Joe Mann - Doré Copper Mining Corp

Joe Mann

Location60 km south of Chibougamau, QC
Ownership100% interest
HistoryPast producing underground mine: 1.2 M oz at 8.26 g/t Au 0.25% Cu, from 1956 to 2007
CommoditiesGold and Copper
Current StatusAdvanced exploration
Mineral Resources 2021Inferred: 608,000 tonnes @ 6.78 g/t Au and 0.24% Cu, containing 133,000 contained ounces of gold


Dore Copper has acquired a 100% interest in the Joe Mann gold mine located 60 km by road south from the Company’s Copper Rand mill and 60 km south of Chibougamau, Québec. 

The Joe Mann mine operated in three phases for 27 years, between 1956 and 2007, and produced 1.2 million ounces of gold at a grade of 8.26 g/t Au, 607,000 ounces of silver at a grade of 5 g/t Ag, and 28.7 million pounds of copper at a grade of 0.25% Cu.

In late 2020, Dore Copper completed 8,343 metres of drilling on the Joe Mann property. The results confirmed the high-grade downdip extension of the West Zone and the continuity of the Main Zone below the underground workings of the Joe Mann mine, and highlighted the high-grade potential of the Far West Zone. 

The Corporation reported a NI 43-101 mineral resource estimate (“MRE”) on July 28, 2021 and filed a Technical Report on September 10, 2021. The MRE was unchanged for the preliminary economic assessment (“PEA”).

Dore Copper completed a PEA in May 2022. The PEA contemplates the re-development plan of a hub-and-spoke operation model with Corner Bay as the main feed to the Corporation’s centralized Copper Rand mill, supplemented by the Devlin and Joe Mann deposits. Once the Devlin deposit is mined out (approximately 4 years), production at the Joe Mann mine would start and be funded out of cash flow from operations. Joe Mann benefits from an existing headframe and shaft, including all surface infrastructures.

The Joe Mann mine produced a total of 1,173,238 ounces of gold, 28.7 million pounds of copper, and about 607,000 ounces of silver from 1956 to 2007 (4.75 Mt grading 8.26 g/t Au, plus 0.25% Cu and 5 g/t Ag). The ore was processed at the Copper Rand mill (60 km north) from 2005 until its closure in 2007.

Gold-bearing mineralized showings on the property were discovered in 1950. In 1952, a first 450 feet (137 meters) deep shaft is sunk and further deepened to 1,250 feet (381 meters) in 1954. The Joe Mann mine operated during three different periods.

Period 1: From 1956 to 1960, 135,048 ounces of gold were produced with Shaft #1 deepened to 1,840 feet (561 meters) in 1959. Mining stopped in 1959 due to poor economics. A fire destroyed the mill in 1961 and the plant set up was dismantled afterwards. 

Period 2: In 1973-74, an exploration ramp (Uddlen ramp) is sunk 1.5 km west of the mine to verify the possible western extension of the Main Zone mineralization and the dewatering of the shaft and reconstruction of the mine infrastructures is completed to extract and treat on site at 750 t/day. In 1974-75, 173,143 short tons grading 0.154 oz/t of gold is processed at the mill. The mine closes again due to poor economics. 

Period 3: In 1983, Campbell Resources acquired a minority position in the project and became the sole owner in 1987. The mine was dewatered in early 1985 and underground drilling proved approximately 800,000 tons of ore. Production started in April 1987. During 1989, a new production shaft was sunk to a depth of 2,050 feet (625 meters) and eventually deepened to 3,757 feet (1,145 meters) in 1997-98. In 1999, operations were significantly affected by ground control problems and excessive dilution, which resulted in the temporary suspension of development and mining operations. Mining operations resumed in April 2000 but were again suspended temporarily in November 2000. Mining extraction resumed in April 2002, using mainly long-hole mining method. Extraction was halted in August 2007 due to persistent losses (considering metal prices at that time) and Campbell’s decision to focus on other development projects and not to deepen Joe Mann’s development past the 1,050-meter level. 

In September 2007, Gold Bullion Corp. took an option on the Joe Mann property and completed three diamond drill holes from the 3,100 ft (945 meters) level. The first hole (EE-189B) intercepted the Main Zone at 170 m underneath the lowest level (3,450 ft or 1,052 meters) and retuned 26.66 g/t Au and 0.40% Cu over 1.88 meters and 14.72 g/t Au over 1.2 meters. Hole EE-188 also intersected the Main Zone with 30.3 g/t Au and 1.3% Cu over 3.02 meters, and in the South Zone, 9.23 g/t Au over 0.91 meter. Hole EE-190 did not reach the Main Zone. Lacking the financial resources to further continue this exploration program, Gold Bullion dropped the option and the mine was allowed to flood during the spring of 2008.

In late 2020, Dore Copper completed 8,343 meters of drilling at the Joe Mann property testing the depth extension of the Main and West Zones, and other structures on the property. Highlights of the drilling program included:

Main Zone – Two holes tested the Main Zone below the underground workings to test the continuity of the high-grade gold mineralization identified by two prior holes drilled in 2008 after the mine had ceased operations (refer to above – History). Hole JM-20-02A intersected the Main Zone shear zone approximately 120 meters up-dip from these two historical intercepts and returned two intercepts of 1.3 meters of 6.32 g/t Au and 0.52% Cu, including 0.45 meter of 17.7 g/t Au and 1.23% Cu; and 5.95 meters of 2.29 g/t Au, including 1.7 meters of 5.64 g/t Au.

West Zone – Four holes tested the downdip extension of the West Zone, which was mined from 2004 to 2007 up to a depth of 890 meters. All four holes intersected the West Zone at depths of 270 to 400 meters below the mined area. The best hole (JM-20-06W3) intersected 4.0 meters of 10.34 g/t Au and 0.27% Cu and at a further 11 meters downhole intersected 0.5 meter of 13.70 g/t Au and 0.42% Cu. These two intercepts are located 100 meters down plunge from historical high-grade intercepts of 5.0 meters of 10.3 g/t Au (hole EW78_D), 3.2 meters of 16.1 g/t Au (hole EW79_D), and 3.3 meters of 10.4 g/t Au (hole EW57_D). 

Far West Zone – Four holes totaling 1,230 meters tested the Far West Zone. Three holes intersected gold mineralization confirming the nuggety nature of this zone. The best intercept returned 8.5 meters of 3.92 g/t Au (including 3.0 meters of 10.0 g/t Au, which included 0.7 meter of 35.2 g/t Au), and 0.5 meter of 9.2 g/t Au in hole JM-20-10. The Far West Zone is located approximately 900 meters west along strike from the westernmost part of the Main Zone of the Joe Mann mine. Historically, the Far West zone was accessed by the Uddlen ramp to the west and an exploration drift at a depth of 137 meters. The Far West Zone is characterized by very heterogeneous gold distribution, nuggety in nature, and historically has returned some shallow, very high-grade gold intercepts including: 3.81 meters of 20.8 g/t Au (hole H214), 3.26 meters of 107.0 g/t Au (hole H118), and 3.53 meters of 39.2 g/t Au (hole H258).  

South South Zone – Three holes totaling 402 meters indicated weak gold mineralization and did not replicate a shallow, high-grade gold intercept of 0.8 meter at 32.0 g/t Au. The South South zone is approximately 300 meters south of the Main Zone. The structure is exposed at surface and historically 14 holes were drilled over a strike length of approximately 1 kilometer. 

Following this drilling program, in July 2021, the Corporation reported a mineral resource estimate of  608,000 tonnes at an average grade of 6.78 g/t Au for 133,000 contained ounces of gold in the Inferred category.

The Joe Mann mine is hosted in the upper part of the Obatogamau Formation. From north to south and base to top, the stratigraphy consists of: (1) a gabbro sill; (2) deformed and altered basalt; (3) a thin horizon of rhyolite or felsic tuff; and (4) basalt. The stratigraphy is east-west and dips sub-vertically, and is metamorphosed to the upper greenschist facies (epidote amphibolite facies).

Joe Mann is characterized by east-west striking shear hosted veins that extend beyond 1,000 meters vertically with mineralization identified over a 3 km strike length. These shear zones form part of the Opawica-Guercheville deformation zone, a major deformation corridor cutting the mafic volcanic rocks of the Obatogamau Formation in the north part of the Caopatina Segment. The gabbro sill hosts the Main Zone and the West Zone at the mine, while the South Zone is found in the rhyolite. 

In the mine area, gold mineralization is hosted in quartz-carbonate veins that vary in thickness from five centimeters to 1.5 meters, averaging 0.75 meters. The veins are intensely brecciated and often boudinaged and folded. Gold is closely linked pyrite, pyrrhotite, and chalcopyrite.


Long section
Surface map

Land tenure