Overview
Stage | Feasibility |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
|
Mine Life | 18 years (as of Jan 1, 2017) |
Source:
p. 26
Company | Interest | Ownership |
TanzGraphite (TZ) Ltd.
(operator)
|
|
Direct
|
EcoGraph Ltd.
|
100 %
|
Indirect
|
The tenement is 100% owned by Kibaran’s wholly owned subsidiary TanzGraphite (TZ) Limited.
Kibaran Resources renamed itself “EcoGraph Limited” after its wholly-owned subsidiary EcoGraph at the Annual General Meeting on November 29.
Summary:
The Mahenge Project is hosted within a quartz–feldspar graphitic schist, part of a Neoproterozoic metasediment package, including marble and gneissic units. Two zones of graphitic schist have been mapped, named the Eastern Zone and the Western Zone. Mineralisation is believed to be the product of pre-existing carbonaceous sediments subjected to regional metamorphism induced by a north-south regional thrusting event. The graphitic schists contain between 3% and 25% Total Graphitic Carbon.
There is a high level of confidence in the geological interpretation, based upon lithological and structural logging of diamond drill core, and lithological logging of RC chips. Trenches cut orthogonal to the strike of the geology demonstrated the geometry of the deposit, and clearly showed graphitic mineralisation. Deposit scale geological mapping provide a geological framework for the interpretation. Geophysical models (VTEM) support the geological interpretation.
Drill hole intercept logging and assay results (RC and diamond core), structural interpretations from drill core and geological logs of trenches have formed the basis for the geological nterpretation. Assumptions were made on depth and strike extension of the graphitic schists, using drill hole and trench sample assays as anchor points at depth and at intervals along strike. Geological mapping also support the geological interpretation which supports the Mineral Resource estimate.
No alternative interpretations were considered because the exposed geology in outcrop supports the current interpretation.
Graphitic mineralisation is hosted within graphitic schist, which is mapped along its strike within the license area. Total graphitic carbon is assumed to be likewise continuous with the host rock unit. Metallurgical characteristics, principally flake size, has been observed to be of a consistent nature when observed in outcrop, trench exposure and diamond drill core at numerous locations within the license area.
The graphitic schist is open along strike and down dip in Epanko West. The Epanko East deposit is interpreted to be a recumbent fold, open along strike to the north and south. A sub-vertical shear zone offsets the stratigraphy down dip along the lower fold limb.
The TGC mineralisation domains are contained within the graphitic schist lithological domain.
The quality of Epanko Graphite is driven by two geological aspects, firstly the dominant host gangue mineral is a calc silicate mineral with very little deleterious elements and the Epanko rocks have undergone extremely high metamorphic pressure and temperature creating a very high crystallinity.
Weathering domains representing oxide, transitional and fresh were modelled and were used during grade interpolation to constrain grade interpolation, and were allocated different density values.
Lithological domains representing schists, gneisses and marble were interpreted and modelled.
Major structural features, mainly sub-vertical shears and faults, were modelled and used to assess drill data during preparation of the Mineral Resource estimate.
The Epanko West Mineral Resource estimate is approximately 2,150 m in strike, 250 m in plan width and reaches 450 m depth below surface. The Epanko East Mineral Resource is approximately 320 m in strike, 400 m in plan width and reaches 160 m depth below surface.
Summary:
Mining operations will commence in the Eastern Pit and move to the Western Pit in Year 6 through to the scheduled reserve exhaustion in Year 16. The average LOM strip ratio is expected to be 0.4:1 (waste to ore).
Mining will be undertaken via conventional drill and blast with the fleet comprising of an 80t backhoe excavator and 40t off-highway haul trucks. The BFS is based on a mining contractor scenario.
The Western Deposit consists of mining a strike length of 1,360m along the top of the ridge to a depth of 210m in the south, and the Eastern Deposit sits partially over a hill within a small valley and will be mined to a depth of 125m and the pit will have a strike extent of 350m.
Mining dilution and ore loss factors were applied based on weathering and the expected influence of blasting in these profiles. The mineralisation zones consisting of graphitic schist are up to 75m wide in the Eastern and Western zones.
Geotechnical parameters applied to the designs are based on investigations by George Orr and Associates.
Installation of hydraulic monitoring and depressurisation bores with ongoing geotechnical review will be required to ensure the long term stability of final walls. Minimum mining widths have been considered in the Western pit design.
The optimisation was undertaken using only the Measured and Indicated resource classifications. Inferred resource has been treated as waste. The Ore Reserve has been determined constrained by the detailed pit designs.
The mining infrastructure will consist of the contractor laydown, offices and workshops with haulage roads to access the top of the eastern and western mining areas. All waste will be used in the TSF construction. A low grade dump will be constructed over the life of mine. Infrastructure is not detrimental in determining the Reserve.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Jaw crusher
|
|
|
|
|
Cone crusher
|
|
|
|
|
Ball mill
|
|
|
|
1
|
Rod mill
|
|
|
|
1
|
Summary:
The process plant is based on a crush and grind comminution circuit (two stage crushing circuit with single stage rod mill) followed by rougher flotation. The tailings are reground in a ball mill before they enter the scavenger flotation.
Flow Sheet:
Summary:
The process plant is designed with a throughput capacity of 720ktpa for an average TGC grade of 96% and average annual production of 60ktpa.
Processing will consist of a grinding, flotation and concentrator to produce a high quality graphite concentrate. The process is a proven method for the extraction of the graphene to a concentrate.
The tailings are reground in a ball mill before they enter the scavenger flotation. The rougher and scavenger concentrates are combined and fed into the primary cleaner section, consisting out of polishing mills and cleaner flotation banks. The concentrate is than screened into two size fractions, with subsequent polishing and four stage cleaning applied with no further milling required in the cleaning circuit. Product is then dewatered, dried and screened into saleable size fractions. The flowsheet is optimised for a high yield of large flakes, however it could be easily modified to get higher carbon content by flotation if requi ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Graphite
|
Recovery Rate, %
| 94.7 |
Graphite
|
Head Grade, %
| 8.3 |
Graphite
|
Concentrate Grade, %
| 96 |
Projected Production:
Commodity | Units | Avg. Annual | LOM |
Graphite
|
kt
| 60 | 971 |
All production numbers are expressed as concentrate.
Operational Metrics:
Metrics | |
Stripping / waste ratio
| 0.4 * |
Annual processing rate
| 695,000 t * |
Annual processing capacity
| 720 kt * |
* According to 2017 study.
Reserves at June 21, 2017:
The Ore Reserve has been reported at a 5% cut-off grade.
Mineral Resource Estimate for Epanko Deposit > 8% TGC
Category | Tonnage | Commodity | Grade | Contained Graphite |
Proven
|
5.7 Mt
|
Graphite
|
8.41 %
|
483 kt
|
Probable
|
5.9 Mt
|
Graphite
|
8.23 %
|
488 kt
|
Proven & Probable
|
11.7 Mt
|
Graphite
|
8.32 %
|
971 kt
|
Measured
|
7.5 Mt
|
Graphite
|
9.8 %
|
738.9 kt
|
Indicated
|
12.8 Mt
|
Graphite
|
10 %
|
1,280 kt
|
Inferred
|
10.4 Mt
|
Graphite
|
9.9 %
|
1,031 kt
|
Total Resource
|
30.7 Mt
|
Graphite
|
9.9 %
|
3,050 kt
|
Commodity Production Costs:
| Commodity | Units | Average |
All-in sustaining costs (AISC)
|
Graphite
|
USD
|
572 / *
|
C1 cash costs
|
Graphite
|
USD
|
500 / *
|
Assumed price
|
Graphite
|
USD
|
1,181 / *
|
* According to 2017 study / presentation.
Operating Costs:
| Units | 2017 |
OP mining costs ($/t milled)
|
USD
| 7.93 * |
Processing costs ($/t milled)
|
USD
| ......  |
G&A ($/t milled)
|
USD
| ......  |
* According to 2017 study.
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2017 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
Pre-Production capital costs
|
$M USD
|
......
|
Pre-tax NPV @ 10%
|
$M USD
|
......
|
After-tax NPV @ 10%
|
$M USD
|
......
|
Pre-tax IRR, %
|
|
......
|
After-tax IRR, %
|
|
......
|
Pre-tax payback period, years
|
|
......
|
- Subscription is required.
Mine Management:
Job Title | Name | Profile | Ref. Date |
.......................
|
.......................
|
|
Feb 14, 2021
|
- Subscription is required.
Corporate Filings & Presentations:
- Subscription is required.
- Subscription is required.