Overview
| Stage | Production |
| Mine Type | Open Pit |
| Commodities |
|
| Mining Method |
- Truck & Shovel / Loader
- Overhand Cut & Fill
- Sub-level stoping
- Dry waste backfill
- Hydraulic backfill
|
| Production Start | ...  |
| Mine Life | 6 years (as of Jan 1, 2022) |
The Atacocha site includes two mines: the Atacocha underground mine and the San Gerardo open pit mine. The underground mine is suspended, but mining continues in the San Gerardo open pit mine.
In 2022, Nexa Resources has continued to make progress with project to evaluate the optimization of the integration of El Porvenir and Atacocha mines at Cerro Pasco complex. |
Source:
p. 9,31,50,85
| Company | Interest | Ownership |
|
Nexa Resources S.A.
|
75.96 %
|
Indirect
|
|
Nexa Resources Atacocha S.A.A.
(operator)
|
100 %
|
Direct
|
The mine is wholly-owned and operated by Nexa Resources Atacocha S.A.A., which is controlled 91% by Nexa Resources El Pornevir S.A.C., a 99.99% subsidiary of Nexa Resources Peru S.A.A.
Nexa Resources S.A. owns 83.55% interest in Nexa Peru and therefore holds 75.96% of Atacocha mine.
Contractors
- Subscription is required.
Deposit Type
- Breccia pipe / Stockwork
- Vein / narrow vein
- Skarn
- Replacement
Summary:
The Atacocha property is situated in the Pasco region of the Western Cordillera of the Andes mountain range in central Peru, within the Eocene-Miocene Polymetallic, and Miocene Au-Ag Epithermal Belts.
Within the property area the stratigraphic units of primary interest are the Chambara´ Aramachay and Condorsinga formations, as well as other undifferentiated limestone units of the Pucara´ Group, the Goyllarisquizga formation, and stratigraphically overlying basalt layers. Intrusive rocks within the property are variably porphyritic dacite to quartz diorite with hornblende and biotite phenocrysts. Dacitic dikes are sub-divided into 2 units: porphyritic with feldspar phenocrysts and little quartz restricted to the groundmass; and porphyritic with abundant quartz phenocrysts, with minor biotite and hornblende. These dacitic dikes generally trend north-south, and are observed in 3 areas: Santa Ba´rbara/central, south along/parallel to the Atacocha Fault, and south of Section 3. The intrusive suite is part of the Milpo-Atacocha-Vinchos, age dated to 29-26 Ma. The Santa Ba´rbara and San Gerardo stocks are two principal intrusive units within the property.
At Atacocha, mineralization is characterized as either a skarn-, replacement- or hydrothermal vein/brecciastyle mineralization. Skarn-related mineralization generally spatially associated with either the Santa Barbara stock or San Gerardo stock is paragenetically earlier, followed by the hydrothermal minerali ........
Mining Methods
- Truck & Shovel / Loader
- Overhand Cut & Fill
- Sub-level stoping
- Dry waste backfill
- Hydraulic backfill
Summary:
Atacocha operates two mines: the Atacocha underground mine and the San Gerardo open pit mine. The underground mine is currently suspended, but mining continues in the San Gerardo open pit mine.
San Gerardo is an open pit operation located at the top of mineralized zone, and is mined by 6 m high benches. Since the temporally suspension of Atacocha underground mine, the open pit production is responsible by the metallurgical plant feed. Operations are carried out by contractor with a mining fleet that allows selectivity in the loading process.
The Atacocha underground mine is mined by the overhand Cut & Fill (C&F) and sublevel stoping (SLS) mining methods. C&F stopes are 20 m high consisting of 4 m high cuts and a minimum mining width of 4 m. C&F stopes are located 55 m from the main ramps and accessed by stope access ramps with grades varying from -15% to +15%. Production is achieved by horizontal drill and blast, and backfilled using unconsolidated waste fill or hydraulic backfill. The SLS mining method has demonstrated increased productivities and reduced unit costs as compared to the C&F mining method. SLS stopes are located a minimum of 40m from infrastructure, are 20 m high, 30 m long and have a minimum mining width of 4 m. Production is achieved by vertical blastholes, and backfilled using unconsolidated waste fill.
Source:
- subscription is required.
Flow Sheet:
Summary:
- subscription is required.
Reserves at December 31, 2022:
Underground:
Mineral Resources are estimated at a NSR cut-off value of US$ 62.81/t for resources shapes.
The NSR cut-offs are calculated based on the LOM costs using average long-term metal prices of Zn: US$ 3,250.3/t (US$ 1.47/lb), Pb: US$ 2,350.5/t (US$ 1.07/lb), Ag: US$ 22.92/oz.
Open Pit:
Mineral Resources are estimated at a NSR cut-off value of US$23.81/t. Some marginal material with cut-off value of US$21.69t was included.
The NSR cut-offs are calculated based on an average long-term metal price of Zn: US$ 3,250.3/t (US$1.47/lb), Pb US$ 2,350.5/t (US$1.07/lb), Au US$ 1,696.11/oz and Ag US$ 22.92/oz.
| Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
|
Measured & Indicated
|
In-Situ (OP)
|
10.06 Mt
|
Zinc
|
1.07 %
|
108.1 kt
|
|
Measured & Indicated
|
In-Situ (UG)
|
7.07 Mt
|
Zinc
|
4.16 %
|
294.2 kt
|
|
Measured & Indicated
|
In-Situ (OP)
|
10.06 Mt
|
Silver
|
32.2 g/t
|
10,400 koz
|
|
Measured & Indicated
|
In-Situ (UG)
|
7.07 Mt
|
Silver
|
77.2 g/t
|
17,539 koz
|
|
Measured & Indicated
|
In-Situ (OP)
|
10.06 Mt
|
Lead
|
0.97 %
|
97.1 kt
|
|
Measured & Indicated
|
In-Situ (UG)
|
7.07 Mt
|
Lead
|
1.47 %
|
103.6 kt
|
|
Measured & Indicated
|
In-Situ (OP)
|
10.06 Mt
|
Gold
|
0.21 g/t
|
67.6 koz
|
|
Inferred
|
In-Situ (OP)
|
3.84 Mt
|
Zinc
|
1.13 %
|
43.4 kt
|
|
Inferred
|
In-Situ (UG)
|
8.11 Mt
|
Zinc
|
4.45 %
|
360.9 kt
|
|
Inferred
|
In-Situ (OP)
|
3.84 Mt
|
Silver
|
31.7 g/t
|
3,914 koz
|
|
Inferred
|
In-Situ (UG)
|
8.11 Mt
|
Silver
|
82 g/t
|
21,389 koz
|
|
Inferred
|
In-Situ (OP)
|
3.84 Mt
|
Lead
|
1.01 %
|
38.8 kt
|
|
Inferred
|
In-Situ (UG)
|
8.11 Mt
|
Lead
|
1.26 %
|
102.2 kt
|
|
Inferred
|
In-Situ (OP)
|
3.84 Mt
|
Gold
|
0.2 g/t
|
24.7 koz
|
Source:
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Corporate Filings & Presentations:
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