Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Sulfuric acid (reagent)
- Acid plant
- Smelting
- Smelting
- Flotation
- ROM/dump leach
- Solvent Extraction & Electrowinning
|
Mine Life | 11 years (as of Jan 1, 2021) |
Source:
p. 24

Southern Copper Corporation (SCC) is an indirect subsidiary of Grupo Mexico S.A.B. de C.V. (Grupo Mexico) which, as of December 31, 2021, owns 88.9% of SCC through its wholly-owned subsidiary Americas Mining Corporation (AMC). SCC’s operations in Mexico are conducted through its subsidiary, Minera Mexico, S.A. SCC owns 99.6% of Minera Mexico.
Minera Mexico operates La Caridad unit through Mexicana de Cobre, S.A de C.V.
Deposit Type
- Porphyry
- Breccia pipe / Stockwork
Summary:
La Caridad is emplaced in a metallogenic province that is notable for Cu, Mo, gold (Au), silver (Ag), and platinum (Pt) Resources (Titley, 1995). It contains more than 50 deposits, some of which are considered giant ore deposits. Porphyries are Upper Paleocene to Lower Eocene in age and often exhibit supergene enrichment, which forms during exhumation of the hydrothermalized rocks towards the surface.
The largest mineralized districts in northwest Mexico occur in two main intervals, one at 59–63 Ma (Cananea), and the other at 53–55 Ma (La Caridad District), where associated magmatism overlaps in space and time. La Caridad porphyry intruded the thick-skinned Laramide orogen and is the southernmost giant porphyry Cu deposit belonging to the cluster of Arizona-Sonora Cu porphyries.
The deposit occurs exclusively in felsic to intermediate intrusive igneous rocks and associated breccias. The host rocks include diorite and granodiorite intruded by a quartz-monzonite porphyry stock and by numerous breccia masses that contain fragments of all the older rock types.
The main mineralization at La Caridad occurs in the Quartz-monzonite porphyry and hydrothermal breccias. The host rocks at La Caridad are andesites, with the oldest rocks corresponding to the Laramide volcanic rocks, which are regionally correlated with the Tarahumara Formation. These consist of lavas and tuffs of intermediate composition with aphanitic to porphyritic texture, including agglomeratic horizons and brecciated pyroclastic flows and fine-grained tuff. Locally, this andesitic volcanic sequence was intruded by a granodiorite which is well exposed to the east southeast of the La Caridad mine, which are in turn intruded by diorite dikes that range from fine to coarse grain. Discordantly overlying this igneous complex is a sequence of rhyolitic flows, dated by K-Ar at 51.3 ± 1.0 Ma.
Intense fracturing, with multiple fracture directions are observed at La Caridad. More than 560 local faults and fractures were measured in the La Caridad open pit at benches 1380 and 1305. This data exhibits two dominant trends to include the northeast (NE) and northwest (NW). Fracture density increases northward from the upper to the lower benches, consistent with the location of the mineralized center at the northern end of the open pit. Fractures appear to have provided important controls to the hypogene mineralization, particularly toward the margins of the deposit. Both pre mineral and post-mineral fractures influenced the supergene mineralization.
Primary mineralization occurs in the deposit in disseminated form, in fractures and in-filling breccia cavities. In the central part of the deposit, the presence of pyrite and chalcopyrite occurs mainly in disseminated form. There is a direct relationship between the amounts of pyrite and chalcopyrite mineralization and the quartz-sericite hydrothermal alteration. The primary disseminated mineralization occupies approximately 70% of abundance in the central part of the deposit, which as it moves away from the center toward the outside, decreases as dissemination and increases in the fractures and cavities of the breccias.
Molybdenite occurs gradually in fine aggregate crystals accompanied by variable amounts of quartz, filling thin fractures in the quartz monzonite porphyry. Generally, pyrite, chalcopyrite and molybdenite occur as a mixture filling fractures.
The Cu has been completely leached from the oxide zone of the deposit, commonly also referred to as leached exhaust. The oxide zone is thickest in the central part of the deposit and gradually decreases in thickness as it approaches the marginal areas of the deposit. The thickness of the leached zone varies from 10 m to 230 m with an overall mean of 50 m. This zone is mainly represented by Cu oxides and carbonates such as cuprite, tenorite, azurite, plus native Cu. The limits are approximately between elevations 1755 and 1665.
Summary:
The ore at La Caridad is recovered using open-pit conventional truck and shovel mining methods due to the proximity of the ore to the surface and the physical characteristics of the deposit. The current operation is expanding into an area called Bella Union which is south of the existing pit. The ore from the main pit and the expansion area is hauled to the primary crusher located near the maintenance facility or to the Guadalupe leach pads. Waste is hauled to valley OSFs located to the west of the pit.
La Caridad is an established operation that currently mines at a rate of about 98 million tonnes per year of total material. The operation currently runs 6 electric shovels, 1 hydraulic shovel, 6 loaders, and 36 trucks of varying size and models.
The mining operation begins with the drilling process; drill samples are sent to an assay laboratory for analysis. The assay results are used to mark out zones of ore, leach, and waste rock, which are mined separately. Currently the site uses 5 electric drills and 1 diesel blasthole drill to meet production requirements.
After the blasting is completed, ore, leach, and waste are mined by excavators loading onto trucks. The fleet consists of 6 electric shovels, 1 hydraulic shovel, 6 front end loaders, and 36 mining trucks. Overburden and waste loads can be used for fixing roads, building ramps, or simply placed on the OSFs.
The mine design criteria are listed below:
1. Surface mining approach.
2. Minimum operating width of 60 m.
3. Haul road design width of 40 m.
4. Bench height of 15 m.
5. Maximum road grade of 10%.
6. Bench face angle and catch berms vary based on geotechnical sector.
7. Typical blasting grid ranging from 7x7 m, 8x8 m, 8x10 m, 9x11 m.
8. Final wall Control Drill Pattern of 5x5m.
9. Blasthole diameter of 12 ¼”.
10. Rock density average of 2.5.
Waste is hauled to one of three OSFs listed below:
- North OSF
- West OSF
- Southwest OSF
The OSFs are design based on a 37° angle of repose and a 1.77 t/m3 loose density. The North OSF has a capacity of 89 Mt, the West OSF has a capacity of 195 Mt, and the Southwest OSF is the largest with a capacity of 1,625 Mt. The total OSFs capacity is 1,909 Mt.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Gyratory crusher
|
|
60" x 89"
|
|
2
|
Cone crusher
|
.......................
|
|
|
6
|
Cone crusher
|
.......................
|
|
|
12
|
Ball mill
|
|
16.5' x 24'
|
|
12
|
Regrind
|
|
10.5' x 23'
|
|
4
|
Summary:
The Crushing and Screening Plant includes the following equipment and processes:
- Primary Crushing (Two 60-inch x 89-inch gyratory crushers);
- Ore conveyor to Coarse ore stockpile (72 inch by 970 m);
- Coarse ore storage yard (240,000 metric tonnes capacity; 165,000 dry tonnes live capacity);
- Secondary Screens (Six double deck 6 ft by 16 ft);
- Secondary Crushing (Six MP-800);
- Tertiary Screens (Twenty double deck 8 ft by 20 ft);
- Tertiary Crushing (Twelve Allis Chalmers 3 inch by 84 inch).
The primary crushing circuit includes two 60-inch by 89-inch gyratory crushers The primary crushers are located near the final pit limit. The run-of mine material is transported to the primary crusher with haul trucks. The haul trucks discharge directly into the crushers. The crushing circuit was designed to process 72,000 dry tpd (75% availability) with 8-inch closed size setting (P80 minus 8 inch) in 18 hours of operation. The ROM oversize material is broken with a hydraulic breaker.
The primary crushed material is conveyed to a coarse ore stockpile area. When full, the coarse ore stockpile provides almost two days of surge capacity to protect the downstream circuits from any eventualities in the primary crushers or the mine.
The primary crushed ore is reclaimed with feeders and transported to two subsequent stages of screening and crushing in closed circuit to further reduce the material to minus ½ inch. Conveyor belts are used to transport the intermediate and fine crushed materials throughout the entire crushing and screening circuit.
The crushing circuit design includes weigh scales, crushed ore sampling system and magnetic separators to protect the cone crushers from iron debris coming from mining operations. The crushed product is transported to a fine ore storage building with 309,000 tonnes live capacity. When full, the fine ore storage provides almost three days of surge capacity to protect the beneficiation circuits from any eventualities in the crushing and screening plant.
Grinding equipment includes:
-Primary grinding mills (Twelve 16.5-ft diameter by 24 ft long);
-Regrind mills (Four 10.5-ft diameter by 23 ft long).
The milling section consists of twelve primary grinding mills. The material is ground to 66% minus 200 mesh (75 microns) in closed circuit with a battery of size classification cyclones. Flotation reagents are added into the grinding mill to allow for conditioning. The mill discharge slurry is pumped to banks of cyclones for size classification. Finely ground slurry (cyclone overflow) at approximately 32% solids is sent to a conditioning tank where flotation reagents are added for conditioning prior to the flotation process. Cyclone underflow is returned to the mills for further grinding.
Processing
- Sulfuric acid (reagent)
- Acid plant
- Smelting
- Smelting
- Flotation
- ROM/dump leach
- Solvent Extraction & Electrowinning
Flow Sheet:
Summary:
The La Caridad complex includes an open-pit mine, concentrator, smelter, copper refinery, precious metals refinery, rod plant,SX-EW plant, lime plant and two sulfuric acid plants.
Copper Concentrator
The current mineral processing facility is comprised of crushing and milling circuits to achieve liberation of copper mineralization. Copper contained in primary and secondary copper minerals is recovered via flotation into a copper concentrate. The concentrate is shipped to their own smelter located approximately 20 km from the beneficiation plant.
The Concentrator includes the following equipment and processes:
- Fine ore storage (309,000 wet tonnes capacity).
- Primary grinding mills (Twelve 16.5-ft diameter by 24 ft long).
- Rougher Flotation (100 cells – 1350 cubic feet [ft3] per cell; 40 cells – 1,000 ft3 per cell).
- Regrind mills (Four 10.5-ft diameter by 23 ft long).
- Scavenger flotation (48 cells – 500 ft3 per cell).
- Fir ........

Recoveries & Grades:
Commodity | Parameter | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Copper
|
Recovery Rate, %
| ......  | ......  | ......  | 87.1 | 85.5 | 38.3 | 38.6 |
Copper
|
Head Grade, %
| ......  | ......  | ......  | 0.35 | 0.36 | 0.36 | 0.24 |
Copper
|
Concentrate Grade, %
| ......  | ......  | ......  | 23.8 | 24 | 23.5 | 22.8 |
Molybdenum
|
Recovery Rate, %
| ......  | ......  | ......  | 83.3 | 82.5 | 81.2 | 81.6 |
Molybdenum
|
Head Grade, %
| ......  | ......  | ......  | 0.034 | 0.035 | 0.035 | 0.036 |
Molybdenum
|
Concentrate Grade, %
| ......  | ......  | ......  | 54.6 | 54.3 | 53 | 53.8 |
Production:
Since 2019 stripping ratio obtained dividing waste by leachable material plus ore mined.
Commodity | Product | Units | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Copper
|
Cathode
|
kt
| ......  | ......  | ......  | 26 | 28 | 28 | 27 |
Copper
|
Metal in concentrate
|
kt
| ......  | ......  | ......  | 106 | 106 | 105 | 104 |
Copper
|
Concentrate
|
kt
| ......  | ......  | ......  | 446 | 443 | 447 | 455 |
Molybdenum
|
Metal in concentrate
|
kt
| ......  | ......  | ......  | ......  | ......  | ......  | ......  |
Molybdenum
|
Concentrate
|
kt
| ......  | ......  | ......  | ......  | ......  | ......  | ......  |
Silver
|
Metal in concentrate
|
koz
| ......  | ......  | ......  | ......  | ......  | ......  | ......  |
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Operational Metrics:
Metrics | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
Total tonnes mined
| ......  | ......  | 94,578 kt | 96,541 kt | 98,534 kt | 98,435 kt |
Ore tonnes mined
| ......  | ......  | 62,858 kt | 65,439 kt | 71,239 kt | 75,990 kt |
Stripping / waste ratio
| ......  | ......  | 0.5 | 1.78 | 1.84 | 1.84 |
Tonnes milled
| ......  | ......  | 34,648 kt | 34,548 kt | 34,548 kt | 34,539 kt |
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Reserves at December 31, 2021:
An economic cut-off was used rather than the current practice site is using of a COG of 0.12% copper for leach and 0.3% copper for mill.
Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
Probable
|
ROM leach
|
43 Mt
|
Copper
|
0.09 %
|
81 M lbs
|
Probable
|
Sulphide
|
372 Mt
|
Copper
|
0.24 %
|
1,955 M lbs
|
Probable
|
Sulphide
|
372 Mt
|
Molybdenum
|
0.02 %
|
185 M lbs
|
Indicated
|
ROM leach
|
817 Mt
|
Copper
|
0.06 %
|
0.5 Mt
|
Indicated
|
Sulphide
|
6,455 Mt
|
Copper
|
0.17 %
|
10.8 Mt
|
Indicated
|
Sulphide
|
6,455 Mt
|
Molybdenum
|
0.026 %
|
|
Inferred
|
ROM leach
|
927 Mt
|
Copper
|
0.06 %
|
0.6 Mt
|
Inferred
|
Sulphide
|
4,039 Mt
|
Copper
|
0.13 %
|
5.1 Mt
|
Inferred
|
Sulphide
|
4,039 Mt
|
Molybdenum
|
0.025 %
|
|
Financials:
| Units | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
Book Value
|
M USD
| ......  | ......  | ......  | 752.2 |
785.1
|
840.2
|
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Corporate Filings & Presentations:
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Aerial view:
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