Overview
Status | Care and Maintenance |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Gravity separation
- Carbon in leach (CIL)
- Solvent Extraction & Electrowinning
|
Mining of the Zoroastrian open pit by Excelsior Gold to a depth of about 110 metres below surface produced approximately 55,000 ounces from 810,000 tonnes of ore grading 2g/t Au treated at the Paddington plant and Golden Mile Milling’s Lakewood plant.
Mining was completed in 2017. Exploration drilling continues. |
Latest News | Bardoc Gold ready to transition to producer July 8, 2020 |
Deposit Type
- Breccia pipe / Stockwork
- Sedimentary
Summary:
The deposit occurs on the eastern limb of a narrow NNW trending structure, the Bardoc-Broad Arrow syncline within the Bardoc Tectonic Zone. In this zone the sequence comprises highly deformed fault slice lenses of intercalated Archaean mafic and ultramafic volcanics and metasediments.
Gold mineralisation is predominately hosted within a 300 to 400m wide differentiated dolerite emplaced into the mafic/ultramafic-sediment sequence. The geological setting, structure and style of gold mineralisation show a distinct similarity to that seen at Paddington and the Broad Arrow deposits 12 to 16km to the south.
The Zoroastrian dolerite is thought to be the stratigraphic equivalent of the Paddington dolerite which hosted the 1m+ ounce mine at Paddington itself with both deposits bounded to the west by the Black Flag sediments and to the east by the Mount Corlac ultramafics. Shear zones up to 10m wide containing gold bearing laminated quartz veining (5cm to 1m wide) occur on both contacts.
The Zoroastrian South has been the main focus of drilling since the discovery of the stockwork system within the granophyric unit. Here drilling has been conducted beneath a series of historical shallow workings on narrow quartz veins resulting in the discovery of a large body of gold mineralisation at depth.
The Slug Hill/Breakaway area at Zoroastrian South represents a distinct magnetic/gravity high that appears to be folded (or boundinaged) with closure to the south. Sediments and high magnesium basalts/ultramafics are clearly seen in outcrop but have not been intersected and/or identified in drilling beneath the outcrop. Drilling instead has intersected a differentiated dolerite with a granophyric unit hosting gold mineralisation associated with arsenopyrite rich quartz stockwork/breccia. The magnetic high is instead related to a pyrrhotite rich zone within the dolerite with the gold mineralisation occurring predominately within and adjacent to its margins. 3D modelling suggests that the magnetic zone has a similar 30-40 degree plunge to the north similar to the gold mineralisation.
Summary:
Standard open pit mining methods using an excavator and truck fleet have been are employed, assuming double shifting on a continuous basis. The size of the fleet applied for costing and design works was dependent upon the deposit designation (and thus size) Satellite deposits have had a 85t excavator paired with 40t articulated truck fleet costs and design specifications to them. The excelsior and Zoroastrian deposits have had a 120t excavator paired with 90t truck fleet costs and design specifications to them.
Processing
- Gravity separation
- Carbon in leach (CIL)
- Solvent Extraction & Electrowinning
Source:
Summary:
The processing facility proposed is a I.OMtpa CIL plant specifically designed for the KNGP mineralisation and consists of primary crusher, secondary crusher, ball mill, gravity gold recovery, CIL, carbon elution, electrowinning and smelting circuits to produce gold doré.
Recoveries & Grades:
Commodity | Parameter | 2017 |
Gold
|
Head Grade, g/t
| 2.11 |
Production:
Commodity | Units | 2017 |
Gold
|
oz
| 54,700 |
All production numbers are expressed as metal in doré.
Operational Metrics:
Metrics | 2017 |
Ore tonnes mined
| ......  |
Waste
| ......  |
Stripping / waste ratio
| ......  |
Reserves at December 31, 2017:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
20 kt
|
Gold
|
3.4 g/t
|
2 koz
|
Probable
|
460 kt
|
Gold
|
2.5 g/t
|
37 koz
|
Proven & Probable
|
480 kt
|
Gold
|
2.5 g/t
|
39 koz
|
Measured
|
5,237 kt
|
Gold
|
1.4 g/t
|
237 koz
|
Indicated
|
5,938 kt
|
Gold
|
1.9 g/t
|
355 koz
|
Inferred
|
5,710 kt
|
Gold
|
1.5 g/t
|
279 koz
|
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