# Gold: Extraction

From cyanide heaps to doré bars at the mine

Source page: https://www.materialinsights.org/commodities/gold/extraction/

What this tab covers How it is mined, drilled or grown, and processed into a tradeable form: the main methods compared, their unit economics, by-products, and the companies that do this work globally and in India.

Gold occurs in quartz-vein lode deposits, in disseminated low-grade orebodies such as Nevada's Carlin Trend, in river placers, and as a by-product of porphyry copper. Most ore is crushed and leached with cyanide in tanks or on heaps, recovered on carbon and smelted into doré, a mixed gold-silver bar sent for refining. In the US, Nevada supplied about 64% of 2025 mine output, and about 7% came as a by-product of base-metal ores. Worldwide, an estimated 15% of gold is a by-product. Artisanal mining, often using mercury, adds a large informal share in Africa and Latin America.

Gold reaches the market by four routes. Most comes from large open-pit or underground lode mines that grind ore and dissolve gold with cyanide in tanks. Low-grade oxide ore is stacked on heaps and sprayed with cyanide instead, which is cheaper but recovers less. A sizeable share is a by-product of copper mines, where gold rides in copper concentrate to smelters. Artisanal miners, often using mercury, add a large informal share in Africa, Latin America and Asia. Recycling of jewellery and scrap is the fifth source and, unlike mining, responds within weeks to price. All routes end at a refinery that produces bars to LBMA or exchange standards.

#### Methods compared

| Method | Share of supply | Typical scale | Recovery / efficiency | By-products | Unit cost |
|---|---|---|---|---|---|
| **Open-pit and underground lode mining + carbon-in-leach (CIL/CIP)** | most of the 3,300 t mined in 2025 (USGS); no split by method is published | large mines produce 0.3-1 Moz a year; Newmont's whole portfolio produced 5.9 Moz in 2025 | typically above 90% for free-milling ore; lower for refractory ore (indicative) | silver, sometimes copper | AISC 2025: Agnico Eagle $1,339/oz, Barrick $1,637/oz, Gold Fields $1,645/oz |
| **Heap leaching of low-grade oxide ore** | n/a | ore grades often below 1 g/t (indicative) | about 50-80% (indicative) | silver | n/a |
| **By-product of copper and base-metal mining** | about 15% of world gold is a by-product (companionality); about 7% of US output in 2025 | porphyry ore often 0.1-1 g/t Au alongside 0.4-1% Cu (indicative) | n/a | gold is the by-product; copper, molybdenum and silver are co-products | gold credits often push copper mines' net cash cost down sharply; no separate gold cost |
| **Artisanal and small-scale gold mining (ASGM)** | a significant informal share; WGC's 3,672 t mine figure exceeds USGS's 3,300 t partly for this reason | kilograms to tonnes per site per year | often low with mercury amalgamation (indicative) | n/a | n/a |
| **Recycling of jewellery and industrial scrap** | 1,404 t in 2025, 28% of total supply | India 21.7 t in 2025 | near complete for jewellery scrap | silver, copper | refining charges are a small fraction of metal value |

#### How each method works
**Open-pit and underground lode mining + carbon-in-leach (CIL/CIP)**

Ore is crushed and ground to a fine slurry. Cyanide dissolves the gold in agitated tanks and activated carbon adsorbs it. Carbon is stripped, gold is electrowon and smelted into dore. Refractory sulphide ore needs roasting, pressure oxidation or bio-oxidation first.

High recovery and scale; high capital cost, cyanide handling and tailings dams.
 Company FY2025 results (Agnico Eagle, Barrick, Gold Fields); recovery: Marsden and House, The Chemistry of Gold Extraction (indicative) **Heap leaching of low-grade oxide ore**

Run-of-mine or crushed ore is stacked on lined pads and irrigated with dilute cyanide for weeks to months. Pregnant solution is collected and gold is recovered on carbon. Used widely in Nevada, Mexico and West Africa.

Low capital and fast to build; lower recovery and slow leach cycles, weather sensitive.
 Marsden and House, The Chemistry of Gold Extraction (indicative ranges); no published share or cost found **By-product of copper and base-metal mining**

Gold in porphyry copper ore floats with copper minerals into concentrate. Smelters pay for the gold, which is recovered from anode slimes in copper refineries. Grasberg, Oyu Tolgoi and Chilean porphyries are large examples.

Supply set by copper economics, not gold price; very large orebodies.
 Nassar, Graedel and Harper (2015), Science Advances; USGS MCS 2026, Gold **Artisanal and small-scale gold mining (ASGM)**

Individuals and small crews dig alluvial or shallow hard-rock ore, crush it by hand or with small mills, and amalgamate gold with mercury, then burn off the mercury. Output often moves through informal traders to Dubai and other hubs.

Livelihoods for millions; mercury pollution, child labour, smuggling and conflict finance risks.
 WGC Gold Demand Trends FY2025; USGS MCS 2026 (production comparison) **Recycling of jewellery and industrial scrap**

Refiners melt and assay old jewellery, dental gold and electronic scrap, then refine to bullion. Jewellery is most of it. In India, much old gold is exchanged at the jeweller for new pieces.

Price-responsive within weeks; depends on households choosing to sell.
 World Gold Council, Gold Demand Trends Full Year 2025 (Jan 2026); WGC India data as reported by Outlook Money (Jan 2026) Unit economics are indicative ranges from the sources named; costs vary widely by deposit, region and year.

#### Share produced as a by-product
 About 15% of primary supply comes as a by-product (Nassar, Graedel & Harper 2015, approximate).

#### Who does it: global

| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| **Newmont** The results release could not be re-read for this check; figure as first recorded from it. | US | mining | 5.889 Moz attributable gold | 2025 | [Newmont Q4 and full-year 2025 results release (19 Feb 2026)](https://secure.businesswire.com/news/home/20260219222644/en/Newmont-Reports-Fourth-Quarter-and-Full-Year-2025-Results-Provides-2026-Guidance-and-Announces-Enhanced-Capital-Allocation-Framework) |
| **Agnico Eagle Mines** | Canada | mining | 3.45 Moz gold | 2025 | [Agnico Eagle Q4 2025 results, as reported by Kitco (12 Feb 2026)](https://www.kitco.com/news/article/2026-02-12/agnico-eagle-posts-record-free-cash-flow-2025-higher-gold-prices-drive) |
| **Barrick Mining** | Canada | mining (gold and copper) | 3.26 Moz attributable gold | 2025 | [Barrick full-year 2025 results (Form 6-K)](https://www.sec.gov/Archives/edgar/data/756894/000119312526039501/d10712dex991.htm) |
| **Zijin Mining** | China | mining (gold, copper, silver) | 90 t mined gold | 2025 | [Zijin 2025 results, as reported by Mysteel](https://www.mysteel.net/news/5116826-flash-zijin-mining-posts-6155-surge-in-2025-net-profit-driven-by-record-copper-and-gold-output) |
| **Polyus** | Russia | mining | 2.529 Moz gold | 2025 | [Polyus financial and operating results for 2H and FY2025](https://polyus.com/en/media/press-releases/proizvodstvennye-i-finansovye-rezultaty-za-2-polugodie-2025-i-2025-god/) |
| **Gold Fields** | South Africa | mining | 2.44 Moz attributable gold-equivalent | 2025 | [Gold Fields 2025 results, as reported by Mining Weekly (19 Feb 2026)](https://www.miningweekly.com/article/gold-fields-lifts-shareholder-returns-after-strong-2025-financial-performance-2026-02-19) |

#### Who does it: India

| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| **Hutti Gold Mines Company (Karnataka govt)** | India | mining (underground, Hutti and Uti) | 1,302 kg gold (India primary gold output, almost all from Hutti) | FY2026 | [Ministry of Mines Annual Report 2025-26, as cited by ClarityUPSC](https://clarityupsc.com/news/article/hutti-gold-mines-hgml-karnataka-gold-production-3033) |
| **MMTC-PAMP India** | India | refining (LBMA-accredited, Haryana) | 80 t gold refined (more than) | FY2026 | [ICRA rating rationale, 28 Jul 2026 (capacity 300 t gold, 600 t silver a year)](https://www.icra.in/Rating/ShowRationalReportFilePdfViewer/144567) |
| **Reserve Bank of India** | India | official reserve holder | 881 t gold held (about 680 t in India) | end-March 2026 | [RBI half-yearly report on management of forex reserves, as reported by Angel One](https://oga-prod.angelone.in/news/economy/rbi-brought-back-77-of-gold-reserves-as-global-risk-drives-shift-to-domestic-holdings) |

India mines almost no gold: Hutti produces about 1-2 t a year against demand of 710.9 t in 2025 (WGC). The country is the second-largest consumer and imported 721 t worth $72.0 billion in FY2025-26. Value is added in refining (MMTC-PAMP and others) and jewellery making.

## Other sections

- [Summary](https://www.materialinsights.org/commodities/gold/index.md)
- [Overview](https://www.materialinsights.org/commodities/gold/overview/index.md)
- [Correlation](https://www.materialinsights.org/commodities/gold/correlation/index.md)
- [Production](https://www.materialinsights.org/commodities/gold/production/index.md)
- [Stocks](https://www.materialinsights.org/commodities/gold/stocks/index.md)
- [Cycles](https://www.materialinsights.org/commodities/gold/cycles/index.md)
- [Trading](https://www.materialinsights.org/commodities/gold/trading/index.md)
- [Movement](https://www.materialinsights.org/commodities/gold/movement/index.md)
- [Criticality](https://www.materialinsights.org/commodities/gold/criticality/index.md)
- [Characteristics](https://www.materialinsights.org/commodities/gold/characteristics/index.md)
- [Emissions](https://www.materialinsights.org/commodities/gold/emissions/index.md)
- [Relationships](https://www.materialinsights.org/commodities/gold/links/index.md)