Source:
p. 19
Constantine signed an Option and Joint Venture Agreement (Agreement) with Dowa Metals & Mining Co., Ltd. of Japan (Dowa) on February 1st, 2013. Under the terms of the Agreement, Dowa had the option to earn a 49% interest in the Project by making aggregate expenditures of US$22,000,000 over a four-year period. On January 5th, 2017, the Company announced that Dowa had completed its US$22 million earnin to the Project and had exercised its option to participate as a partner in the Project. A Joint Venture was formed (the Dowa JV) for the purpose of further exploring and developing Project, with Constantine owning a 51% participating interest and Dowa owning a 49% participating interest.
Summary:
The Project hosts two known VMS deposits, the Palmer deposit, which consists of the South Wall and RW Zones, and the newly discovered AG Zone deposit, located three km to the southwest (At the South Wall and RW Zones, six mineralization styles have been identified and are grouped according to dominant mineral assemblages and texture and include: Barite mineralization (Zn-rich), Massive Pyrite Mineralization (Cu-rich), Semi-massive and Stringer-style Mineralization, Massive Pyrrhotite Mineralization, Carbonate Mineralization and Barite-Carbonate Mineralization. At the AG Zone deposit, mineralization consists of Massive and Semi-massive sulfide and barite, and feeder-style stringers and replacement. Four alteration facies are associated with the known mineralized zones and include: Quartz-Pyrite, Muscovite, CarbonateChlorite and Epidote.
The South Wall Zones (SWZI, SWZII-III, SWEMZ) are located on the south-facing, steeply dipping limb of megascopic, deposit-scale anticline, disrupted by recognized thrust faulting, normal faulting and strike-slip faulting. The RW Zones (RW East, RW West, RW Oxide) are located on the north-facing, gently dipping upper limb of the same anticline. The RW Oxide Zone is the near surface equivalent of the RW East Zone where sulfide minerals of massive barite-sulfide mineralization have been oxidized and leached, depleting the zone of copper and zinc and enriching the silver and gold grades. The AG Zone deposit (including the AG Main Lens and AG Footwall Zone) is located three km m to the southwest, on a steep Nunatak between the Saksaia and South Saksaia Glaciers.
Drilling to date has defined a total plunge length of near-continuous South Wall mineralization of 700 m, and a total strike length to 550 m, with exhalative mineralization occurring at more than one stratigraphic level. The RW Zones have been defined over a dip length of 325 m, and a total strike length of 800 m. The new AG Zone deposit has a strike length of 550 m and a vertical extent of 250 m. Reconstruction of the primary depositional environment of the Palmer Deposit (via unfolding and restoration of post-mineralization fault offset) yields a single continuous mineralized system that is over 1.5 km in length. The known zones are open to expansion in multiple directions, and most notably, the thickest mineralized intersection is located at the lower limit of the South Wall drilling done to date.
At the South Wall and RW Zones, six mineralization styles have been identified and are grouped according to dominant mineral assemblages and texture and include: Barite mineralization (Zn-rich), Massive Pyrite Mineralization (Cu-rich), Semi-massive and Stringer-style Mineralization, Massive Pyrrhotite Mineralization, Carbonate Mineralization and Barite-Carbonate Mineralization. At the AG Zone deposit, mineralization consists of Massive and Semi-massive sulfide and barite, and feeder-style stringers and replacement. Four alteration facies are associated with the known mineralized zones and include: Quartz-Pyrite, Muscovite, Carbonate-Chlorite and Epidote.
The South Wall Zones (SWZI, SWZII-III, SWEMZ) are located on the south-facing, steeply dipping limb of megascopic, deposit-scale anticline, disrupted by recognized thrust faulting, normal faulting and strike-slip faulting. The RW Zones (RW East, RW West, RW Oxide) are located on the north-facing, gently dipping upper limb of the same anticline. The RW Oxide Zone is the near surface equivalent of the RW East Zone where sulfide minerals of massive barite-sulfide mineralization have been oxidized and leached, depleting the zone of copper and zinc and enriching the silver and gold grades. The AG Zone deposit (including the AG Main Lens and AG Footwall Zone) is located three km m to the southwest, on a steep Nunatak between the Saksaia and South Saksaia Glaciers.
Drilling to date has defined a total plunge length of near-continuous South Wall mineralization of 700 m, and a total strike length to 550 m, with exhalative mineralization occurring at more than one stratigraphic level. The RW Zones have been defined over a dip length of 325 m, and a total strike length of 800 m. The new AG Zone deposit has a strike length of 550 m and a vertical extent of 250 m. Reconstruction of the primary depositional environment of the Palmer Deposit (via unfolding and restoration of post-mineralization fault offset) yields a single continuous mineralized system that is over 1.5 km in length. The known zones are open to expansion in multiple directions, and most notably, the thickest mineralized intersection is located at the lower limit of the South Wall drilling done to date.
Mining Methods
- Longhole stoping
- Transverse stoping
- Longitudinal stoping
- Paste backfill
Summary:
Longhole stoping was selected for both zones of the Palmer deposit as the principal mining method. In the planned LH stopes, a top and bottom drift delineates the stope and blast holes are drilled between the two sub-levels via a LH drilling machine. The blast holes are loaded with explosives and the stope is blasted. The blasted material is extracted from the bottom drift by conventional and remote mucking with LHDs.
Several variations of LH stoping will be applied at Palmer, specific to the geotechnical and geometric properties of the resource zones.
Transverse Longhole
Where ground conditions are good and the resource average thickness is greater than 8 m but less than 20 m) as is the case with Zone 1 and 2-3 from the Palmer deposit and the SW zone of AG, transverse LH stoping will be used. Transverse LH stopes are mined in a primary/secondary fashion whereby primary stopes are mined and filled with a cemented paste backfill. Transverse LH stoping requires a footwall access to be driven parallel to the resource to provide cross-cut entries evenly spaced along strike. As such, this method requires more non-mineralized development than longitudinal LH stoping but offers higher productivity and selectivity given the ability to mine several high grade stopes at once.
Longitudinal Longhole
Where ground conditions are less favourable and the resource width is less than 8 m, longitudinal LH retreat (LHR) will be used. LHR mining is a variation on sub-level LH stoping where the long axis of the stope is along strike of the mineralized zone. LHR stopes are mined, retreating from the outside-in towards the level access. As LHR stopes are mined, they are simultaneously backfilled. Disadvantages to LHR mining include higher backfill dilution, lower mineral recovery, and limited selectivity and productivity. Advantages include less non-mineralized development.
Stope sub-levels are 5 m W x 5 m H and spaced at 20 m vertical increments. Transverse stopes will be 16 m W x 24 m long (L), while longitudinal stopes will be 12 m W x 18 m L. This produces a typical hanging wall (HW) and footwall (FW) exposure of 16 m W x 20 m H and 18 m W x 20 m H for transverse and longitudinal stopes respectively
The mine production rate is approximately 3,400 t/d once full production is established in year 3. The mineralized material will be crushed underground and transported via the 510 Conveyor Drift to the mill. Mineralized material from the Palmer deposit will be fed into the conveyors via the production pass system; the AG Zone deposit material will be hauled to the production pass in the Palmer deposit.
Material Handling
Mineralized Material
Mucking will be carried out using 10 t LHDs with remote tramming capabilities. Levels with a production pass connection, the mineralized material will be trammed and dumped into the production pass system. Levels that are not connected to the production pass system, will have mineralized material trammed to a re-muck, loaded onto 30 t haul trucks, and hauled and dumped to the nearest production pass. The material will be collected at the loading pocket on the 628 Level, crushed and transported out of the mine via conveyor to the mill for processing.
Waste Material
Development waste rock is classified as one of two types:
* Non-potentially acid generating (NPAG) and
* Potentially acid generation (PAG).
Waste rock will be mucked using 10 t LHDs and will be loaded at cross cuts, into 30 t haul trucks. NPAG waste rock will transported to surface via conveyor. This material will be re-handled by the surface fleet, primarily to construct the TSF, avalanche berms and other earthworks.
PAG waste rock will be dump in empty stopes by an LHD were it will mix with the paste backfill. No PAG rock will remain on surface at the end of mine life.
Once a mining panel has been exhausted, the void will be backfilled with a cemented paste backfill composed of pyrite tails, de-sulfide tails and run of mine waste rock that is potentially acid generating (PAG). Paste backfill originating from pyrite tails will be prioritized for primary stopes. Paste for secondary stopes will be composed of the remaining pyrite tails and supplement with de-sulfide tails. Run of mine PAG will be deposed in any available open void. The remaining de-sulfide tails will be filtered and placed at the tailings storage facility (TSF).
Non-potentially acid generating (NPAG) rock generated from the mine will be used in the construction of site infrastructure and the TSF.
Flow Sheet:
Summary:
Material from the mine will feed a single-stage crushing plant located underground. The crushed product will be conveyed from underground to feed the process plant at a rate of 3,500 t/d producing saleable Cu, Zn and Ba concentrates.
The process plant will include:
- Primary crushing (underground)
- Semi-Autogenous Grinding (SAG) mill operating in open circuit
- Ball mill grinding in reverse closed-circuit with cyclones
- Sequential Cu, Zn, and Ba flotation circuits, each incorporating conventional flotation, regrind for Cu and Zn and three cleaning stages - Py rougher flotation, rougher concentrate dewatering and filtration for paste mixing
- Concentrate dewatering and filtration
- Concentrate storage and load-out facilities, and - Tailings dewatering and filtration for deposition in the filtered tailings facility or paste for underground.
The material from underground from the Palmer deposit at average LOM head grades of 0.81% Cu, ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Copper
|
Head Grade, %
| 0.81 |
Copper
|
Recovery Rate, %
| ......  |
Copper
|
Concentrate Grade, %
| ......  |
Zinc
|
Head Grade, %
| 4.24 |
Zinc
|
Recovery Rate, %
| ......  |
Zinc
|
Concentrate Grade, %
| ......  |
Silver
|
Head Grade, g/t
| 49.6 |
Gold
|
Head Grade, g/t
| 0.33 |
Barite
|
Head Grade, %
| 13.3 |
Barite
|
Recovery Rate, %
| ......  |
Barite
|
Concentrate Grade, %
| ......  |
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Reserves at July 18, 2019:
Category | Tonnage | Commodity | Grade | Contained Metal |
Indicated
|
4,677 kt
|
Copper
|
1.49 %
|
154 M lbs
|
Indicated
|
4,677 kt
|
Zinc
|
5.23 %
|
539 M lbs
|
Indicated
|
4,677 kt
|
Silver
|
30.8 g/t
|
4.6 M oz
|
Indicated
|
4,677 kt
|
Gold
|
0.3 g/t
|
45.1 koz
|
Indicated
|
4,677 kt
|
Barite
|
23.9 %
|
1,118 kt
|
Inferred
|
5,338 kt
|
Copper
|
0.96 %
|
113 M lbs
|
Inferred
|
5,338 kt
|
Zinc
|
5.2 %
|
612 M lbs
|
Inferred
|
5,338 kt
|
Silver
|
29.2 g/t
|
5 M oz
|
Inferred
|
5,338 kt
|
Gold
|
0.28 g/t
|
48.1 koz
|
Inferred
|
5,338 kt
|
Barite
|
22 %
|
1,174 kt
|
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Staff:
Total Workforce | Year |
|
2019
|
Corporate Filings & Presentations:
Document | Year |
...................................
|
2019
|
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News:
- Subscription is required.