What Southern Copper Corporation reports owning in its annual reports to the SEC: buildings, land and equipment, real estate and locations, investments, intangible assets and inventory, at the end of its latest fiscal year and a year before.
The following maps show the locations of our principal mines, smelting facilities, refineries and projects. We operate open-pit copper mines in the southern part of Peru—at Toquepala and Cuajone—and in Mexico, at La Caridad and Buenavista. We also own five underground mines, three out of which currently produce zinc, copper, silver and gold.
The rest of Item 2
The below description of the Company’s mining operations is qualified in its entirety by reference to the Technical Report Summaries included as exhibits to this report and incorporated by reference into this Item 2.
EXTRACTION, SMELTING AND REFINING PROCESSES
Our operations include open-pit and underground mining, concentrating, copper smelting, copper refining, copper rod production, solvent extraction/electrowinning (“SX-EW”), zinc refining, sulfuric acid production, molybdenum concentrate production and silver and gold refining. The extraction and production process are summarized below.
OPEN-PIT MINING
In an open-pit mine, the production process begins at the mine pit, where waste rock, leaching ore and copper ore are drilled and blasted and then loaded onto diesel-electric trucks by electric shovels. Waste is hauled to dump areas and leaching ore is hauled to leaching dumps. The ore to be milled is transported to the primary crushers.
UNDERGROUND MINING
In an underground mine, the production process begins at the stopes, where copper, zinc and lead veins are drilled and blasted and the ore is hauled to the underground crusher station. The crushed ore is then hoisted to the surface for processing.
CONCENTRATING
The copper ore above an established cut-off from the primary crusher or the copper, zinc and lead-bearing ore from the underground mines is transported to a concentrator plant where gyratory crushers break the ore into sizes no larger than three-quarters of an inch. The ore is then sent to a mill section where it is ground to the consistency of fine powder. The finely ground ore is mixed with water and chemical reagents and pumped as a slurry to the flotation separator, where it is mixed with certain chemicals. In the flotation separator, reagent solutions and air pumped into the flotation cells cause the minerals to separate from the waste rock and bubble to the surface where they are collected and dried.
If the bulk concentrated copper contains molybdenum, it is first processed in a molybdenum plant as described below under “Molybdenum Production.” In addition, some of the concentrates contain economic amounts of gold and silver that are recovered in the smelters and refineries.
COPPER SMELTING
Copper concentrates are transported to a smelter, where they are smelted using a furnace, converter and anode furnace to produce either blister copper (which is in the form of cakes with air pockets) or copper anodes (which are cleaned of air pockets). At the smelter, the concentrates are mixed with flux (a chemical substance intentionally included for high temperature processing) and then sent to reverberatory furnaces producing copper matte and slag (a mixture of iron and other impurities). Copper matte contains approximately 65% copper. Copper matte is then sent to the converters, where the material is oxidized in two steps: (i) the iron sulfides in the matte are oxidized with silica, producing slag that is returned to the reverberatory furnaces, and (ii) the copper contained in the matte sulfides is then oxidized to produce copper that, after casting, is called blister copper, containing approximately 98% to 99% copper, or anodes, containing approximately 99.7% copper. Most of the blister and anode production is sent to the refinery and the remainder is sold to customers.
COPPER REFINING
Anodes are suspended in tanks with a solution containing water, sulfuric acid and copper sulfate. A weak electrical current is passed through the anodes and chemical solution and the dissolved copper is deposited on very thin starting sheets to produce copper cathodes containing approximately 99.99% copper. During this process, silver, gold and other metals (for example, palladium, platinum and selenium), along with other impurities, settle on the bottom of the tank (anodic muds). This anodic mud is processed at a precious metal plant where selenium, silver and gold are recovered.
COPPER ROD PLANT
To produce copper rod, copper cathodes are first smelted in a furnace and then dosed in a casting machine. The dosed copper is then extruded and passed through a cooling system that begins solidification of copper into a 60×50 millimeter copper bar. The resulting copper bar is gradually stretched in a rolling mill to achieve the desired diameter. The rolled bar is then cooled and sprayed with wax as a preservation agent and collected into a rod coil that is compacted and sent to market.
SOLVENT EXTRACTION/ELECTROWINNING (“SX-EW”)
A complementary processing method is the leaching and SX-EW process. During the SX-EW process, low-grade sulfides ore and copper oxides are leached with sulfuric acid to allow copper content recovery. The acid and copper solution is then agitated with a solvent that contains chemical additives that attract copper ions. As the solvent is lighter than water, it floats to the surface carrying with it the copper content. The solvent is then separated using an acid solution, freeing the copper. The acid solution containing the copper is then moved to electrolytic extraction tanks to produce copper cathodes.
MOLYBDENUM PRODUCTION
