includes Sembehun project which is scheduled to stert constraction in 2024.
Sembehun is one of the largest and highest grade natural rutile deposits in the world. |
Source:
p. 127
Sierra Rutile is a wholly owned subsidiary of Iluka Resources (Iluka).
Summary:
The Sierra Rutile Area 1 (the Gangama and Lanti Deposits and other deposits within SRL’s current operations in Sierra Rutile Area 1) consists of a series of prominent hills and slight undulations with an elevation range of 0.9 meters above sea level (masl) along the mangroves, to 322 masl with the highest point being at Gbangbama Hill. The existing dredge ponds and rutile deposits are situated around the Imperi Hills region on the western and south-western extent, with the Lanti and Gangama expansion situated within the alluvial plains and mangrove swamps to the north west. The hills in the region have relatively steep slope angles and form prominent features in the landscape. The majority of the area adjacent to the hills comprises undulating, broad expansive fluvial plains, becoming increasingly flat towards the mangrove swamp areas.
The local geology is described as Tertiary aged alluvial deposits overlying the Precambrian high-grade quartzo-feldspathic-garnet gneiss (charnockite). The SR Area 1 heavy mineral sands placer deposits are hosted in the Bullom sediments which were deposited following a Tertiary marine regression with seas levels some 100 m below current levels. Mechanical and chemical weathering liberated heavy minerals from the underlying Kasila Group which were deposited in pre-incised channels.
Estuarine and marine unconsolidated sediments are located to the west of the major watershed located within the centre of SR Area 1. In contrast, alluvial and elluvial sediments were deposited subaerially to the north-east of the watershed. Several cyclic sequences comprising poorly sorted clastic gravels overlain by sands and clayey silts are preserved. Hard lateritic inclusions are common but are generally associated with the upper portions of the sequence.
The heavy minerals are generally angular and display little evidence of transport over long distances or extensive reworking. Grades rapidly decrease downstream with sand replacing the argillaceous material within the matrix.
Summary:
Sierra Rutile’s current mining and mineral processing operations at Area 1 include four wet concentrator plants (WCPs); a mineral separation plant (MSP) and associated infrastructure; residential camps for senior and management staff; and a dedicated port facility (collectively referred to as Area 1). Sierra Rutile also holds one of the world’s largest known natural rutile deposits, the Sembehun Project.
Mineral reserves at Area 1 is represented by Gangama, Gbeni North, Lanti and Taninahun deposits. Mineral resources for Area 1 extension are comprises Pejebu, Ndendemoia East and Ndendemoia West deposits.
GANGAMA
Mining at Gangama involves the excavation of ore using a conventional load and haul method to deliver ore from the Gangama deposits to two adjacent WCPs (known as DM2:1 and DM2:2). Ore is excavated in the pit and delivered to the Run of Mine (ROM) stockpile or direct to the feed hopper.
TANINAHUN
Taninahun deposit is located within Area 1, approximately 6km northeast from the current Gangama operation. Mining is planned to commence in the second half of 2022 with a contractor truck and excavator operation. Ore from the Taninahun deposit will be hauled to the existing Gangama
DM2:1 and DM2:2 plants. The ROM ore will undergo primary mineral processing to produce HMC as is the current process outlined above.
GBENI & LANTI
At Gbeni and Lanti, two separate WCPs are operated (DM1 and DM4). In both cases, ore is delivered to in-pit mining units (mobile mining units or MMUs). Depending on operational constraints the MMUs are fed by an excavator either via stockpile or directly from dozer push.
PEJEBU AND NDENDEMOIA
The Pejebu and Ndendemoia deposits, comprising Indicated Mineral Resources of 18.6Mt at 1.0% rutile grade for 0.18Mt of contained rutile and 18.3Mt at 1.0% rutile grade for 0.18Mt of contained rutile respectively, are located less than 5km south of the MSP within the Mining Lease. Subject to completing the technical and operational planning activities required to convert Pejebu and Ndendemoia Indicated Mineral Resources to Ore Reserves, mining at Pejebu and Ndendemoia will be considered following completion of mining activities at Gbeni and Lanti.
The Sembehun deposit, located approximately 30 kilometres from the current Area 1 operations, is one of the largest and highest quality known rutile deposits in the world, presenting an attractive development opportunity, long mine life and additional exploration potential underpinned by strong medium to long term titanium feedstock fundamentals.
Sembehun Phase 1 construction start is schedule on 2024.
Processing
- Electrostatic separation
- Desliming
- Spiral concentrator / separator
- Flotation
- Magnetic separation
Source:
Summary:
During 2019 Iluka completed projects doubling the capacity at both the Lanti and Gangama mining operations in Sierra Leone.
The doubling of capacity of both the Gangama and Lanti dry operations from 500-600 tonne per hour to 1,000-1,200 tonne per hour. [31/06/2019 QREV-Q2, p. 7]
The Gangama project involved the addition of mining fleet and construction of a second concentrator, duplicating the design of existing operations. Commissioning of the Gangama concentrator began in May and was operating at design capacity by June.
At Lanti, a second mining unit was added and the floating concentrator from the decommissioned dredge operation was beached and refurbished. Construction and commissioning activities were completed during August. Both projects were delivered on schedule and on budget.
Concentrator Plants at Lanti: DM1-Commissioned 2013; DM4 - Repurposed concentrator from dredge operations.
Concentrator Plants at Gangama: DM2:1 - C ........

Recoveries & Grades:
Commodity | Parameter | 2021 | 2020 | 2019 | 2018 |
Heavy Minerals
|
Head Grade, %
| ......  | ......  | ......  | 3 |
Heavy Minerals
|
Concentrate Grade, %
| ......  | ......  | ......  | 71.4 |
Rutile
|
Concentrate Grade, %
| ......  | ......  | ......  | 47.7 |
Ilmenite
|
Concentrate Grade, %
| ......  | ......  | ......  | 20 |
Zircon
|
Concentrate Grade, %
| ......  | ......  | ......  | 3.7 |
Reserves at December 31, 2021:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
134 Mt
|
Rutile
|
1.5 %
|
2 Mt
|
Probable
|
78 Mt
|
Rutile
|
1.4 %
|
1.1 Mt
|
Proven & Probable
|
212 Mt
|
Rutile
|
1.5 %
|
3.1 Mt
|
Measured
|
178 Mt
|
Rutile
|
1.4 %
|
2.4 Mt
|
Measured
|
178 Mt
|
Ilmenite
|
0.8 %
|
|
Measured
|
178 Mt
|
Zircon
|
0.1 %
|
|
Indicated
|
309 Mt
|
Rutile
|
1 %
|
3.1 Mt
|
Indicated
|
309 Mt
|
Ilmenite
|
0.6 %
|
|
Indicated
|
309 Mt
|
Zircon
|
0.1 %
|
|
Inferred
|
265 Mt
|
Rutile
|
1 %
|
2.6 Mt
|
Inferred
|
265 Mt
|
Ilmenite
|
0.5 %
|
|
Inferred
|
265 Mt
|
Zircon
|
0.1 %
|
|
Total Resource
|
752 Mt
|
Rutile
|
1.1 %
|
8.1 Mt
|
Total Resource
|
752 Mt
|
Ilmenite
|
0.6 %
|
|
Total Resource
|
752 Mt
|
Zircon
|
0.1 %
|
|
Aerial view:
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