Dore Bar
Also: Dore, Dore Bullion, mine bar
Dore bars are pre-refined crude bars of gold and silver, cast directly at mines or smelters and subsequently processed to fine-metal quality at a refinery.
Dore bars (from French doré = gilded) are the immediate product of pyrometallurgical processing at gold and silver mines. After the barren rock has been broken down by cyanide leaching or other processes, the enriched precious metals are melted down and cast into crude bars on site. These bars leave the mine and pass to the refinery, where they are refined to tradeable fine-metal quality (≥ 995‰ for LBMA Good Delivery, often up to 999.9‰ fine gold).
Composition and production
A dore bar is not a pure precious metal but an intermediate product with variable fineness. Depending on the deposit and processing method, it contains:
| Component | Typical range |
|---|---|
| Gold | 60–95 % |
| Silver | 5–35 % |
| Impurities (Cu, Pb, Zn …) | < 5 % |
The yield of gold and silver from a dore bar depends on the exact fineness, which is determined by sampling (assay) before affinage.
From mine shaft to market
- Ore extraction — mining in open pit or underground (primary mining).
- Processing — grinding, flotation, leaching; precious metals are brought into solution.
- Melting — precipitation and melting into a dore bar directly on the mine site.
- Transport & assay — secure transport to the refinery; sampling determines the exact content.
- Affinage — electrochemical or chemical refining yields fine gold (999.9) and fine silver.
- Trade — the refined metal flows into bullion bars, coins or industrial applications; the current gold price and silver price serve as the settlement basis.
Significance for the gold market
Around 90 % of annual mine production reaches refineries as dore bars. The difference between the spot price of fine gold and the refining costs (treatment and refining charges, TC/RC) determines the revenue side of the mining company. With the Melt Value Calculator the notional metal value of a crude bar can be estimated from weight and fineness.
Dore bars are not a trading object for private investors — they meet neither the LBMA Good Delivery requirements nor the conditions for VAT-exempt investment gold. For the price development of historical precious-metal prices, however, they are a central supply factor.
In brief
Dore bars form the link between mine production and the fine-metal market: only after refining at an accredited refinery does the tradeable fine metal arise that corresponds to the global gold price.