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THUNDER BAY, ON, Nov. 10, 2021 /CNW/ - Clean Air Metals Inc. ("Company") is pleased to announce that it has made the final payment of CAD$1 Million, for and on behalf of Benton Resources Inc. ("Benton"), directly to Rio Tinto Exploration Canada Inc. ("RTEC"), pursuant to the terms of the definitive option agreement (the "Option Agreement") entered into by the Company and Benton in order to satisfy a payment requirement of Benton under its pre-existing option agreement with RTEC dated October 9, 2019 relating to the Escape Lake Property.
Clean Air Metals has now fulfilled all of Benton's payment obligations under the Escape Lake Option Agreement, earning Benton a 100% right, title and interest in and to the Escape Lake Property, subject a 1.0% net smelter return royalty to be retained by RTEC, and subject to Clean Air Metals' right to acquire 100% of Benton's interest in and to the Escape Lake Property pursuant to the terms of the Option Agreement.
Deposit Type
- Magmatic
- MMS
- Intrusion related
- Vein / narrow vein
Summary:
Within the Project area, the main rock types are Archean granites and metasedimentary rocks of the Quetico Subprovince, and Keweenawan Supergroup mafic to ultramafic intrusive rocks and related intermediate to mafic hybrid intrusive rocks of the Mid-continent Rift.
The Current, Escape, and Lone Island Lake North and South intrusions appear to be connected by the diffuse East West Complex which consists of a series of moderately-dipping hybrid sills and dykes that are confined to the Escape Lake Fault Zone which comprises the southernmost part of the Quetico Fault system.
Most of the presently known mineralization is hosted within the Current and Escape intrusions, although disseminated Pt-Pd-Cu-Ni mineralization has also been observed within the Lone Island and 025 intrusions. These intrusions comprise four of the at least five Keweenawan (Mesoproterozoic) age magmatic conduits present along the northwestern edge of the MCR system within the Project boundaries. This group of related intrusions have been collectively termed the Thunder Bay North Intrusive Complex.
The Current deposit has six well defined zones of mineralization that are contiguous along the plunge of the intrusion. Escape deposit has three well defined zones of mineralization that were used within the current Mineral Resource Estimate.
Upper Current/Current Zone
The Current Zone, discovered in late 2006 by Magma Metals, is hosted within a sub-horizontal to gently south-southeast plunging, narrow, oval to bell-shaped magmatic conduit (or chonolith), which is part of the Current Lake Intrusion. The zone ranges from 30 m to 50 m in width and up to 70 m in height, mainly underlying Current Lake.
Bridge Zone
The Bridge Zone comprises the eastern portion of the Current Zone before the tube-like conduit begins to transition into a tabular body within the Beaver West Zone. Mineralization is generally similar to that observed within the Current Zone; however, there are several small, elongated, limited strike-extent net-textured to massive sulphide pools present locally. This zone becomes increasingly bottom-loaded to the east where it joins with the Beaver West Zone.
Cloud Zone
The Cloud Zone was discovered in 2008 and is a distinct low sulphide, high-tenor zone that occurs near the roof of the Beaver Zone of the Current Intrusion and transitions to the west into the upper part of the Beaver West Zone. It comprises a diffuse, irregular cloud of <1% very finely disseminated chalcopyrite and some pyrrhotite that is often very difficult to see visually. This zone is often so subtle that the sulphides comprising it cannot be distinguished in hand specimen until they tarnish after several weeks exposure to the air.
Beaver Zone
The Beaver Zone was also discovered in late 2007 by Magma Metals (Canada) Limited and occurs within the larger, tabular, Beaver portion of the intrusion. It exhibits a shallow east–southeasterly plunge and increases from a width of 100 m and a thickness of 15 m to a width of 550 m and a thickness of 150 m to 175 m in the east. Mineralization is primarily developed in the basal portions of the intrusion (bottom-loaded) within variably feldspathic lherzolite.
Beaver West Zone
This zone has been kept as a separate zone because it contains several different mineralization\trends with directions differing greatly from the mineralized trends observed within other parts of the Current chonolith system. It is characterized by a narrow southeast entrance and an even narrower northwest exit and is located immediately east of where the Bridge Zone tube transitions into a tabular body as it crosses over the Quetico Fault. The thickness of the intrusion hosting the Beaver West Zone is quite variable with an irregular floor hosting several thermally-eroded depressions that sometimes host small, linear massive sulphide pools overlain by variable thicknesses of net-textured sulphides (greater than 25%) grading upward into finely disseminated sulphides.
Beaver East Zone
The Beaver East Zone comprises the southeasterly extension of the Beaver Zone past that portion of the system that was included within the 2010 AMEC historic Mineral Resource Estimate, and it is essentially continuous with the Beaver Zone. The intrusion in this area is up to 200 m thick and about 550 m in width. This zone exhibits the same shallow plunge and extends the Beaver mineralization a further 630 m to the east-southeast. Mineralization is finely disseminated, ranging from a few percent to >25% sulphides, is interstitial to the gangue, and primarily occurs within linear, thermallyeroded depressions within the base of the Beaver portion of the Current Intrusion.
437/SEA Zone
The relatively deep (approximately 650 m below surface), poorly defined 437 Zone was discovered in late 2011 and comprises a separate mineralized zone located approximately 300 m southeast of the Beaver East Zone. It occurs within the eastern part of the Current Intrusion where the intrusion morphology transitions from a steep-sided trough to a more open basal feature merging into the SEA portion of the Current Intrusion.
There are presently three mineralized zones defined within the Escape Intrusion, which are from north to south: Steepledge North; Steepledge South; and the Escape HGZ.
Steepledge North
The Steepledge North was discovered by Magma Metals (Canada) Limited in late 2008 and consists of a poorly defined, approximately 200 m long, weakly to locally moderately mineralized zone located beneath the central and southern portions of Steepledge Lake. In this area the mineralization and the conduit are similar to that observed within the Current Zone 3 km to the east; however, the grades are much lower, and the conduit is wider and thicker (50 m to 75 m wide and up to 100 m in height).
Steepledge South
The Steepledge North was discovered by Magma Metals (Canada) Limited in late 2008 and consists of a poorly defined, approximately 200 m long, weakly to locally moderately mineralized zone located beneath the central and southern portions of Steepledge Lake.
Ribbon Zone
The Ribbon Zone was discovered by RTEC in early 2008 and presently comprises a roughly approximately 350 m long, poorly drill-defined, elongate, relatively narrow, sub-horizontal, band of disseminated mineralization, similar to the more diffuse portions of the Beaver Zone within the Current deposit.
Escape South
The Escape South Zone is a very well-mineralized, relatively flat-lying (sub-horizontal), elongated disk-like zone exhibiting an overlying and connected central sail and an underlying, discontinuous central keel. This mineralization overlies a localized, deep, steep-sided, thermally-eroded depression within the floor of the intrusion.
Escape South HGZ
The Escape South HGZ comprises a 200 m long, 100 m wide, and 10 m to 90 m thick heavily disseminated to net-textured zone that is located within a geologically complex portion of the southern Escape Intrusion. It is a tabular, sub-horizontal, relatively high grade sulphide body with an upper “fin” shape (sail) and a discontinuous lower "keel” shape that is always situated over, but not at the base of, a pronounced, localized, steep-sided, thermally-eroded depression in the floor of the intrusion.
Escape South Perimeter
The Escape South Perimeter Zone consists of finely disseminated, sub-horizontal wings of mineralization that extend outward in all directions from the Escape South HGZ Zone. This zone is thinner (generally between 5 m to 15 m thick) and contains 3% to 15%, finely disseminated sulphides (pyrrhotite and chalcopyrite) when compared to the usually net-textured HGZ that it encloses.
Mining Methods
- Drift & Fill
- Cross-cut drift
- Longhole open stoping
- Cemented backfill
- Backfill
Summary:
The proposed operation involves underground mining at a rate of 3,600 t/d with an accompanying process plant with a matching 3,600 t/d capacity.
The Current deposit is accessed via a portal from surface and has a 12-month pre-production development period, which allows for the Current deposit main decline system to connect to the Current main fresh air raise and provide secondary egress for the mine. Contractor decline development is assumed for the 12-month pre-production period as well as the following 2 years.
The Escape deposit is accessed via a separate portal from surface. The main decline development begins 12 months after the Current deposit decline begins and continues for 3 years, until the decline connects with the Escape main fresh air raise. Contractor decline development is assumed for the Escape deposit.
The Current and Escape deposits will be mined via a combination of conventional underground long hole open stope and drift & fill mining methods, backfilled with a combination of CPB, CRF and URF. Stopes are designed to be accessed and excavated via overcut and undercut development cross-cut drifts, which connect to the main declines. The main declines provide ventilation, haulage to surface, and mine access.
Stopes are accessed via cross cuts from the main ramp systems. In situations where the height of the mineralized material within the conduit is less than 25 m, only undercut access is driven. Stopes are drilled, blasted, mucked and backfilled via the undercut; these stopes are assumed to be mined via upholes. In situations where the mineralized material within of the conduit is 25 m, both overcut and undercut accesses are driven. Stopes are drilled, blasted and backfilled from the overcut and mucked via the undercut; these stopes are assumed to be mined via downholes. In situations where the height of the mineralized material within the conduit is greater than 25 m, the bottom 25 m is assumed to be mined via downhole stoping and the remaining portion above is assumed to be mined via uphole stoping. In situations where the height is above 50 m, the bottom multiples of 25 m are assumed to be mined via downhole stoping and the remaining portion above is assumed to be mined via uphole stoping. . Downhole stopes are designed to be drilled via in-the hole (ITH) production drills and uphole stopes are designed to be drilled via tophammer (TH) production drills.
DAF stoping is utilized in areas where the height of the mineralization is not sufficient for LHOS or the mining area is not well suited for LHOS. DAF begins with a single 5 x 5 m drift. Depending on whether adjacent DAF stopes are above or beside the original drift, the adjacent DAF stope can be breasted or slashed into the original drift.
The declines are designed as 5 x 5 m at an average gradient of 15%. Cross cuts and level accesses are designed at 5 x 4.5 m. The lateral development is sized for the operation of the mining equipment fleet required for stope extraction and includes allowances for ventilation ducting and services. An additional 24% was added to the Current deposit decline metres and 15% to the Escape deposit decline metres to account for remucks, power and primer magazines, electrical substations, sumps and ventilation accesses.
The feed to the mill is primarily sourced from LHOS and DAF stope production; however, 9.5% of mill feed is expected from cross-cut development.
LHOS stopes are drilled via long hole drill and loaded/blasted via hand (downholes) or emulsion loader (upholes). DAF stopes are drilled via jumbo and blasted via ammonium nitrate/fuel oil (ANFO) loader. All stopes are excavated via 10-tonne LHD and loaded into 40-tonne underground haul trucks and hauled to surface. Haul trucks within the Current deposit transport the material to a surface ROM pad located near to the portal. Haul trucks within the Escape deposit transport the material to the portal access and deposit it into a stockpile. The stockpile is loaded into surface haul trucks and hauled to the ROM pad by contactor. Roughly half of mill feed is expected be redeposited underground as CPB, CRF or URF backfill.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Jaw crusher
|
.......................
|
|
225 kW
|
1
|
Cone crusher
|
|
|
|
1
|
SAG mill
|
|
6.7m x 2.8m
|
2.75 MW
|
1
|
Ball mill
|
|
4.6m x 7.0m
|
2.75 MW
|
1
|
Vertical mill / Tower
|
|
|
|
1
|
Summary:
The crushing circuit is designed to reduce ROM ore with a nominal moisture content of 3% w/w and an F80 of 914 mm to feed the mill comminution circuit at a P80 of 200 mm.
ROM ore is transported by LHD loader from the underground mine to a surface ROM stockpile. A front-end wheel loader will feed ROM ore from the stockpile to the crusher. Crusher feed ore will be dumped through a grizzly that will screen the ore to 914 mm minus before feeding the jaw crusher, where it is reduced to a P80 size of 200 mm. A Metso-Outotec C150 Jaw Crusher has been selected for the service. A remote-operated rock breaker will be installed at the dump point to reduce oversize material caught by the grizzly.
The crusher will operate at a nominal rate of 400 mtph which corresponds to a planned utilization of 37.5%. This allows hauling/crushing to occur within a single shift basis.
A product bin is located at the primary crusher outlet, crushed ore drops into the ore bin which is fitted with a discharge apron feeder which feeds a loadout conveyor.
A belt magnet is located on the loadout conveyor to remove tramp ferrous material entrained in the ore before it leaves the crusher building complex. A belt weigh scale on the loadout conveyor tracks the production rate of the crushing plant.
A baghouse collects dust at the ore transfer points within the primary crusher building, which once collected, will report to the tail end of the loadout conveyor. A sump pit is provided to collect washup residue and is designed to be emptied periodically by vacuum truck.
The grinding circuit will consist of a conventional semi autogenous ball mill crusher (SABC) arrangement and has been designed to produce feed slurry fine enough for effective flotation. Design parameters for the circuit include an F80 of 203 mm and a ball mill closed-in with hydrocyclones. A hydrocyclone overflow P80 of 65 µm will report to the roughing circuit for the first stage of flotation.
The grinding circuit is designed to produce feed slurry fine enough for effective flotation. Primary grinding will be achieved with a SAG mill. The SAG mill slurry will discharge through a double deck vibrating screen where the oversize material will be classified and diverted to a pebble crusher.
Product of the pebble crusher will be returned to the SAG mill feed. SAG mill discharge screen undersize will report to the common mill pump box to be pumped to the hydrocyclone. The ball mill will be fed by the cyclone underflow and will recirculate back into the pump box. The recirculating load through the ball mill and cyclone will be 250%. Process water will be added to the grinding circuit to achieve a pulp density of 71% w/w feeding the hydrocyclones, equating to the cyclone overflow discharging a 30% solids w/w slurry to the copper roughers bank.
Processing
- Filter press plant
- Dewatering
- Flotation
Flow Sheet:
Summary:
The conceptual process plant was designed using conventional and proven technology. It is designed for a throughput of 3,600 metric tonnes per day (mtpd) at a planned availability of 92% per annum. The beneficiation plant will operate a planned 360 days per year, equating to an annual feed of 1,296,000 metric tonnes. The plant will produce two separate concentrates from the ore feed. The first process circuit will produce a copper concentrate primarily containing PGEs. The second circuit will produce a bulk concentrate recovered from the tailings of the copper circuit, containing additional PGEs and remaining sulphides. The two concentrates will be sold in the open market.
Copper Concentrate Circuit
The copper concentrate circuit will consist of a roughers bank, hydrocyclone cluster, regrind mill, first cleaners bank, and a secondary cleaner column cell. The copper roughers flotation stage will utilize mechanical tank cells in series, equipped with agitators. Feed slurr ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Platinum
|
Recovery Rate, %
| 82 |
Platinum
|
Head Grade, g/t
| 1.59 |
Palladium
|
Recovery Rate, %
| 86 |
Palladium
|
Head Grade, g/t
| 1.56 |
Copper
|
Recovery Rate, %
| 95 |
Copper
|
Head Grade, %
| 0.41 |
Nickel
|
Recovery Rate, %
| 51 |
Nickel
|
Head Grade, %
| 0.21 |
Gold
|
Recovery Rate, %
| 80 |
Gold
|
Head Grade, g/t
| 0.1 |
Silver
|
Recovery Rate, %
| 68 |
Silver
|
Head Grade, g/t
| 2.15 |
Platinum Equivalent
|
Head Grade, g/t
| 7.31 |
Reserves at November 1, 2021:
Category | Tonnage | Commodity | Grade | Contained Metal |
Indicated
|
14,553,324 t
|
Platinum
|
1.54 g/t
|
719,518 oz
|
Indicated
|
14,553,324 t
|
Palladium
|
1.58 g/t
|
741,426 oz
|
Indicated
|
14,553,324 t
|
Copper
|
0.42 %
|
61,126 t
|
Indicated
|
14,553,324 t
|
Nickel
|
0.23 %
|
33,131 t
|
Indicated
|
14,553,324 t
|
Gold
|
0.1 g/t
|
47,322 oz
|
Indicated
|
14,553,324 t
|
Silver
|
2.3 g/t
|
1,075,381 oz
|
Indicated
|
14,553,324 t
|
Cobalt
|
167 g/t
|
2,435 t
|
Indicated
|
14,553,324 t
|
Rhodium
|
0.05 g/t
|
23,511 oz
|
Indicated
|
14,553,324 t
|
Platinum Equivalent
|
8.12 g/t
|
3,798,581 oz
|
Indicated
|
14,553,324 t
|
Palladium Equivalent
|
3.55 g/t
|
1,662,522 oz
|
Indicated
|
14,553,324 t
|
4E (Pt, Pd, Rh, Au)
|
3.27 g/t
|
1,531,777 oz
|
Inferred
|
8,077,595 t
|
Platinum
|
0.69 g/t
|
179,130 oz
|
Inferred
|
8,077,595 t
|
Palladium
|
0.67 g/t
|
173,829 oz
|
Inferred
|
8,077,595 t
|
Copper
|
0.33 %
|
26,329 t
|
Inferred
|
8,077,595 t
|
Nickel
|
0.15 %
|
12,009 t
|
Inferred
|
8,077,595 t
|
Gold
|
0.07 g/t
|
17,508 oz
|
Inferred
|
8,077,595 t
|
Silver
|
1.07 g/t
|
276,702 oz
|
Inferred
|
8,077,595 t
|
Cobalt
|
138 g/t
|
1,119 t
|
Inferred
|
8,077,595 t
|
Rhodium
|
0.01 g/t
|
1,724 oz
|
Inferred
|
8,077,595 t
|
Platinum Equivalent
|
4.07 g/t
|
1,057,646 oz
|
Inferred
|
8,077,595 t
|
Palladium Equivalent
|
1.78 g/t
|
462,899 oz
|
Inferred
|
8,077,595 t
|
4E (Pt, Pd, Rh, Au)
|
1.43 g/t
|
372,191 oz
|
Corporate Filings & Presentations:
Document | Year |
Corporate Presentation
|
2022
|
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|
2021
|
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|
2021
|
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2021
|
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|
2021
|
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|
2021
|
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|
2021
|
...................................
|
2019
|
Preliminary Economic Assessment
|
2011
|
- Subscription is required.
News:
News | Date |
Clean Air Metals Reports Drill Results from the Escape Deposit including Hole 129 with 90.0m averaging 1.04 g/t Platinum, 1.33 g/t Palladium...
|
April 27, 2022
|
Clean Air Metals Drill Results from the Escape Deposit Steepledge extension includes 15.0m averaging 1.73 g/t Pt, 1.92 g/t Pd, 0.70% Cu, 0.30% Ni
|
March 31, 2022
|
Clean Air Metals Files Preliminary Economic Assessment Technical Report for the Thunder Bay North Property on SEDAR
|
January 13, 2022
|
Clean Air Metals Drill Results from the Thunder Bay North Project includes 31.0m averaging 3.9 g/t Pt, 5.1 g/t Pd, 1.7% Cu, 0.63% Ni. 2022 drilling set to restart
|
January 5, 2022
|
Clean Air Metals Announces a PEA of the Current and Escape PGE-Cu-Ni Deposits of the Thunder Bay North Project, with post-tax NPV5 of C$378m, IRR 29.8%
|
December 1, 2021
|
Benton Receives Extended Terms from Panoramic on the Thunder Bay North Project and Provides Update
|
November 11, 2019
|
Benton and Panoramic to Extend Terms for Agreement on Thunder Bay North Project
|
October 1, 2019
|
- Subscription is required.