Overview
Stage | Feasibility |
Mine Type | Open Pit / Underground |
Commodities |
|
Mining Method |
- Truck & Shovel / Loader
- Avoca
- Backfill
|
Processing |
|
Mine Life | 13 years (as of Jan 1, 2019) |
The project consists of three open pits, namely Barvue, Abcourt East and Abcourt West, and the development of an underground mine to produce a zinc-silver concentrate. |
Latest News | Additions to the Update on the Abcourt-Barvue Feasibility Study May 2, 2019 |
Source:
p. 28
Summary:
On the Abcourt-Barvue property, the volcanic sequence is represented by the Figuery Group which is bounded to the north by the Amos Group and to the south by the Landrienne Group. The Abcourt-Barvue deposit and related base metal occurrences are located in the Figuery Group.
The Abcourt-Barvue mineralized horizon strikes E-W in the western portion of the property. In the Abcourt shaft area, the mineralized horizon changes its strike from E-W to SE-NW in the Barvue portion of the deposit. On the property, the units have steep (75°) dips to the north with a well-developed E-W regional schistosity. The stratigraphic tops for these units have been documented in the field as being to the north.
The Abcourt-Barvue mineralized zone has a thickness ranging from 2 to 30 metres. The deposit has a known east-west strike length of 2.2 km. Mineralization has been delineated by diamond drilling to a maximum vertical depth of 425 m below the surface. Mineralized horizons are dipping at 75° to the north.
Zinc and silver are the main metallic constituents of the Abcourt-Barvue deposit and these metals are associated with sphalerite, native silver and argentite. The presence of some gold and copper has been observed. Gold is usually associated with silver and copper occurs mostly at the eastern limit of the Barvue deposit.
The main mineralization which is mostly made up of disseminated and bedded sphalerite and pyrite (up to 10% of the rock) is described as:
- iron-poor, honey brown and dark colour sphalerite (ZnFeS2), finely disseminated in the tuff agglomerate horizons concentrated generally to the north of the marker bed, with additional mineralization in the marker bed and in the shear zone;
- 1-2% disseminated pyrite (some encompassed within the sphalerite);
- minor galena (PbS), chalcopyrite (CuFeS2), native silver (Ag) and proustite (Ag3AsS3).
The thickness of the mineralized horizon tends to increase eastward, most of the sulphides being located in the Barvue area. Generally speaking, we can observe a zinc enrichment in both footwall and hanging walls of the mineralized zone which are generally separated by lower grade marginal material. These two sub-parallel zinc-enriched units are currently known over a total length of 2.2 km to a vertical depth of 600 metres.
The Abcourt-Barvue silver-zinc deposit is classified as disseminated volcanogenic sulphide deposit. It shares numerous similarities with the Mattabi-type volcanogenic sulphide deposit. The zinc and silver sulphides mineralization is composed of disseminated and bedded sphalerite and pyrite found in close association with felsic volcanoclastic rocks.
Mining Methods
- Truck & Shovel / Loader
- Avoca
- Backfill
Summary:
The Abcourt-Barvue measured and indicated resources along the mineralized structure span a distance of 2 230 m (1 080 m west of the shaft in an E-W direction, and 1 150 m east of the shaft in a S49°E direction). The dip is 75° to 90° to the north.
In the Barvue sector, the ore lies in the south wall of the old pit, at its eastern extremity and below the current pit floor (at a depth of 76 m) to a maximum depth of 240 m. The mining proposal for Barvue includes deepening the pit to a depth of 166 m from surface and underground mining of the remaining resource.
In the Abcourt sector it is proposed to mine the upper part of the ore body by open pit to a maximum depth of 72 m. Mining will proceed underground under the pit using the Avoca cut- and-fill method to a depth of 150m to 200m with trackless equipment. Three declines will access the underground operation; the west, the central, and the east decline.
Open pit mining will be carried out using conventional truck and shovel method. Drilling will be performed by in-the-hole production drills. Blasting operations will use an emulsion ANFO (ammonium-nitrate fuel oil) explosive and a non-electric delay initiation system. An hydraulic shovel and a front-end loader will be used to load rigid haulage trucks.
For most of the open pit tonnages, haulage trucks will exit from Abcourt and Barvue pits onto a common haul road approximately 500m west of the mill site. Waste rock will be hauled to three (3) different storage areas. The West waste pad and the East waste pad are located approximately 1.7 km from the East Abcourt and the Barvue pit exits.
Over the first 5 years, open pit mining will occur at a maximum annual production rate of 6 Mt of rock per year of which 650 000 tonnes will be ore and the remaining tonnes will be waste rock and marginal ore.
The following parameters were used to design the open pits:
- Average mineralization dip: 75° to 90° to the north;
- Bench height:
1. Barvue pit: ± 17 m (in two cuts in ore);
2. Abcourt pits: 16 m (in two cuts in ore).
- Individual bench slope: 70° to 90°;
- Inter-ramp slope angle: 60°;
- Berm width: 7.5 – 11.0 m;
- Berm width to overburden slope: 6 m;
- Maximum depth of Barvue pit: 166 m;
- Maximum depth of Abcourt pits: 72 m;
- Ramp width:
1. Barvue and East Abcourt pits 8 m and 16 m;
2. West Abcourt pit 12 m and 19 m.
- Ramp gradient: 10-12 %;
- Density of ore: 3.0 t/m³;
- Density of waste: 2.8 t/m³;
- Slope in overburden: 2.5H:1V.
The underground resource of the Abcourt-Barvue deposit is found generally in the hanging wall of a marker tuff where ground conditions are good. The Avoca cut-and-fill method will be used for the underground production.
From three main declines, cross-cuts will be driven into the ore zone and lateral development will proceed on both sides to the limits of the lenses. Production will start at the bottom of the ore zone with sub-levels developed at 15 to 20 metre vertical intervals. All mining will be trackless.
Jumbos will be used for lateral development. The stopes will be mucked out with remote controlled LHD. Abcourt Mines owns several 8 yard3 and 5 yard3 scooptrams and one 4 yd3 scooptram. The 8 yard3 and 5 yard3 scoops will be used for mucking purposes while the 4 yard3 scoop will be used for servicing. The stopes will be drilled with pneumatic long hole machines. The main declines will be driven with a minus 12% to 15% slope.
Blasting operations will use ANFO explosives. A gel cartridge and nonel detonation system will be used for both development and production purposes. Trucks with 42 tonne loads will tram the ore to the surface.
Fresh air for underground mine ventilation purposes will be pushed through ventilation raises. Mine air will exhaust by the ramps. A manway will be installed in the ventilation raises and serve as a second egress.
The main declines, haulage drifts and access cross-cuts will be 5.5-m wide x 4.5-m high. The sub-drifts in ore will be 4.5-m high over the full width of the ore zone. Each stope will have an access cross-cut on each sub-level. The 1.5-m x 1.5-m slot raises will be drilled with a long hole machine.
The underground production will come from three Avoca cut-and-fill stopes which will be named «west stope», «central stope» and «east stope», and from mine development. The stopes extend over a distance of about 1 125 metres from 5010E on the Abcourt side to 135E on the Barvue side. All the planned ore tonnage is located west of the limit separating Barvue from Abcourt.
Mining will progress from the bottom up. The west and central stopes will start at a depth of about 150 metres and finish in the pit bottom at a depth of about 55 metres. The east stope will start at a depth of about 200 metres and will be completed at a depth of about 65 metres, also in pit bottom. Each stope will typically have two faces in ore, so it will be possible to alternate the drilling, blasting and mucking of ore cycle at one end of the stope with the filling cycle at the other end. The objective is to have a steady flow of muck from each stope.
Flow Sheet:
Summary:
The main process steps for treating the Abcourt and Barvue ores are primary crushing and stockpiling, ore bin, SAG/ball grinding, zinc flotation, and dewatering of a zinc concentrate by thickening and filtration. There is also a pyrite (or sulphide) concentrate produced as the last stage of differential flotation.
Barvue and Abcourt ores are mixed on outside stockpiles located near the crushing facilities. The ore is picked up and carried by a front end loader over a feed hopper equipped with an incline 750 mm (30”) square openings grizzly with the undersize dropping into a lined 75 t hopper. Mixing the ore will regulate the grade fed to the processing plant. The ore is extracted from the feed hopper by a pan vibrating feeder.
The jaw crusher discharges onto a 914 mm (36”) transfer belt conveyor. An electromagnet is located at the head of the transfer belt conveyor to remove tramp metal that might otherwise cause belt damage or block the SAG mill feed chute. T ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Silver
|
Recovery Rate, %
| ......  |
Silver
|
Head Grade, g/t
| 51.8 |
Silver
|
Concentrate Grade, g/t
| ......  |
Zinc
|
Recovery Rate, %
| ......  |
Zinc
|
Head Grade, %
| 2.83 |
Zinc
|
Concentrate Grade, %
| ......  |
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Reserves at December 31, 2018:
Category | OreType | Tonnage | Commodity | Grade |
Proven
|
In-Situ (OP)
|
6,180,510 t
|
Silver
|
39.72 g/t
|
Proven
|
In-Situ (UG)
|
1,169,662 t
|
Silver
|
105.19 g/t
|
Proven
|
Total
|
7,350,172 t
|
Silver
|
50.14 g/t
|
Proven
|
In-Situ (OP)
|
6,180,510 t
|
Zinc
|
2.83 %
|
Proven
|
In-Situ (UG)
|
1,169,662 t
|
Zinc
|
2.87 %
|
Proven
|
Total
|
7,350,172 t
|
Zinc
|
2.84 %
|
Proven
|
In-Situ (OP)
|
6,180,510 t
|
Zinc Equivalent
|
3.61 %
|
Proven
|
In-Situ (UG)
|
1,169,662 t
|
Zinc Equivalent
|
4.93 %
|
Proven
|
Total
|
7,350,172 t
|
Zinc Equivalent
|
3.82 %
|
Probable
|
In-Situ (OP)
|
408,851 t
|
Silver
|
43.01 g/t
|
Probable
|
In-Situ (UG)
|
315,139 t
|
Silver
|
101.61 g/t
|
Probable
|
Total
|
723,990 t
|
Silver
|
68.52 g/t
|
Probable
|
In-Situ (OP)
|
408,851 t
|
Zinc
|
2.36 %
|
Probable
|
In-Situ (UG)
|
315,139 t
|
Zinc
|
3.23 %
|
Probable
|
Total
|
723,990 t
|
Zinc
|
2.74 %
|
Probable
|
In-Situ (OP)
|
408,851 t
|
Zinc Equivalent
|
3.2 %
|
Probable
|
In-Situ (UG)
|
315,139 t
|
Zinc Equivalent
|
5.22 %
|
Probable
|
Total
|
723,990 t
|
Zinc Equivalent
|
4.08 %
|
Proven & Probable
|
In-Situ (OP)
|
6,589,361 t
|
Silver
|
39.93 g/t
|
Proven & Probable
|
In-Situ (UG)
|
1,484,801 t
|
Silver
|
104.43 g/t
|
Proven & Probable
|
Total
|
8,074,162 t
|
Silver
|
51.79 g/t
|
Proven & Probable
|
In-Situ (OP)
|
6,589,361 t
|
Zinc
|
2.8 %
|
Proven & Probable
|
In-Situ (UG)
|
1,484,801 t
|
Zinc
|
2.95 %
|
Proven & Probable
|
Total
|
8,074,162 t
|
Zinc
|
2.83 %
|
Proven & Probable
|
In-Situ (OP)
|
6,589,361 t
|
Zinc Equivalent
|
3.58 %
|
Proven & Probable
|
In-Situ (UG)
|
1,484,801 t
|
Zinc Equivalent
|
4.99 %
|
Proven & Probable
|
Total
|
8,074,162 t
|
Zinc Equivalent
|
3.84 %
|
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