the range of products that man could develop and so opened up another avenue for social and economic advance.
3. The Iron Age
With the coming of the Iron Age, the final period of pre-history, mining took a step forward, certainly as far as efficiency was concerned. One of the problems with earlier mining was the fact that stone implements were the main tools for digging and breaking rock, and they were not particularly robust and were thus prone to become unusable quickly. Bronze was too valuable and too soft to be a realistic substitute in the making of such heavy-duty tools, but the coming of iron introduced an altogether tougher and more durable metal, ideal for tool making. The Iron Age brought to four the number of important metallic compounds that could be used to make weapons and other durable tools – namely copper, brass, bronze and iron. These proved of material help in the advancement of civilisation, particularly in the hands of the Romans.
The Iron Age itself, like previous ages, emerged in staggered sequence – in the 12th century BC in Greece and the Near and Middle East; a century later in India; and between the 8th and 6th centuries BC in the rest of Europe, with central and southern Europe ahead of the north. But iron was known and used in small quantities many centuries before that, with the earliest use being in the 4th millennium BC by the Egyptians. We have also seen that meteorites rich in iron were the source that ancient Egyptians tapped for the limited iron objects that they fashioned – spear tips for example. Much of this use of iron was ornamental and in no sense was iron widely used to make primary products such as tools and weapons. It was also more expensive than gold in those times because of its rarity, and also was viewed by some as a metal sent from the gods (it came out of the sky after all) and therefore sacred.
Once conventional sources of iron ore were found, which proved far easier to work than the earlier meteorite sources, the possibilities for making iron objects multiplied. The earliest method of turning ore into iron metal was to combine it with carbon and then melt the treated ore in a basic furnace until it became a spongy mass – sponge iron. The iron was then beaten with hammers and folded until all the carbon was released through oxidisation. The resulting product was wrought iron with very little in the way of impurities. Further heating of the wrought iron in charcoal, followed by water-cooling, produced a harder metal due to the process which added a steel surface to the wrought iron. Whilst this process did not completely achieve the hard finished product that was to follow through the making of cast iron, the ability to achieve the sponge iron stage did mean that, with relatively low temperatures in the early furnaces, an iron product could still be made.
The first objects made from mined iron ore came from Anatolia in the 12th century BC and this spread throughout the Middle East, and it was from here that it is thought iron ore mining and iron making spread to China where wrought iron objects made in the 8th century BC have been found in the north west of the country near Xinjiang. Sources of iron ore were reasonably available once the technology for making finished iron had been mastered. In the 5th century BC, during the Zhou Dynasty, kiln technology was developed which enabled the iron ore to be heated to much higher temperatures than formerly, which led to the manufacture of cast iron. The technology had spread to India by the 2nd century BC.
4. China
In the latter years of the 20th century and the opening decade of the 21st, one of the most dramatic developments affecting the global economy has been the rise of China to economic superpower status. However, China’s position as an economic power goes back millennia and along with this goes an equally long history of mining. China’s reputation as a centre for inventions and thus technological advance is well deserved, with paper, printing, gunpowder and the compass as four important examples. Paper was invented early in the 1st century AD in the Han Dynasty, and the other three items appeared in the middle of the 11th century, just before the cut-off date used in this book when we move from the Ancient World to the Middle Ages. These four were, though, inventions where metals had only a minor role.
It is interesting to note that in those ancient times China was responsible for the development of a considerable number of technologies that were metal related and this underpinned its position then as one of the most developed, if somewhat opaque, countries in the world. Amongst those inventions that benefited from the advances made possible by the working of metals were crossbows and arrows from the 5th century BC, and a rather sophisticated bronze steamer from the 10th century BC. Nearer the millennium, around 200 BC, a number of technical advances were made by the Chinese in the area of iron smelting, leading to the co-fusion process for making rudimentary steel in the 6th century AD.
Archaeological investigations have provided some broad parameters regarding the development of metal use in ancient China. One or two objects have been found that suggest the usage of metals in China in the 3rd millennium BC, but the evidence is not conclusive. Copper artefacts found in the north east of China in Shandong and Inner Mongolia provinces date from the Longshan Dynasty in the 2nd millennium BC. Bronze metallurgy existed in the Shang Dynasty in the latter part of the 2nd millennium BC, and it has been suggested that the Chinese may have in part skipped the copper age and gone straight to bronze due to their early appreciation of the results of alloying tin with copper.
Written records of historical Chinese mining are small in number, partly as a result of the country’s social hierarchy system which meant that mining was not considered an activity for the educated. Mines tended to be owned by rich landowners and although as the 1st millennium AD progressed mining was one of China’s most important industries behind agriculture and textiles, the landowning class did not get involved in it directly. So prospective ground was developed and the mine workings were leased to interested parties, with the landowner taking a rent or profit share from the operator but staying well clear of the business of mining.
The upshot of this disinterested attitude was that as little capital as possible was employed in the mines, which consequently were dangerous with poor working conditions. Mines were also mostly small scale and labour was both plentiful and cheap, so there was little incentive for mine owners and operators to spend much capital in upgrading working methods. Interestingly, the workforce often contained women and children.
Though China invented gunpowder there are no signs that it was deployed in ancient mining – for centuries rock continued to be broken using fire setting and basic leverage tools. Exploration was also fairly rudimentary, with traditional cultural techniques such as divining and fengshui being used, along with more scientific methods such as looking for surface indications of mineralisation, promising outcrop features and even associated plant growth.
Mining at Tonglushan
One of the best preserved of the ancient Chinese mining sites is Tonglushan, a copper mining area only a few miles from Huangshi in Hubei Province, dating back at least 3000 years to the 1st millennium BC. This area is still a substantial producer of a wide range of metals today but its ancient expertise was in the mining and smelting of copper ores.
The methods used by the Chinese in mining beneath Tonglu Mountain, where the rich copper ore lay, appear to have been quite sophisticated. Substantial numbers of shafts were sunk to access the ore, and drives and tunnels were constructed to transport the ore to the numerous smelting furnaces attached to the mining operation. Some of the tunnels were also used for bringing water to the workings, as well as removing water table inflows caused by some shafts having been sunk below the water table’s level. The mines were worked between 1000 BC, the time of the Western Zhou Dynasty, and the early part of the 1st century BC, the time of the Han Dynasty. It is estimated that Tonglu Mountain could have produced between 80,000 and 120,000 tonnes of copper over this long period.
In 2007 extensive sampling of lake sediments from Liangzhi Lake near Tonglushan threw more light on the history of mining in this province. A study, written following this exercise, suggests that before
