Source:
p. 56
Atlantic Gold Corp through its indirectly wholly-owned subsidiary Atlantic Mining NS Corp. (formerly DDV Gold Ltd) has a 100% interest in the Cochrane Hill project.
Atlantic Gold Corporation was acquired by St Barbara Limited on July 19, 2019.
Summary:
Individual mining operations, including mining at Cochrane Hill, have focussed on quartz-vein hosted gold deposits within the Goldenville Formation, typically associated with the limbs and hinges of anticlines. This setting is often referred to as ‘Meguma style’ gold mineralization and a number of workers have drawn parallels with a similar style of gold mineralization in the Victorian Goldfields of eastern Australia (e.g. Christie et al, 1999) .
At Cochrane Hill, the highest gold grades are typically associated with bedding-parallel tabular quartz veins. However, the host rock material between quartz veins also carrie s significant gold grades. It is the quartz vein hosted gold mineralization augmented by dissem inated style mineralization that forms the basis of a geological model associated with the ongoing exploration and development of the Cochrane Hill Deposit.
Gold mineralisation within the Cochrane Hill Property has been recognised over a strike length of approximately 3.8km, along a single trend, several hundred metres south of the a nticlinal axis.
The Cochrane Hill Deposit is near the eastern end of this trend. It occurs as a tabular zone of parallel, planar quartz veins in a well bedded argillite and greywacke protolith, dipping steeply to the north at approximately 70°, parallel to bedding in the southern limb of the overturned Cochrane Hill Anticline. Gold mineralisation occurs over true widths of up to 60m to 70m, within which better grade material (eg, +0.8g/ t) is persistent over true widths varying from 5m to 30m. The base of the gold mineralisation is relatively sharp in terms of grade but the hanging wall contact is less defined, with an erratic distribution of weakly anomalous grades and occasional +1g/ t Au grades. The mineralisation has been d efined over a strike length of 1500m and down to a vertical depth of up to 250m.
There appears to be very little disruption of the mineralised zone by post mineralisation faulting, a minor exception being a series of thin faults or shears striking at 110° to 130° relative to grid (101° to 121° relative to true north).
The gold mineralisation in the Cochrane Hill Deposit occurs both within the quartz veins and within the biotite schist (after argillite) and metagreywacke host rock, in association with sulphides, particularly arsenopyrite, pyrite and pyrrhotite but also with traces of base metal sulphides particularly galena and sphalerite. The arsenopyrite occurs as porphyroblasts to 1cm diameter and more and as thin lenses or stringers of sulphide aggregates with pyrite and pyrrhotite, aligned with cleavage which in turn, is aligned with bedding and quartz veining.
Summary:
Mining is based on conventional open pit methods suited for the project location and local site requirements. The mining fleet will include diesel powered down the hole (DTH) drills with 144 mm bit size for production drilling, diesel-powered RC drills for bench- scale grade control drilling, 5 m3 bucket size diesel hydraulic excavators and 7 m3 bucket sized wheel loaders for production loading, and 64 t payload rigid-frame haul trucks and 41 t articulated trucks for production hauling, plus ancillary and service equipment to support the mining operations. In-pit dewatering systems will be established for each pit. All surface water and precipitation in the pits will be handled by submersible pumps.
Mine operations will continue at Touquoy and will move to Beaver Dam once the Touquoy open pit is exhausted in 2023.
Two independent stand-alone open pit operations at Fifteen Mile Stream and Cochrane Hill will run concurrently with the Touquoy and Beaver Dam operations.
At Cochrane Hill, ore will be hauled to a crusher to be situated 1,200 m east of the pit, which will feed the process plant. Waste rock will be split into PAG and NPAG material and will be deposited into a WRSFs to be located 700 m north of the pit or will be used as rock fill in construction of the TMF that will be situated 1,300 m southeast of the pit.
The Cochrane Hill pit is split into south and north phases with the higher-grade south phase mined ahead of the north phase. A starter phase is also designed to provide waste rock construction materials to the starter tailings dam. Starting in 2022 an eight-year mine production schedule is developed.
Processing
- Gravity separation
- Flotation
Flow Sheet:
Summary:
A process facility with a nominal treatment rate of 2.0 Mt/a has been designed to recover and concentrate gold from ore mined at the Cochrane Hill open pit. The plant will operate two shifts per day, 365 d/a at an overall plant availability of 92%. The process plant will produce a gold concentrate to be transported and further treated at the Touquoy process plant.
Run of mine ore will be hauled from the open pit to a crushing facility that includes a jaw crusher as the primary stage and cone crushers for secondary and tertiary size reduction.
Crushed ore will be ground by a ball mill in a closed circuit with cyclones. The primary cyclone overflow, with P80 of 350 µm will be forwarded to a secondary cyclone cluster where a fines fraction (less than 150 µm) and coarse fraction (over 150 µm) will be separated. Centrifugal gravity separation units will be installed to obtain GRG from the primary cyclone underflow stream. The fines fraction (-150 µm) reports to conven ........

Combined production numbers are reported under
Moose River Consolidated (MRC) Operation
Operational Metrics:
Metrics | |
Stripping / waste ratio
| ......  |
Waste tonnes, LOM
| ......  |
Ore tonnes mined, LOM
| ......  |
Tonnes milled, LOM
| ......  |
* According to 2019 study.
- Subscription is required.
Reserves at February 15, 2019:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
10.25 Mt
|
Gold
|
1.08 g/t
|
|
Probable
|
5.13 Mt
|
Gold
|
0.96 g/t
|
|
Measured
|
10.78 Mt
|
Gold
|
1.12 g/t
|
387.3 koz
|
Indicated
|
6.67 Mt
|
Gold
|
1.02 g/t
|
219.2 koz
|
Measured & Indicated
|
17.45 Mt
|
Gold
|
1.08 g/t
|
606.5 koz
|
Inferred
|
1.82 Mt
|
Gold
|
1.24 g/t
|
72.7 koz
|
Commodity Production Costs:
| Commodity | Units | Average |
Assumed price
|
Gold
|
USD
|
...... *
|
* According to 2019 study / presentation.
- Subscription is required.
Operating Costs:
| Units | 2019 |
OP mining costs ($/t milled)
|
CAD
| 11.8 * |
Processing costs ($/t milled)
|
CAD
| ......  |
Total operating costs ($/t milled)
|
CAD
| ......  |
* According to 2019 study.
- Subscription is required.
2019 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
Pre-Production capital costs
|
$M CAD
|
......
|
Sustaining CapEx
|
$M CAD
|
......
|
- Subscription is required.
Mine Management:
Job Title | Name | Profile | Ref. Date |
.......................
|
.......................
|
|
Jan 17, 2020
|
- Subscription is required.
Corporate Filings & Presentations:
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News:
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