Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Cut & Fill
- Longhole open stoping
- Undefined backfill
|
Production Start | ... |
The Cisneros Operation consists of two underground mines, Guaico and Guayabito, a treatment plant, tailings deposit and a 10 km pipeline.
Antioquia Gold Inc. announces that effective Thursday, July 27 the Company’s Guayabito Mine was ordered to close by the regional environmental agency CORNARE.
The closing order will be extended until the water treatment facility that treats mine discharge water has enough capacity to treat Guayabito Mine effluent.
Antioquia Gold continues to produce from the Guaico Mine and the process plant is working at a normal throughput level. |
Source:
p. 2
The Cisneros operation is 100% held by Antioquia Gold Colombia Limitada., an AGD (Antioquia Gold Inc.) subsidiary.
Contractors
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Deposit Type
- Mesothermal
- Vein / narrow vein
- Intrusion related
Summary:
Mineralization at the Cisneros Project is structurally controlled, and gold is associated with shear zones, breccias and quartz-sulphide veins. The host rocks are mainly granodiorite, quartz-diorite and tonalite.
Hydrothermal alteration of the host rock is narrow around the veins, with carbonates, chlorite, sericite and potassium feldspar being the main alteration minerals. There is a late phase of post-mineral alteration with chalcedony, calcite and zeolite.
The sulphide minerals present are gold, pyrite, chalcopyrite, bismuthinite, galena, sphalerite and molybdenite. However, the order of events (paragenesis) is not yet well-defined.
Native gold and electrum (alloy of gold and silver) show anhedral, subangular to subrounded forms and sizes between 0.001 to 0.082 mm. Gold appears as inclusions in pyrite and chalcopyrite or in veinlets associated with chalcopyrite and bismuthinite.
Based on mineral associations, gold mineralization occurred in two stages. In the first stage, gold is associated with chalcopyrite and in pyrite veinlets, in the second stage, veins of chalcopyrite, bismuthinite and gold cut the pyrite veinlets.
The following deposit descriptions are based in part on an internal report for AGD (Pratt, and Attewell, 2022).
Nus Shear Zone
The Nus shear zone is a composite zone made up of thin ductile shear zones and wider zones of brittle fracturing. The zone varies from approximately 10 m to 45 m in horizontal width and strikes west-southwest with dips ........
Mining Methods
- Cut & Fill
- Longhole open stoping
- Undefined backfill
Summary:
The Cisneros Project consists of two operating, underground mines, Guaico-Nus and Guayabito. The Guaico-Nus Mine is currently accessed by the Guaico portal and decline (4.5 x 4.5 m and 12% gradient) and the Guayabito Mine is also accessed by a portal and decline (4.5 x 4.5 m and 12% gradient).
MINING METHOD
The underground mining methods are cut & fill and Longhole Open Stopping. The selection of the mining methods was determined primarily by deposit geometry and geomechanical features. Cut and fill mining is the preferred mining method for the Guaico and Guayabito veins and longhole mining for the Nus mineralized structure.
The Nus structure is suitable for mining by Long Hole Open Stopping. The 12-metre-long blast holes have been planned by benches from the upper to the lower sublevel. Blast holes will be drilled parallel to the vein’s dip along the entire defined block and following a regular pattern. The aim of the first sequence is to create a free face by blasting and mucking activities.
The preferred mining method for Guaico is a variant of cut and fill, using vertical drillholes for selective mining due mainly to the thickness of veins, rock mass conditions of the hostrock and grade distribution of the Guaico veins.
The main advantage of this method is that it allows selective mining, thereby reducing dilution and increasing mining recovery. Drilling and blasting will be done in two rounds. In the first round only min ........
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Flow Sheet:
Summary:
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Pipelines and Water Supply
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Reserves at October 1, 2022:
Gold cut-off grades of 1.6 g/t (Nus shear), 2.29 g/t (Guaico veins) and 1.82 g/t (Guayabito veins).
Category | Tonnage | Commodity | Grade | Contained Metal |
Measured
|
291 kt
|
Gold
|
4.34 g/t
|
41 koz
|
Indicated
|
457 kt
|
Gold
|
5 g/t
|
73 koz
|
Measured & Indicated
|
748 kt
|
Gold
|
4.74 g/t
|
114 koz
|
Inferred
|
728 kt
|
Gold
|
4.94 g/t
|
116 koz
|
Corporate Filings & Presentations:
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