Silver as a Byproduct of Copper Mining: Top Producers

Yes: silver is a byproduct of copper mining at many large mines, and most of the silver mined worldwide comes out of mines built for another metal. The US Geological Survey says silver is mostly a by-product of lead-zinc, copper and gold mines, listed in that order of silver output (USGS Mineral Commodity Summaries, 2026). In 2025, silver from copper operations rose 6 percent and helped lift world mine output by 3 percent to 846.6 million troy ounces, written Moz below (Silver Institute, World Silver Survey 2026, 15 April 2026).

This page follows that silver from the ore body to the refinery. It gives company-reported ounces for 2025, country totals from the USGS, the grade and recovery numbers in one real reserve estimate, and a calculator that shows how small the silver credit is next to the copper. It covers silver recovered from copper ore. It does not cover silver plating on copper wire or silver-copper alloys, which are manufacturing topics.

Is silver a by-product of copper mining?

At many copper mines, yes. A by-product is a metal that is sold alongside the main product but is not the reason the mine was built. A co-product is a metal that earns a large enough share of revenue to count as a second main product. A primary silver mine is one where silver is the main metal. The Silver Institute and its data partner Metals Focus report that primary silver supply fell for the third year in a row, while silver from other metals rose, particularly from copper and gold operations. By-product silver from copper operations grew 6 percent to 237.3 Moz in 2025, which is 28.0 percent of the 846.6 Moz total (Silver Institute and Metals Focus, World Silver Survey 2026). The Silver Institute’s February outlook expects primary silver mines to supply 28 percent of 2026 mine production, which leaves the rest to lead-zinc, copper and gold mines (Silver Institute, February 2026 outlook).

The reason is geology. Porphyry copper deposits, large low-grade bodies formed around cooled magma chambers, supply about 60 percent of the world’s copper and hold about 65 percent of its resources. The USGS model for these deposits gives an average grade of 0.44 percent copper in 2008 and lists silver as a by-product in many of them. It adds that gold and silver are co-products or by-products in about 30 percent of porphyry deposits, and are thought to sit in the copper minerals bornite and chalcopyrite (USGS Scientific Investigations Report 2010-5070-B). Our guide to porphyry copper alteration, grades and discovery covers how these systems are found, and the page on copper deposit types and top countries places them among the other styles.

Copper is not the only route. Silver also comes from lead-zinc ore, from gold mines and from dedicated silver mines. Our overview of silver minerals and silver mining trends covers the silver-bearing minerals themselves.

How silver is recovered from copper ore

Silver in copper ore is not mined as a separate product. It follows the copper through the plant and is pulled out at the refinery. The route for sulfide ore, the type that makes up most of the large porphyry mines, has five steps. The leach-and-cathode route used on oxide copper ore has a different flow sheet and is not covered here.

Infographic

From copper ore to refined silver in 5 steps

1. 1Crush and grindOre is ground fine so metal grains are freed.
2. 2FloatFroth flotation makes a copper concentrate that carries the silver.
3. 3SmeltThe concentrate is melted and made into copper anodes.
4. 4ElectrorefineCopper plates out; precious metals settle as anode slimes.
5. 5Refine slimesThe slimes are refined into silver and gold.

1. Crush and grind. Ore is broken to a fine powder so that the metal-bearing grains are freed.
2. Froth flotation. Reagents make the metal-bearing grains stick to air bubbles. The froth is skimmed off as a concentrate. Molybdenum can be floated out separately, and the US EPA notes that molybdenum can supply a significant share of a mine’s revenue when its price is adequate (US EPA, copper mining and beneficiation profile).
3. Smelting. The concentrate is melted and converted into copper anodes, the slabs that are refined next.
4. Electrorefining. Anodes are dissolved in a bath and pure copper plates onto cathodes. Most of the precious metals in the concentrate end up in anode slimes, the sludge that settles at the bottom of the tank (US EPA, same profile). Codelco reports the gold and silver contained in its anode slimes as a separate line in its annual summary (Codelco, At a Glance, 31 December 2025).
5. Slimes treatment. The slimes are refined further into silver and gold.

A mine that sells concentrate to an outside smelter is paid for its silver under the sales contract. A company with its own smelting and refining facilities, as Southern Copper has in Peru and Mexico, keeps the whole chain in house (Southern Copper, Form 10-K for 2025).

▶ A clay-animation walk through how gold is mined and refined, as a plain-language look at crushing, concentrating and refining; copper ore follows the flotation and smelting route above. · 5:27

Which copper producers report the most silver?

How we chose. The table lists copper-led producers whose own 2025 reports give a silver figure. It is a selection, not a league table, because definitions differ: some figures are silver in concentrate, some are silver produced by all operations of a group, and Glencore’s Antamina and Collahuasi figures are its ownership share. Freeport-McMoRan also lists silver among the products of its Grasberg district in Indonesia and its Cerro Verde mine in Peru (Freeport-McMoRan, second-quarter 2026 release), but its quarterly release gives silver only as quarterly sales, so it is not in the table.

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Southern Copper silver mine production

Million troy ounces per year, all Southern Copper mines

Sources: KGHM, Q4 2025 presentation; Southern Copper 10-K for 2025; Glencore, full-year 2025 production report; Hudbay Minerals, fourth-quarter 2025 results release. KGHM’s tonnes are converted at 32,150.7 troy ounces per tonne.

Inside Glencore’s figure, Antamina in Peru is the largest silver source at 5.97 Moz (Glencore’s 33.75 percent share, up 56 percent from 2024), followed by Collahuasi in Chile at 2.28 Moz (Glencore’s 44 percent share, down 38 percent). The two sit in the same copper department but moved in opposite directions in 2025. Southern Copper explains its 15.3 percent rise in silver output as higher production at Buenavista (up 30.7 percent), La Caridad (up 21.9 percent), IMMSA (up 11.4 percent) and Cuajone (up 4.2 percent), partly offset by Toquepala (down 3.1 percent).

Silver output by country

The USGS estimates world silver mine production at 26,000 tonnes in 2025, up from 25,300 tonnes in 2024. The chart shows the largest producers. These totals count silver from every kind of mine, so they show where silver comes from, not which metal it came with.

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World silver mine production by country, 2025 estimate

Tonnes of silver, largest producers shown, all source metals

Mexico leads at 6,300 tonnes, ahead of Peru at 3,600 and China at 3,400. Chile (1,400 tonnes) and Poland (1,300 tonnes) follow. In Poland, KGHM Polska Miedź reports 1,321 tonnes of silver in concentrate for 2025, about the same size as the USGS national figure. The USGS also puts world silver reserves at 610,000 tonnes, with the largest reserves in Peru (110,000 tonnes), Russia (92,000), Australia (91,000) and China (67,000).

How much silver is in copper ore? A real reserve estimate

Silver grades in copper ore are small. The clearest published example is the El Arco project in Baja California, Mexico, which Southern Copper reports as probable reserves as of 31 December 2025. The sulfide ore is 1,229.5 million tonnes at 0.40 percent copper, 0.14 grams per tonne (g/t) of gold and 1.8 g/t of silver, which the company calculates as 70.5 Moz of contained silver. The reserve estimate assumes the mill recovers 86 percent of the copper but only 50.2 percent of the silver, and the company states that gold and silver were not used when it optimised the pit shell (Southern Copper, 10-K for 2025).

Put in per-tonne terms, a tonne of that ore holds 4 kilograms of copper and 1.8 grams of silver. After recovery, that is 3.44 kg of copper and about 0.9 g of silver. At round example prices of US$10,000 per tonne of copper and US$50 per ounce of silver, the copper is worth about US$34.40 and the silver about US$1.45, so silver is roughly 4 percent of the metal value in this case. The calculator below lets you change every input. Grade is not the same as value: a g/t is one gram in a million grams, while 1 percent copper is 10,000 grams per tonne.

What silver adds to a copper mine’s revenue

At prices near today’s, silver is a useful extra rather than the main income of a copper mine. It matters more in two situations: when the silver grade is high compared with copper, as in some polymetallic ores, and when the silver price jumps. Hudbay reported that its Peru operations beat their cash-cost guidance in 2025 partly because of higher by-product credits, which are the revenue from secondary metals netted off the cost of making copper (Hudbay, fourth-quarter 2025 release). Reported cost per pound of copper therefore falls when the prices of by-products rise.

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Average silver price, 2021 to 2025

US$ per troy ounce, bullion, annual average (2025 is an estimate)

The USGS reports an average bullion price of US$25.23 per troy ounce in 2021, US$28.37 in 2024 and an estimated US$38 in 2025. For a dated live reading, Kitco showed a bid of US$56.98 per ounce at 14:50 New York time on 15 October 2026. That is about 1.5 times the USGS estimate for the 2025 average. Southern Copper’s silver sales rose in each of its three operating groups in 2025, as the chart in the company notes below shows.

Company notes: what each report says

Southern Copper. Silver mine production was 24.2 Moz in 2025, 21.0 Moz in 2024 and 18.4 Moz in 2023. By-product silver sales in 2025 were 13.2 Moz from its Mexican open-pit mines, 7.2 Moz from IMMSA and 6.5 Moz from its Peruvian operations, before an elimination of 2.9 Moz between units. The company reports 262.3 tonnes of refined silver from its refinery in 2025 (Southern Copper, 10-K for 2025).

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Southern Copper by-product silver sales by unit

Million troy ounces sold; IMMSA is an underground zinc-lead-copper-silver unit

KGHM. KGHM Polska Miedź reports 1,321 tonnes of silver in concentrate and 1,323 tonnes of metallic silver for 2025, while the group figure including foreign assets is 1,347 tonnes. The company lists staying among the world’s top three silver producers, at about 1,200 tonnes a year, as one of its strategic aims (KGHM, Q4 2025 presentation).

Hudbay. Consolidated silver in concentrate and doré, the impure gold-silver alloy poured at a mine, was 3,468,143 ounces in 2025 against 3,983,851 ounces in 2024, alongside 118,188 tonnes of copper. The Manitoba operations alone produced 800,198 ounces of silver in 2025 and were within their guidance range for silver (Hudbay, fourth-quarter 2025 release).

Glencore. Its copper department produced 9,281 thousand ounces of silver in 2025 against 8,569 thousand in 2024, while its zinc department produced 11,061 thousand ounces, which shows how much silver also sits in zinc and lead ore (Glencore, full-year 2025 production report).

What changed in silver supply from copper operations

The Silver Institute attributes the 3 percent rise in world mine output in 2025 to higher by-product output from copper operations in Peru and the ramp-up of the Prognoz mine in Russia. North American output fell 3 percent to its lowest level in 10 years, while supply from Central and South America rose 5 percent (Silver Institute, 15 April 2026). Lead and zinc mines remained the largest source of silver, but their share edged lower, while silver from gold operations grew 5 percent and from copper operations 6 percent. By definition, by-product silver is produced as the mine plan for the main metal is carried out.

How to read silver numbers in a copper project report

Technical reports and company filings give silver in several different ways. These checks avoid the common mistakes.

• Check the unit. Grades are given in g/t or ounces per short ton, and a troy ounce is 31.1035 grams. Contained metal is what is in the ground; recovered metal is what the plant is expected to produce.
• Look at the recovery for silver, not just copper. In the El Arco estimate above, copper recovery is 86 percent but silver recovery is 50.2 percent. Using the copper figure for silver overstates the ounces.
• See whether silver is in the reserve test. At El Arco, silver was left out of the pit optimisation. A deposit where silver changes the pit shell is a different kind of asset.
• Find the price used. Reserves are calculated at long-term prices set by the company, which may be far from the spot price. Compare silver and copper price assumptions in the same table.
• Separate reserves from resources. Reserves have passed economic tests; resources have not. A silver figure given only as a resource is not yet mine plan ounces.
• Read the sales terms. A concentrate buyer pays for the part of the silver that the contract counts as payable, which can be lower than the silver contained in the concentrate.

Finding silver-bearing copper ground before drilling

Satellites cannot see silver or copper grades. What they map is the rock around a porphyry system: iron-oxide staining, clay-rich alteration zones and structures. The USGS notes that remote-sensing techniques give insight into the crustal structure and magmatic framework that host mineralisation, alongside magnetic, seismic and gravity methods (USGS Scientific Investigations Report 2010-5070-B). Silver content has to be proved with samples and assays, and it is sensible to include silver in the assay suite from the first drill hole.

Farmonaut’s satellite-based mineral detection screens a licence boundary for copper and silver targets from satellite data, as an exploration target ahead of a resource estimate. It is a first screen, not a replacement for sampling.

▶ Explains what satellites can and cannot see when exploring for metals, and how they map the rock around a deposit. · 4:25

If this topic matters to you, read Silver as Byproduct of Copper, Lead & Zinc: The Real % next.

Frequently asked questions

Is silver a by-product of copper mining?

Yes. The USGS lists copper mines among the main by-product sources of silver, after lead-zinc mines and before gold mines in order of silver output. The silver is recovered with the copper concentrate and is separated in the refining stage.

How much of the world’s silver comes from copper mines?

The Silver Institute and Metals Focus show copper operations as one of the four source groups of silver mine supply, alongside lead-zinc, gold and primary silver mines, and report that silver from copper operations grew 6 percent in 2025, to 237.3 Moz, about 28 percent of the 846.6 Moz total. The USGS describes it more broadly: polymetallic ore deposits hold more than two-thirds of U.S. and world silver resources.

Which copper mines produce the most silver?

Company reports show large amounts at Southern Copper’s Peruvian and Mexican mines, at KGHM’s Polish operations, at Antamina and Collahuasi in Peru and Chile, and at Hudbay. Freeport-McMoRan’s Grasberg and Cerro Verde also produce silver. No single public ranking covers every mine on one definition, so compare the basis in each report.

How much silver is in a tonne of copper ore?

Usually a few grams or less. The El Arco sulfide reserve averages 1.8 g/t of silver alongside 0.40 percent copper, and the company expects to recover about half of the silver.

What is anode slime?

It is the sludge that collects in the bottom of an electrorefining tank when copper anodes dissolve. It holds most of the precious metals that were in the concentrate and is the feed for silver and gold refining.

Is silver on copper the same as silver-plated copper?

No. Silver plating is a thin silver coating placed on copper wire or parts for conductivity or appearance. This page is about silver that is mined together with copper.

Does silver make a copper mine more profitable?

It can, but the effect is usually modest. In the El Arco worked example the silver adds about 4 percent to the value of the recovered metal at the example prices. Molybdenum can supply a significant share of revenue at some mines (US EPA).

Can satellites find silver in copper deposits?

Not directly. Satellites map alteration and structure around a copper system, which help choose where to sample. Silver grade has to be measured with assays.

Why does silver output at one copper mine change from year to year?

Output moves with the part of the ore body being mined. Southern Copper attributes its 2025 rise in silver output to higher production at several mines, and Glencore’s share of Antamina silver rose 56 percent while its Collahuasi share fell 38 percent.