Source:
p. 16
East Africa Metals Inc. (EAM) through its wholly-owned subsidiary Tigray Resources Inc. (TRI), holds a 70% interest in the Harvest Project, which includes the Terakimti oxide and volcanogenic massive sulphide (VMS) deposit (the Terakimti oxide deposit or the Terakimti Gold Heap Leach Project). The remaining 30% ownership is held by Ezana Mining Development (Ezana), a private Ethiopian company.
Summary:
The geology proximal to the Terakimti deposit comprises a northeast trending, central belt of intermediate porphyritic metavolcanic rocks flanked to the north by Neoproterozoic metasedimentary rock and granodiorite, and to the south by intermediate to mafic volcanic rocks. Significant chlorite, sericite, and silica alteration is associated with conformable gossanous horizons associated with the contact area of the intermediate and felsic volcanic rock packages, quartz-eye volcanic rocks and intrusive rocks are also present in this altered zone. The gossans are associated with polymetallic massive sulphide (gold- silver-copper-lead-zinc) mineralization at depth. Magnetic cherts are noted in the gossan area. The rocks have been affected by intense deformation, resulting in the development of a penetrative fabric in all lithologies, but in particular those rich in sericite. Local folding is present, but large- scale folds have not been identified.
The largest known economic occurrence on the Harvest property is the Terakimti deposit, a Neoproterozoic volcanogenic hosted massive sulphide discovery. Extensive drilling at 40 m by 40 m to 40 m by 80 m drill spacings (20 m by 20 m in oxide), it is currently defined as a moderate-sized relatively high-grade copper- gold-silver-zinc-lead occurrence containing multiple stacked lenses over 800 m strike and defined to depths f at least 260 m below surface. It is hosted within a bimodal volcanic sequence of intermediate and mafic volcanic (including pillow basalt) to volcanoclastic rocks. Numerous quartz-eye porphyry dykes intrude the centre of the mineralized system but the timing relationship is unclear (coeval to postdating mineralization). The VHMS is interpreted to be located along a syn- sedimentary fault, reactivated during regional compression, which cross cuts stratigraphy. The fault zone is defined in surface mapping as a zone of shearing and brittle faulting further northeast. In section, the interpreted fault zone includes sulphide breccia, porphyry and aplite dykes, jasperoid alteration of host rocks and laminated ore types.
Mineralization along the fault zone dips southeast at 40° to 90° and plunging at 20° to 40° degrees toward 073° to 090°. Bedding in the surrounding rocks generally dips 40° to the east, with open to tight folding observed. The Terakimti VHMS is interpreted to lie on the west limb of a regional tight syncline.
The Terakimti VHMS system consists of at least four stacked lenses containing coppergold- silver and variable zinc-lead:
• The Southern Lens is up to 50 m in true thickness, at least 360 m in strike, and up to 170 m high. It has a massive pyrite base up to 5 m thick and is a mound shaped lens. It is significantly supergene affected (upgraded) at the southern end of the north-northeast plunging Terakimti System. The peak primary sulphide intercept includes 73.85 m. The Southern Lode consists of massive fine-grained pyrite, with coarser grained chalcopyrite and lesser sphalerite as interstitial fill, pyrite replacement and fracture fill. Its average density is 4.07 (SG), including barren thin felsic intervals. It plunges at 20 to 45°.
• The Central Lens sits structurally above and flanks the Southern Lens, is up to 150 m high (dip component), up to 15 m in true width (averages 8 to 10 m) and is currently defined over 480 m down plunge (open down plunge). This lens is well banded in places, somewhat tabular and reasonably predictable. The Central Lens is directly overlain by the hanging wall basalt, which is carbonate and jasperoid altered near sulphide mineralization. The peak diamond drillhole intercept is 15.2 m. The peak reverse circulation oxide intercept is 33.0 m. The Lens has a shallow plunge in the southwest, steepening down plunge to the northeast and is roughly capped by the central porphyry intrusion. It is interpreted to lie within the main fault in the southwest and is located proximal to the main fault in the northeast.
• The Northern Lens is separated from the Southern Lens by a porphyry dyke swarm but the two lenses were unlikely to have joined. The northern lens is open down dip and plunge, strikes for at least 400 m, is up to 20 m true thickness and has a maximum down dip extent of 120 m thus far defined. This lens is also slightly banded and yields very high-grade gold gossans in the oxide zone above the main high- grade shoot. Peak results from primary sulphide include 20.85 m.
• A Lower Zinc Lens, has been intersected in several drill holes over a strike of 400 m with a vertical height of 30 m and is up to 10 m thick (overall cigar shaped lens). Very high- grade zinc occurs over 3.5 m. This lens is interpreted to be on a separate structure to the east of the Central, Southern and Northern Lenses. The mineralization is typically brecciated with jasperoidal alteration and porphyry dykes intruding along the structure.
The near-surface part of the Terakimti system has been affected by supergene processes with distinctive vertical mineral zonation developed. These are:
• Surficial gold enriched Oxide Zone (gossan). Gold is enriched with little to no sulphide, minor to no copper, zinc or silver and elevated lead. There may be a weak leached zone before the transition.
• Silver Enriched Transition Zone with variable gold. Pyrite remains but no other primary ore minerals are present. There is weak copper as covellite, pyrite, high gold and high silver (300 g/t gold).
• The Supergene Copper Zone which is largely primary with 5 to 20% secondary minerals (mainly covellite, minor chalcocite) with chalcopyrite present. Sphalerite locally remains and only chalcopyrite is significantly affected.
• Primary Zone of which there are several different lenses with different characteristics. The main lenses are massive to sub-massive fine-grained pyrite with overprinting, interstitial and fracture-related chalcopyrite and low-iron sphalerite, with gold and silver (rarely galena) in pyrite or as banded sulphide layers and occasional high- grade stringer zones.
Summary:
An open pit mine plan has been completed for the Terakimti Oxide Project.
The PEA open pit contains the following oxide resources:
• 1,086 kt of potential mill feed
• 4,093 kt of waste rock (including mineralized material below cut-off grade)
• 110,000 tr oz of gold
• 799,000 tr oz of silver.
The pit shape follows the outcropping mineralised zone in a northeast-southwest orientation. The final pit designed for the PEA has three access areas, two on the eastern side of the pit as the main access from the process facility and one on the western side of the pit, which will be used for delivering waste to the WRD.
The Mineral Resource will be ripped where possible and with blasting expected to be required beyond a shallow free digging depth.
Hydraulic excavators (backhoe) and wheeled loaders will be used to load ore into trucks. The trucks will haul the material to a crusher on the south-east side of the pit. After crushing, the material will be loaded into a haul truck and transported to the heap leach facility.
Waste rock will be ripped where possible or blasted. Broken waste rock will be loaded into haul trucks and transported to an engineered WRD structure located approximately 120 m northwest of the pit.
This PEA considers open pit mining of the Terakimti deposit oxide zone. Mining will commence with stripping and stockpiling of topsoil and overburden, which will subsequently be used for rehabilitation of the mine site after mining, is complete.
After stripping of topsoil and overburden, an initial zone of softer rock is expected to be amenable to free digging or ripping. Currently it is expected that as the pit deepens drill and blast would be required. Site geologists and mine planning personnel will demarcate mineralized material prior to excavation. Waste rock will be stored at the WRD. Heap leach feed will be transported to the crusher for sizing prior to transport to the heap leach pad.
Mining will be conducted on 5 m benches and will incorporate the concept of staged push backs to minimize and delay increases in waste stripping until required.
Mine planning personnel will plan the mining tactics, including ensuring the timely prestripping of waste material to expose ore. Mining will be planned to achieve the average of 250,000 t/a of heap leach material. However, it is expected that daily tonnage from the mine will fluctuate and as such a stockpile may be used to ensure consistent feed to the crusher and subsequent heap leach during operations.
Processing
- Heap leach
- Merrill–Crowe
- Cyanide (reagent)
Flow Sheet:
Summary:
The processing facilities proposed for Terakimti include:
- two-stage crushing, screening, and agglomeration;
- heap stacking and leaching;
- gold and silver recovery by Merrill Crowe processing.
The heap leach has been designed to process 260 kt/a of oxide tailings. This would be equivalent to a throughput rate of 715 t/d. The crushing/leaching/gold recovery will operate 24 hours per day, seven days per week. The material that has been stacked on the heap leach pad will be continuously leached year- round. The availabilities will be 70% for the crushing and agglomeration circuits and 90% for the leaching and Merrill Crowe treatment circuits to allow for planned downtimes, such as maintenances, shift changes, and unplanned downtimes.
CRUSHING
A two-stage crushing circuit has been proposed to reduce the run-of-mine (ROM) oxide material to finer than 20 mm. The crushing circuit will include a jaw crusher, a vibrating screen, a cone crusher, an ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Gold
|
Recovery Rate, %
| ......  |
Gold
|
Head Grade, g/t
| 3.14 |
Silver
|
Recovery Rate, %
| ......  |
Silver
|
Head Grade, g/t
| 22.9 |
- Subscription is required.
Reserves at October 18, 2015:
Category | Tonnage | Commodity | Grade | Contained Metal |
Indicated
|
1,110,000 t
|
Gold
|
3.2 g/t
|
114,000 oz
|
Indicated
|
1,110,000 t
|
Silver
|
23.6 g/t
|
841,000 oz
|
Indicated
|
1,110,000 t
|
Copper
|
0.08 %
|
|
Indicated
|
1,110,000 t
|
Gold Equivalent
|
3.41 g/t
|
|
Inferred
|
15,000 t
|
Gold
|
1.94 g/t
|
1,000 oz
|
Inferred
|
15,000 t
|
Silver
|
13.5 g/t
|
7,000 oz
|
Inferred
|
15,000 t
|
Copper
|
0.04 %
|
|
Inferred
|
15,000 t
|
Gold Equivalent
|
2.06 g/t
|
|
- Subscription is required.
Staff:
Employees | Total Workforce | Year |
|
|
2018
|
Corporate Filings & Presentations:
Document | Year |
...................................
|
2018
|
- Subscription is required.
News:
Aerial view:
- Subscription is required.