The Carmacks copper-gold-silver deposit is enclosed within the Early Jurassic Granite Mountain Batholith. The copper mineralization is hosted by amphibolites, gneisses, and intrusive rocks that range from granodiorite to diorite. Copper mineralization occurs along a linear trend, following a brittle-ductile deformation zone. The deposit is sub-divided into several zones, each comprising a tabular raft of amphibolites-gneisses that dip steeply to the east and are up to 100 metres wide, strike up to 700 metres and persist down-dip to at least 450 metres, being open at depth. Previous exploration has identified at least 14 mineralized zones comprising steep easterly dipping zones that occur along a strike length of at least 5 kilometres. The discoveries also include local zones of mineralization that appear sub-parallel to the main mineralized structure. The rafts of copper bearing amphibolites-gneisses are enclosed within a younger granodiorite batholith as roof pendants or partially digested rafts. The copper mineralization at depth comprises copper sulphides bornite and chalcopyrite. However, deep oxidation of the deposit has led to the formation of an oxide cap that can be over 200 metres thick. The oxide mineralization primarly consists of the copper minerals malachite-azurite-tenorite-chrysocolla with minor native copper-cuprite-chalcocite. Gold and silver accompany the copper mineralization; higher gold grades are associated with the more bornite-rich areas.
Mineral Resource and Exploration
Exploration resumed in summer 2014, following a six year hiatus due to a prior focus on feasibility and environmental permitting activities. Copper North engaged in highly focussed exploration programs in 2014 and 2015, spending a total of approximately $1.4M over two years. The programs provided a good return on the value of the dollars spent on exploration by maximizing the use of historical drilling and low-cost exploration methods including ground-magnetics and extensive trenching. The expansion of oxide resources was a priority and the near-surface mineralization was drilled at low-cost as most of the drill holes were less than 150 metres deep and many were less than 75 metres. The result was a significant expansion of oxide and sulphide mineral resources by the announcement of a maiden mineral resource for zones 2000S, 12 and 13 (see News Release dated January 25th 2016; Technical Report on www.sedar.com March 10, 2016). The following table shows the updated total mineral resources for the Carmacks Cu-Au-Ag project.
Zones 1, 4, 7, and 7a Exploration
The focus of drilling and resource definition on the property in 2006-2007 was at zones 1, 4, 7 and 7a. Zone 1 consists of a sub-vertically oriented amphibolite-gneiss structure, striking NNW and dipping at between 65 and 80 degrees to the east. It is up to 50 m wide and extends over a 700 m strike length. The structure is oriented in a NNW-SSE direction and is recognized to at least 450 m down dip. Zone 1 remains open at depth and is oxidized to approximately 230 m in depth. Zones 7 and 7a are shorter narrower mineralized zones, offset from and parallel to the south-western portion of Zone 1, and Zone 4 is an irregular and fault bounded mineralized structure to the southeast of Zone 1. The following table illustrates Measured and Indicated mineral resources of 11,989,000 tonnes grading 1.07% Cu, 0.456 g/t gold and 4.578 g/t silver. These mineral resources are the basis of previous project economics and provide for the first 7 years of mining and leaching of oxide copper, gold, and silver mineralization. The small Inferred resource is within the pit shell for Zones 1, 4, 7 and 7a. With a few more drill holes the Inferred resources could be added to Measured and Indicated categories.
2015 South Expansion Mineral Resource
Zone 2000S Exploration
2000S Zone is located immediately south of the proposed open pit area for zones 1, 4, 7 and 7a. Zone 2000S is defined by a wedge shaped zone having a strike length of approximately 300 metres and a vertical extent of up to 200 metres (see Zone 2000S longtitudinal section). The oxide mineralization extends from surface to depths of up to 120 metres. Sulphide mineralization is found below the oxide zone and is open at depth. Zone 2000S is open to the south and the potential extension warrants future drilling.
The following table shows the mineral resource for zone 2000S.
Zone 13 Exploration (2015)
Zone 13 is up to 100 m wide, strikes for at least 525 m and extends at least 350 m down-dip. The oxides in Zone 13 are near surface and continue to approximately 70 metres depth where they transition to sulphide mineralization. At the transition is a zone of native copper-chalcocite mineralization, for which a separate resource has been estimated. Drill results in the initial fill-in drilling area in Zone 13 are illustrated in the following cross-sections 4400S. A small area of Zone 13 mineralization is covered by a thin (~100 metre), fault-bounded block of late Cretaceous Carmacks Group volcanic rocks and conglomerates. The mineral resource for oxide, transition and sulphide classifications are in the following table.
Zone 13 remains open to the north, south and at depth. The 2015 trenching program in Zone 13 provided more detailed location of oxide copper mineralization and defined new oxide zones. Of particular interest is trenching extending to the north end of Zone 13, where trenching is closing the gap with 2000S Zone, and a hook-shaped magnetic anomaly (section 3500S). The hook-zone magnetics may define a large near surface oxide zone. To the south-west of Zone 13, trenching has exposed a new parallel zone of oxide mineralization in the area of lines 4800S to 5200S. Future drilling programs will target the expansion of Zone 13 to the north, to the south and down-dip. It is unclear whether the northern end of Zone 13 will connect with the southern end of Zone 2000S.
Zone 12 Exploration (2015)
Further to the south in Zone 12, the oxide zone thins and transitions to mixed sulphide and oxide mineralization. Zone 12 comprises three distinct mineralized bodies, possibly representing bifurcations of the zone. Zone 12 is up to approximately 35 m thick, 400 m along strike and has been traced at least 120 metres down-dip. In-fill drilling has focused on only a ~150 m strike length of the 400 m long zone. Zone 12 remains open to the north and it is not clear if it connects with Zone 13. Mineral resources for Zone 12 are given in the following table.
North Zone Exploration (Zone2)
Zone 2 was the focus of the 2014 exploration program. Zone 2 is located approximately 3 km north of Zone 1. Trenching of the north extension of Zone 2 indicates that the zone is cutoff by a cross fault, approximately 20 metres to the northwest of the discovery outcrop and trench. Additional trenching failed to find an extension on the north side of the cross fault. Trenching to the southeast was met with success. The historic Zone 2 trench was refreshed with the excavator and the oxide copper zone was resampled. The shear fabric and distribution of oxide copper minerals indicates a steep dipping mineralized zone, trending east-southeast; sampling yielded 15 metres grading 0.9% copper oxide mineralization. Trenching to the southeast of the discovery trench was successful in tracking the mineralized zone for approximately 500 metres to southeast. Sampling of mineralization was hampered by permafrost capping that limited the downstrike extent. Sampling of the oxide copper mineralization in the new trenches varied from a width of 3 metres grading 0.43% copper to 12 metres grading 1.05% copper. To test the mineralization at depth, ten short drill holes were undertaken. The drill holes intersected the mineral zone at depths between 9.6 metres and 81.0 metres and defined the mineralized structure over a distance of 450 metres. All holes intercepted the mineral zone and yielded an average thickness of 10.5 metres weighted average grade of 0.36% copper, 0.069 g/t gold and 4.37 g/t silver.
Carmack 2014 drill holes:
Sulphide Mineral Resurces
Sulphide mineralization occurs below the oxide mineralization in zones 1, 4, 7 and 7a includes Measured and Indicated resources of 4.340 million tonnes grading 0.75% copper, 0.221 g/t gold and 2.369 g/t silver and an Inferred sulphide mineral resource of 4.031 million tonnes grading 0.71% copper, 0.179 g/t gold and 1.90 g/t silver. These sulphide resources are below the oxide zone of zones 1, 4, 7 and 7a and therefore would not be available for processing until completion of the mining of oxide resource in the proposed open pit. The sulphide mineral resources have not been included in the 2017 Preliminary Economic Assessment due to the fact that there is insufficient information on leach dynamics for the sulphide ores.
The 2015 drilling south of Zones 1, 4, 7 and 7a discovered sulphides to a depth of 100 metres below the oxide transition zone. Sulphide mineralization occurs at a very shallow depth at the south end of Zone 12 and could provide bulk sample for metallurgical test work of sulphide mineralization to determine the economics of leaching sulphide mineralization, and potentially extend the mine life. The prime target for sulphide ores is zones 12 and 13 that have intercepts of up to 99.3 metres grading 0.67% Cu, 0.15 g/t Au. Drilling has intercepted sulphide mineralization to a depth of 200 metres, and the sulphide mineralization remains open to depth .
Mineral Resources and Expansion Opportunity
There are many areas on the property with high potential to expand known mineral resources. The area north of Zone 1 has the greatest potential for increasing oxide resources due to preservation of substantial depth of oxide mineralization.
North Gap Target
The North Gap represents the area between the boundary fault that truncates the north end of Zone 1 and Zone 2, a distance of approximately 2,500 metres. Of interest, part of the target area is covered by near flat lying Cretaceous volcanic rocks, which may well provide an erosional cover that could have preserved the full-depth of oxidized mineralization. The preservation of oxide mineralization to depth, is key to developing additional substantial oxide copper resources. Trenching in 2015 along the margin of the volcanic rocks discovered a zone of limonite-stained amphibolite that may represent the leached cap above a supergene copper zone. This represents a drill-target that has good potential for the discovery of thick zones of oxide copper mineralization.
Weak linear magnetic anomalies extend parallel to strike, to the north of Zone 1, perhaps representing a northwards continuation of the mineral zone. The valley in the North Gap is covered by glacial tills and sands, obscuring the underlying bedrock. Many clasts of copper oxide mineralization have been discovered within the tills, however a bedrock source for these has not been confirmed.
Trenching and drill hole intercepts in Zone 2, have confirmed the continuity of the mineralization to the south of the discovery area. Ground magnetic surveys have indicated a linear anomaly, on trend with the strike of zone 2 that extends for 2,500 metres beyond the known southeastern extent of Zone 2, perhaps representing a continuation of the mineral zone for a total length of 3,000 metres.
Most of the work on the property to date has focused along a single ~3,000 metre north-northeast trend that contains Zones 1, 4, 7, 7a, 12, 13, and 2000S. There are multiple geophysical anomalies that run sub-parallel to this main trend, and may represent almost completely untested mineral zones. A fence of five drillholes tested one of these zones in 2007 and returned intersections of copper sulphide mineralization in three separate holes including 16.37 m of 1.04% Cu, 79.70 m of 0.23% Cu and 41.39 m of 0.18% Cu.
2017 Mineral Resource Expansion
Carmacks Mineral Resource South ExpansionThe mineral resource expansion is in the southern extension of the Carmacks mineral deposit, in Zones 2000S, 13, and 12, on the basis of the step-out and infill drilling program conducted in September and October 2017 and the recently completed updated mineral resource estimate ("Updated Mineral Resource"). The Updated Mineral Resource has been prepared in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") by Independent Qualified Person, Dr. Gilles Arseneau, P.Geo. (See NR April 9, 2018)
Highlights of the Updated Mineral Resource in Zones 2000S, 13, and 12:
Step-out and infill drilling in fall 2017 was successful in confirming continuity of the mineral zones and grades of the oxide and sulphide mineralization in the southern extension of the Carmacks mineral deposit.
Updated Oxide Measured and Indicated Mineral Resource increased to approximately 4,300,000 tonnes - grading 0.47% copper, 0.13 g/t gold and 1.92 g/t silver:
The new Oxide Measured and Indicated Mineral Resource increased 40% over the 2017 Mineral Resource, primarily from lateral expansion of the oxide mineralized zone -- upgrading of the already minor inferred resource category was a small contributor;
The new Oxide Measured and Indicated Mineral Resource in Zones 2000S, 13, and 12 has the potential to provide an additional 2.4 years of mill feed at the planned processing rate of 1.775 million tonnes per year, subject to economic confirmation by future mine development planning; and,
The Updated Sulphide Measured and Indicated Mineral Resource totaled 4,416,000 tonnes grading 0.62% copper, 0.13 g/t gold and 2.3 g/t silver, and an equal tonnage of mineral resource in Inferred category.
Dr. Harlan Meade, President and CEO, commented that "the increase of Measured and Indicated Oxide mineralization in the Updated Mineral Resource for the Carmacks Project confirms there is an opportunity to undertake mine development engineering work on the southern extension to evaluate the potential for extending oxide mineralization mine life and for a potential future shift to mining the sulphide mineralization".Updated Oxide Mineral Resource Zones 2000S, 13, and 12 are located 400 to 2,000 m to the south of the proposed open-pit, defined in the 2017 PEA based on the mineral resources in Zones 1, 4 and 7. The oxide mineral resources occur from surface and extend to depths of 80 to 100 m that may be amenable to open pit mining with a modest strip ratio. The Measured category represents 79% of the total Measured and Indicated resource. The 2017 drill results, including location maps, are available in news releases dated January 8 and January 18, 2018, or at www.coppernorthmining.com.
Table 1. Carmacks Project Updated Oxide Mineral Resource in the Southern Extension Zones - 3 April 2018. Based on a 0.15% acid soluble Cu cut-off grade.
|Oxide - Measured|
|Oxide - Indicated|
|Oxide - Measured+Indicated|
|Oxide - Inferred|
Updated Sulphide Mineral Resource
The Updated Sulphide Measured and Indicated Mineral Resource in Zones, 2000S, 13, and 12 is 4,416,000 tonnes, of which 26% is Measured Resource and 74% is Indicated Resource. The Measured Resource is 1,136,000 tonnes, grading 0.59% copper, 0.13 g/t gold and 2.3 g/t silver. The Indicated Resource is 3,280 tonnes, grading 0.63% copper, 0.13 g/t gold and 2.3 g/t silver. The Inferred Mineral Resource is 4,281,000 tonnes, grading 0.54% copper, 0.12 g/t gold and 1.9 g/t silver. Additional drilling is warranted to confirm the grade, extent, and continuity of the sulphide mineralization, and explore the potential for sulphide resource expansion.
Table 2. Updated Carmacks Project Sulphide Mineral Resource in the Southern Extension Zones -- 3 April 2018. Based on a 0.25% total Cu cut-off grade in Zones 2000S, 13, and 12, and on a 0.15% acid soluble Cu cut-off grade in the Zone 13 Transition.
|Sulphide - Measured|
|Sulphide - Indicated|
|Sulphide - Measured+Indicated|
|Sulphide - Inferred|
The success of exploration in the southern extension of the Carmacks deposit confirms that further exploration of both oxide and sulphide mineralization is warranted. Of particular interest is exploration of sulphide mineralization, both in the southern extension and in Zones 1, 4 and 7.
9 February 2017 PEA Mineral Resource
The Updated Mineral Resources are not included in the 7 year mine life estimated within the current Preliminary Economic Assessment that considers open pit mining 11,550,000 tonnes of the oxide resources of Zones 1, 4, and 7, grading 0.98% Cu, 0.44 g/t Au, 4.34 g/t Ag (see NI 43-101 Preliminary Economic Assessment Technical Report on the Carmacks Project, Yukon, Canada", filed on www.sedar.com on 9 February 2017).