Overview
Stage | Restarting |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Mechanized Cut & Fill
- Post Pillar Cut & Fill
- Sub-level stoping
- Avoca
- Sub-level Retreat
- Longitudinal retreat
- Cemented backfill
|
Mine Life | 13 years (as of Jan 1, 2017) |
The Halfmile-Stratmat integrated project is comprised of the Halfmile mine and the advanced exploration stage Stratmat project. |
Source:
p. 4
The Halfmile-Stratmat integrated project consists of two non-contiguous claim blocks, the Halfmile and the Stratmat claim blocks. The Halfmile claim block consists of one mineral title comprising 59 claim units and one mining lease together covering 1,685.5 hectares (ha). Trevali, through Trevali (Maritimes) Ltd., a 100% owned subsidiary of Trevali, has a 100% in the mining lease but only a 61.51% interests in certain claims in the northern portion of the claims underlying the North zone mineralization.
The Stratmat claim block is comprised of 95 contiguous mineral claims units that are 100% held by Trevali (Maritimes) Ltd. The 95 claim units cover a total of 2,079 ha but because the claims overlap the pre-existing Heath Steele lease to the south, the effective area of the property is 1,827 ha.
Contractors
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Summary:
The Halfmile and Stratmat are volcanic massive sulphide (VMS) deposits typical of the Bathurst Mining Camp (BMC). The BMC hosts 45 volcanic-sediment hosted massive sulphide deposits and 95 occurrences, including the world-class Brunswick 12 Mine. BMC deposits formed in a sediment-covered back-arc continental rift during periods when the basin was stratified with a lower anoxic water column. The basin was subsequently intensely deformed and metamorphosed during multiple collisional events related to east-dipping subduction of the basin.
The VMS deposits typically form lenses of polymetallic massive sulphide. Most deposits are zoned vertically and laterally from a high temperature, vent-proximal, copper-polonium bismuth-rich veined and brecciated core to vent-distal zinc-lead-silver-rich hydrothermal sediments. The vent complex is commonly underlain by a highly deformed sulphide stringer zone that extends hundreds of metres beneath deposits and consists of veins and impregnations of sulphides, silicates, and carbonates that cut chloritized and sericitized volcanic and sedimentary rocks.
The sulphide minerals consist of disseminated and massive pyrite-sphalerite-galena and chalcopyrite. The sulphide minerals are fine- to medium-grained, and are coarser than those typically found in deposits of the BMC.
Disseminated mineralization, commonly of economic grade, occurs in the phyllitic sedimentary rocks as well as in the talc layers which locally gra ........

Mining Methods
- Mechanized Cut & Fill
- Post Pillar Cut & Fill
- Sub-level stoping
- Avoca
- Sub-level Retreat
- Longitudinal retreat
- Cemented backfill
Summary:
At Halfmile, all run-of-mine (RoM) material will be mined by underground mining method. Sublevel open stoping (SLOS) and Sublevel Retreat (SLR) will be the main mining methods planned, supplemented by post pillar cut and fill (PPCF) and mechanized cut and fill (MCF) mining for Upper zone where mineralization dip angle is approximately at 39 degrees. All mining methods will employ either cemented or unconsolidated waste rock as backfill. The mine plan includes 92% of RoM tonnes from SLOS/SLR with down holes (up holes for sill pillar recovery) on 20 m sublevels and cemented or unconsolidated waste rock fill, and 8% of RoM tonnes from PPCF/MCF with unconsolidated waste rock and cemented waste rock (sill level stopes only). There is no permanent sill or rib pillar considered for the SLOS/SLR mining. Limited sill pillars were planned only for the two trial mining opened mining fronts.
At Stratmat, RoM material will be mined by underground mining, too, similar to Halfmile underground mining except there is no PPCF/MCF mining method employed. RoM materials will be directly hauled by 45-tonne capacity underground trucks to Stratmat DMS plant for waste separation.
Due to the complex geometry and variability in strike and dip, the development of a tool box of mining methods is recommended in order to maximize extraction of the Stratmat project.
The most of the S1 Deep zone will tend to use transverse Sublevel open stoping (SLOS) supplemented with longi ........

Source:

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Flow Sheet:
Summary:

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Projected Production:
Commodity | Units | LOM |
Zinc
|
kt
| 1,217 |
Lead
|
kt
| ......  |
Copper
|
kt
| ......  |
All production numbers are expressed as concentrate.
Operational Metrics:
Metrics | |
Daily milling capacity
| 3,000 t * |
Annual milling capacity
| 1.12 Mt * |
Tonnes processed, LOM
| 10,219 kt * |
Processing scale, tpd
| 3,000 t |
* According to 2017 study.
Corporate Filings & Presentations:
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