Before we get into mining in Rome, it’s important to first make it clear that metalworking was not invented in the Roman Empire. These techniques were very popular in Italy as early as the Bronze Age, around 53 BC.
However, the expansion of the Roman Empire meant that demand for metals was high and so more sources of ore needed to be found. Most metals mined in the Roman Empire, including all conquered territories, were used to support its large-scale military and infrastructure.
But gold in particular would grow to become the most central pillar of Roman civilization. It became not only the currency of the day but also a measure of wealth and the driving force of global trade.
Sources of gold in the Roman Empire
Gold mining in the Roman Empire began in 75 AD. However, central Italy, where the Roman Empire was based, was not particularly rich in gold or any other metal ore. As a result, the empire had to rely on conquered territories abroad for its supply of gold ore.
Gold was transported to Rome through a series of trade networks from various sources within the empire. Most of the gold used in Rome came from nine territories, including:
- Iberia, a peninsula in southwestern Europe including present-day Spain and Portugal
- Gaul, a region in Western Europe that included modern-day France, Belgium, Switzerland, and Luxembourg.
- Cisalpine Gaul, an independent administrative body of the Roman Empire in Italy
- Britannia, present-day England
- Noricum is largely in present-day Austria and parts of Slovenia
- Dalmatia, one of the historical regions of Croatia
- Moesia, a region in the present-day Balkans just south of the Danube River
- Arabian Peninsula
- Africa
Mining technology
The technology used to extract metals from ore in the Roman Empire was quite advanced at the time. The Romans smelted ore, a technology that continues to be used today. In its basic form, smelting is simply heating ore to create a molten liquid that separates the metal from the rest of the ore.
The Romans also developed casting technology that allowed them to cast metal into large blocks. However, the most commonly used gold extraction methods are cupellation and granulation.
You see, the gold mined in this region contains traces of copper and silver. For this reason, cupene is used as the first step in the gold mining process. Essentially, the process involves treating the ore with high temperatures, which separates traces of copper. This will leave traces of gold and silver.
The second step now is to separate the gold from the silver. This is where the seeds are created. Silver and gold ores will be heated until a molten liquid is formed. This liquid will then be poured into cold water from granules.
These particles are an alloy of gold and a modified form of silver scientifically known as Silver Chloride. The Romans would then melt the grains with salt, where they would separate the silver chloride from the gold.
The invention of hydraulic mining
Much of the mining for gold and other metals is done by hand. However, a method called the silent technique was invented, which massively increased mining yields. Silence is an ancient mining technology in which a stream of water is used to remove debris and expose mineral veins.
This technique is now commonly known as hydraulic mining. It was a game changer for the mining industry in Rome because it increased efficiency on a large scale. Additionally, the Romans’ ability to organize production through a comprehensive management structure meant they could mine gold and other metals on a large scale.
During peak mining, it is estimated that the Roman Empire would have produced up to 9 tons of gold per year. At today’s gold prices, this output would yield annual gold revenues of more than half a billion dollars.
Economic and social impact
Large-scale mining operations in Rome were not without social ramifications. For example, because mining at the time required a lot of labor, the use of slaves in the mines was common.
However, it reached a point where the cost of buying slaves became too high. As a result, the Romans introduced a system of indentured servitude in which people, especially convicts, were forced to work in mines without pay.
The economic impact of the mining industry was also felt throughout Rome. It is believed that the huge supply of metals from mines abroad was one of the most important factors that led to the expansion and survival of the Roman Empire. It is also believed that gold coins in particular influenced the development of international trade between Rome and distant countries such as India and China.
