Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Gravity separation
- Agitated tank (VAT) leaching
- Concentrate leach
- Carbon in pulp (CIP)
- Carbon adsorption-desorption-recovery (ADR)
- AARL elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 7 years (as of Jan 1, 2018) |
Mine production was stopped on November 6, 2019 due to the attack on buses transporting our employees, contractors and suppliers from the Boungou Mine to the capital of Ouagadougou. The Boungou Mine was put on Care & Maintenance for the rest of the year. On February 6, 2020, SEMAFO announced that the Boungou plant had restarted, processing of the stockpile had begun. As of November 6, 2019, the stockpile held approximately 1.1 million tonnes of ore at an estimated average grade of 3.4 grams per tonne. |
Latest News | Endeavour Restarts Boungou Mine and Begins Realizing Synergies Following SEMAFO Integration October 15, 2020 |
Source:
p. 12
July 1, 2020 /CNW Telbec/ - SEMAFO Inc. (TSX: SMF) (OMX: SMF) ("SEMAFO") is pleased to announce the successful completion of the previously announced plan of arrangement (the "Arrangement") involving SEMAFO and Endeavour Mining Corporation ("Endeavour") effective July 1, 2020. The SEMAFO shares will be delisted from the Nasdaq Stockholm and from the Toronto Stock Exchange.
The mining permit is held by SEMAFO Boungou S.A., a corporation held 90% by SEMAFO and 10% by the Republic of Burkina Faso.
Summary:
The Natougou deposit can be described as a West African shear zone hosted greenstone gold deposit. Gold mineralization is associated with biotite and silica-sericite alteration, along with disseminated sulphides such as pyrrhotite, pyrite and minor arsenopyrite and chalcopyrite with occasional free gold. The mineralization is structurally controlled and is hosted primarily within a large shear zone and its associated alteration.
The main mineralized lode is interpreted as a flat-lying anticlinal shear that outcrops in the southeast and plunges gently to the northwest.
The mineralization has a strike length of approximately 2 km, striking towards a bearing of 315° and an across-strike length of approximately 1 km (towards 045°). The mineralization is gently folded with the fold axis oriented along strike and the limbs dipping gently at approximately 15°.
Mineralization is open across strike to the southwest as well as towards 315°, although the shear zone is relatively deep in these directions. The average true thickness of the mineralization is approximately 4 m. Drilling to the west of the resource area up to the felsic intrusive suggests that the shear zone does not continue within the intrusive. The interpretation of the shear zone was therefore stopped at the intrusive/volcanic contact.
Other minor footwall zones have been identified below the main shear zone. Although the footwall zones appear much less continuous and thinner than the main shear zone, some do contain significant gold mineralization. At the end of the 2015 delineation drilling program a short hole-extension program was completed to test the continuity of the footwall zone that was originally encountered in the central portions of the deposit by hole TPA0556, in which a secondary sheared and altered zone returned 10.23 g/t Au over 2.69 m downhole. Nineteen holes were extended to reach the footwall zone, for a combined total of 371 m. Based on interpretation of the results, 13 additional holes (including the original discovery hole) intersected the footwall zone. The combined results suggests that the footwall zone is on average 1.5 m thick with local high grade results returned of up to 31.98 g/t Au over 2.5 m downhole. The footwall zone is interpreted to be sub-parallel to and approximately 20 m below the main Boungou Shear. To date, the footwall zone has been traced over an area of approximately 300 m along strike by 90 m across strike, and remains open in all directions. The interpretation of this footwall zone was included in the current resource model. Other zones of gold mineralization are believed to exist below the main shear and will be explored by SEMAFO further in 2016.
Two types of alteration are significant with respect to the mineralised shear at Natougou. The two alteration types are locally termed the Boungou pink (BPK) and the Boungou bleached zone (BBZ).
The BPK type is a pink-brown alteration consisting of fine-grained biotite-plagioclase and is generally present over the entire width of the mineralised shear zone. It is the schistosity developed by the alignment of the biotite that gives the mineralised zone the sheared texture.
The BBZ type is a silica-sericite alteration generally developed as a discrete zone over widths of about 1 m within the BPK alteration. Variable amounts of quartz veining, often highly deformed (boudinaged or folded), can be observed within some of the BBZ. Small bands of silica-sericite are also interspersed within the wider zones of BPK alteration.
Summary:
Natougou will be mined using a conventional open pit approach of drilling and blasting ore and waste rock, with material mined by hydraulic excavators loading into off-highway rear dump haul trucks. Near surface rock is highly weathered and may be free-dig. Ore will be hauled to a run-of-mine (ROM) ore pad located adjacent to the ore processing plant or dumped directly into the primary crusher. Waste will be hauled to ex-pit waste rock dumps. Waste rock will be backfilled into the mined-out pit void once mining has progressed to enable sufficient pit void to be available.
The deposit will be mined from three distinct pits, approximately 580 m to 1,800 m long, 300 m to 500 m wide, 50 m to 80 m deep and approximately 50 m to 100 m apart. Haulage ramps will be 20 m wide at a 10% gradient, with ore and waste rock trucks using the same haul ramps.
Processing
- Gravity separation
- Agitated tank (VAT) leaching
- Concentrate leach
- Carbon in pulp (CIP)
- Carbon adsorption-desorption-recovery (ADR)
- AARL elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
The Natougou mineralization is predominantly hosted in quartz veins and a significant quantity of the gold occurs as visible, free gold. Sulphide minerals comprise pyrrhotite, arsenopyrite pyrite, and minor chalcopyrite. The Natougou quartz vein deposit is considered free milling. A significant component of the gold is amenable to gravity recovery and consequently the proposed process facility will consist of the following process areas:
• Primary crushing and coarse ore storage.
• Grinding, utilizing a SAG Mill, Tower Mill and Pebble Crusher (SATMC) circuit.
• Leach and CIP Carousel circuit.
• Gold recovery and carbon handling circuit (consisting of a cold acid wash followed by a split, Anglo American (AARL) elution circuit and horizontal carbon regeneration kiln).
• High density tailings handling and disposal.
The Natougou project process plant will be designed to process 4,000 tpd (1.34 Mtpa) with an average gold head grade of 4.15 g/t.
Recoveries & Grades:
Commodity | Parameter | 2019 | 2018 |
Gold
|
Recovery Rate, %
| ......  | ......  |
Gold
|
Head Grade, g/t
| 6.65 | 5.75 |
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Reserves at December 31, 2019:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
3,230,000 t
|
Gold
|
4.47 g/t
|
464,000 oz
|
Probable
|
7,068,000 t
|
Gold
|
3.38 g/t
|
769,000 oz
|
Proven & Probable
|
10,298,000 t
|
Gold
|
3.72 g/t
|
1,233,000 oz
|
Measured
|
502,000 t
|
Gold
|
4.11 g/t
|
66,000 oz
|
Indicated
|
5,281,000 t
|
Gold
|
3.16 g/t
|
537,000 oz
|
Measured & Indicated
|
5,783,000 t
|
Gold
|
3.25 g/t
|
603,000 oz
|
Inferred
|
1,318,000 t
|
Gold
|
2.98 g/t
|
126,000 oz
|
Aerial view:
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