Overview
Stage | Preliminary Economic Assessment |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Smelting
- Intensive Cyanidation Reactor (ICR)
- Carbon re-activation kiln
- Centrifugal concentrator
- Dewatering
- Electric furnace
- Gravity separation
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- AARL elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 12 years (as of Jan 1, 2020) |
The combination of the Golden Highway gold deposits with the Garrison gold deposits has resulted in the creation of a large gold development project - the Tower Gold Project |
Latest News | Moneta Intersects Significant Gold Mineralization in Step-out Drilling at Garrcon, Tower Gold Project March 24, 2022 |
Source:
p. 4
Moneta acquired 100% of Northern Gold, a private company from O3 Mining in February 2021. Northern Gold holds the Golden Bear assets in the eastern Timmins Camp area, includes the Garrison gold project.
Deposit Type
- Breccia pipe / Stockwork
- Vein / narrow vein
- Magmatic
- Syenite hosted
Summary:
Garrcon Deposit
The Garrcon deposit, located at UTM coordinates 5,374,000N and 579,000E, comprises a broad zone of low-grade gold mineralization that includes local higher-grade areas. It occurs within the Timiskaming Assemblage adjacent and to and north of the Porcupine-Destor fault and to the east of the north-south trending Garrison fault. It is a zone of brecciated, silicified metasediments with stockwork type quartz-carbonate veins and veinlets and minor disseminated sulphides cut by narrow variably altered lamprophyre and syenite dikes. Preliminary metallurgical testwork indicates that the Garrcon mineralization is non-refractory and free milling.
Host Rocks, Structures, Mineralization & Alteration Gold mineralization in the Garrcon metasedimentary zones is hosted by Timiskaming-age metasedimentary rock sequences that include greywacke, arkose and iron formation cut by narrow lamprophyre and syenite dikes, occurring adjacent to the Destor-Porcupine Fault Zone These metasedimentary sequences have been hydrothermally altered and mineralized in distinct zones persisting to depths greater than 650 m vertically. The intrusive dikes are variably altered. Gold occurs in a complex system of stockwork veins hosted in a zone of brecciated and silicified metasediments.
The sedimentary package shows little variation, mainly including fine to coarse-grained sandstones as well as minor mudstone layers. The veins are composed predominately of quartz-carbonate (calcite, dolomite and ankerite) with and without albite. The stockwork veins are normally less than one centimetre in width with many being only a half centimetre wide or less.
Gold occurs primarily as native gold within the stockwork veins with minor dissemination into the vein walls. Higher grade intersections (above 10 g/t) are frequently intersected in intervals where pyrite makes up much less than 1% of the total rock. The principal minerals are native gold, pyrite, magnetite, specularite and pyrrhotite with subordinate chalcopyrite, sphalerite, galena and arsenopyrite. Pervasive wall rock alteration is common adjacent to the veins, usually consisting of carbonatization (ankerite or ferroan dolomite) and minor sulphides (pyrite and pyrrhotite).
Length, Width, Depth & Continuity of Mineralization
Development and mining at the Garrcon Shaft Zone began in 1935 with the sinking of a 256 ft (78 m) deep shaft by Consolidated Mining and Smelting Company of Canada Ltd. In 1986, diamond drilling by Cominco Ltd. delineated two new auriferous zones (the North and South Zones) which were described as "stratabound". The South Zone was reported to be hosted by altered sedimentary rocks, with mineralization averaging 1.8 m in width, and traced by diamond drilling to 500 ft (152 m) vertical along 396 m of strike length. The South Zone is described by Bath (1990) as striking 75°, dipping south at 50° and within about 21 m of and/or within a regional scale, east-striking and steeply dipping shear developed between clastic sedimentary rocks to the north and komatiitic rocks to the south. The North Zone was reported to be hosted in a shear zone, and had been traced along strike for about 61 m, down to 152 m in the vertical, and averaged 3.3 m in width.
The lithology used for the deposit model is similar to that developed by Rockridge for the 2019 resource estimate and was developed around a pervasive metasedimentary unit located between the Munro and Porcupine-Destor fault zones and to the east of the Garrison fault. Mineralized domains bounded by faults lie within a broad zone of high and lower grade mineralization that extends over an east-west distance of 2,400 m.
Jonpol Deposit
The Jonpol deposit, located at UTM coordinates 5,374,100N and 577,300E, was the primary exploration target on the property in the 1980s and 1990s. In 2013, Northern Gold renewed exploration on the Jonpol deposit. In 2016, Osisko drilled 17,952.45 m targeting the Jonpol Zone, including 25 holes drilled in the Garrcon and 903 Zones which intercepted the Jonpol Zone at depth.
Host Rocks, Structures Mineralization & Alteration
The Jonpol deposit is a zone of gold mineralization hosted in structurally controlled alteration zones within mafic to ultramafic (tholeiitic to komatiitic) rocks along the north contact of the Munro Fault, which crosses the north-central part of the property. Jonpol gold mineralization is generally associated with pervasive carbonate alteration with late stage silicification, sulphidization (pyrite and arsenopyrite) and sericitization, giving the altered rock a pale beige to pale purple-grey hue.
Length, Width, Depth & Continuity of Mineralization
Previously, the Jonpol deposit was modelled as four contiguous mineralized zones (JD, JP, RP and East Zone), along the Munro Fault, which is a splay from the regional Porcupine-Destor Fault. RockRidge consolidated the Jonpol deposit into three contiguous structurally bounded zones: west of the Garrison Fault, immediately east of the Garrison, and Far East. The mineralized structures strike approximately 070° (true north) and dip steeply to the south. The Jonpol deposit has a combined strike length of 2,000 m. The mineralized structures have been intersected from surface to a maximum vertical depth of approximately 750 m below surface. True widths of mineralized structures vary from 1.5 m to greater than 10 m. The zones remain open at depth.
903 Deposit
The 903 Zone, located at UTM coordinates 5,373,200N and 577,200E, was drill tested by previous operators in the mid-1940s and late 1980s. In 2013, Northern Gold renewed exploration at the 903 Zone. Osisko focused its 2016 to 2018 drilling campaign on expanding the 903 Zone. A total of 87,251 m was drilled in 2016 to 2018, of which 57,404 m were from the 903 Zone.
Host Rocks, Structures Mineralization & Alteration
Extensive drilling by Osisko in 2016 to 2018 has helped classify the mineralization style at the 903 deposit as primarily a traditional “syenite associated deposit”. Although no geochronology has been conducted, the syenites are likely associated with the Timiskaming magmatic event, recognized along the Abitibi, with alkaline characteristics, which occurred approximately between 2,680 and 2,672 Ma (Corfu et al, 2001). Host rocks consist of albite-sericite-chlorite altered ultramafic to mafic volcanics, and alteration primarily albite-hematite-specularite.
Length, Width, Depth & Continuity of Mineralization
Fractured and/or pyritic and/or quartz vein bearing syenite dikes within the 903 deposit are anomalously auriferous along significant core lengths (ranging from about 30 cm to about 10 m). Historic and current drilling has traced the zone along 1,840 m of strike length. The zone remains open at depth and along strike.
Summary:
Open pit mine designs, mine production schedules and mine capital and operating costs have been developed for the 903 Zone, Jonpol and Garrcon deposits at a scoping level of engineering. The mineral resources form the basis of the mine planning. The open pit operations are designed for approximately 12 years of operation. Mine planning is based on conventional open pit methods suited for the project location and local site requirements.
Ultimate pit limits are split up into phases or pushbacks to target higher economic margin material earlier in the mine life. The 903 deposit is split into three phases; the Jonpol deposit is split into two phases; and the Garrcon deposit is split into three phases: two in the main zone and one in the northeast zone. Pit designs are based on Pseudoflow algorithm developed 3D shells with overall slope angles of 40° in bedrock and 25° in overburden. Detailed pit configurations with benching and ramps have not been carried out. Chosen phase shell targets have room for these details to be added in future planning and modifications to pit contents are not expected to be materially altered.
The mill will be fed with material from the pits at an average rate of 4.0 Mt/a (11 kt/d). Cutoff grade optimization is employed that results in a low-grade stockpile east of the 903 deposit and is planned for reclamation to the mill in the later years of the mine life. Overburden will be placed in stockpiles throughout the property. Waste rock will be placed in stockpiles adjacent to all pits.
Owner-operated mining operations will be based on 365 operating days per year with two 12- hour shifts per day. An allowance of 10 days of no mine production has been built into the mine schedule to allow for adverse weather conditions.
The mining fleet will include diesel-powered down the hole (DTH) drills with 165 mm bit size for production drilling, diesel-powered reverse circulation (RC) drills for bench-scale grade control drilling, 12 m3 bucket size diesel-hydraulic excavators and 13 m3 bucket sized wheel loaders for production loading, and 91 t payload rigid-frame haul trucks and 36 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 feeding ex-pit settling ponds. All surface water and precipitation in the pits will be removed via diesel-powered centrifugal pumps. The mine equipment fleet is planned to be purchased via a lease financing arrangement.
Owner-operated maintenance on mine equipment will be performed in the field with major repairs to mobile equipment in the shops located near the plant facilities.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Jaw crusher
|
|
|
|
1
|
Cone crusher
|
|
|
|
1
|
SAG mill
|
|
|
|
1
|
Ball mill
|
|
|
|
1
|
Summary:
Primary Crushing & Stockpiling
Material is hauled from the mine and direct tipped into to the crusher feed hopper. Material from the feed hopper is discharged to a vibrating grizzly screen where undersize is conveyed to the crushed ore stockpile and oversize is discharged to the primary crushing jaw crusher. Material is broken up by the jaw crusher along with a mounted rock breaker. The crushed material is conveyed to a covered stockpile that provides approximately 16 hours of live storage. The residence time of the stockpile permits opportunity to perform maintenance on the crushing circuit without affecting the process plant.
Crushed material is withdrawn from the stockpile by two apron feeders that discharge onto the SAG mill feed conveyor. Oversize pebbles from the SAG mill are fed to a recycle circuit via conveyors. Pebbles are crushed by a cone crusher and discharged on the SAG mill feed conveyor to recycle to the SAG mill.
Grinding Circuit
The grinding circuit consists of a SAG mill with pebble crushing, and is followed by a ball mill in closed circuit with a hydrocyclone cluster. The SAG mill is operated in closed circuit where SAG mill product is discharged into a closed ball mill circuit, and SAG mill trommel oversize feeds a pebble crusher which assists in the size reduction harder pieces of ore. This type of grinding circuit is known as a SAG ball mill, crusher (SABC) grinding circuit.
The ball mill circuit starts at the cyclone feed pumpbox where SAG mill product and ball mill product is discharged. Slurry entering the pumpbox is pumped up to a hydrocyclone cluster as well as a gravity circuit via separate pumps. The hydrocyclones classify the ore based on particle size required for leaching. Optimal leaching of the Garrison deposit is at a grind of 80% passing size of 75 µm. Cyclone overflow gravitates over the trash screen. Trash screen oversize is collected in a bunker and periodically removed. Trash screen undersize reports to the leach/CIL circuit. The hydrocyclone underflow containing larger particles returns to the ball mill for further size reduction, the circulating load within the ball mill hydrocyclone circuit is expected to be 350%. Water is added to the cyclone feed pumpbox to obtain the required cyclone feed density.
Processing
- Smelting
- Intensive Cyanidation Reactor (ICR)
- Carbon re-activation kiln
- Centrifugal concentrator
- Dewatering
- Electric furnace
- Gravity separation
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- AARL elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
The process design includes the following:
• primary crushing of run-of-mine (ROM) material
• covered crushed material stockpile to provide buffer capacity for the process plant
• SAG mill with trommel screen in closed circuit with a pebble crusher, followed by a ball mill with cyclone classification
• gravity recovery of ball mill discharge by one semi-batch centrifugal gravity concentrator, followed by intensive cyanidation of the gravity concentrate and electrowinning of the pregnant leach solution.
• trash screening
• pre-aeration, leach and carbon-in-leach adsorption
• acid washing of loaded carbon and Anglo-American Research Laboratory (AARL) type elution followed by electrowinning and smelting to produce doré
• carbon regeneration
• cyanide destruction of tailings using SO2/air process
• carbon safety screening, and tailings disposal
• reagent storage and distribution
• water services (process w ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Gold
|
Recovery Rate, %
| 92.4 |
Gold
|
Head Grade, g/t
| 0.9 |
Reserves at November 25, 2020:
The base case cut-off grade is 0.30 g/t Au.
Category | Tonnage | Commodity | Grade | Contained Metal |
Indicated
|
66,268 kt
|
Gold
|
0.855 g/t
|
1,822 koz
|
Inferred
|
45,337 kt
|
Gold
|
0.729 g/t
|
1,062 koz
|
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