In the previous instalment of Digging Deep, a rather outlandish theory of the origins of mining, suggesting that the activity was first undertaken by a race of alien miners some 400 000 years ago to exploit the earth’s gold resource, was postulated.
While this theory is fascinating and entertaining, it must be confined to the category of ‘alternative theories’, as the more mainstream hypothesis offers a more plausible explanation regarding why, when and by whom the extraction of the earth’s natural resources was first undertaken.
The earliest evidence of man’s mining activities – mining being defined as the removal of minerals from their natural geologic environment and their trans- portation to the point of processing or use – dates back to the Middle Stone Age, roughly 41 000 to 43 000 years ago.
It is believed that, during this period, primitive men, at least in Southern Africa, became acquainted with minerals such as hematite, specularite, and pyrolusite. These pigment minerals were found to be ideal cosmetic materials when ground down and were used for both cosmetic purposes and rituals, as well as for cave painting.
The oldest known mining site on archaeological record is the Lion Cavern, which is on a high ridge of the Ngwenya mountain range, on the north-western border of Swaziland.
According to archaeological investigations, which were initiated in 1964, when ancient tools were discovered at Anglo-American’s fledgling iron-ore mining operation in the Ngwenya mountain range, mining was first undertaken in the region around 41 000 BCE.
These investigations revealed that Middle Stone Age people tunnelled adits into the precipitous western face in search of iron pigments, including weathered hematite near the surface and specularite, the deeper and harder black glistening form of iron-ore. (Specularite has no surface oxidation and looks much like modern glitter and is believed to have been used for rituals.)
Radiocarbon dating of the charcoal nodules found in these ancient mines revealed that the iron resource at Ngwenya was exploited for some 20 000 years to around 23 000 BCE.
At the Lion Cavern, it is estimated that at least 1 200 to of soft hematite ore, rich in specularite, was removed in ancient times.
While the Lion Cavern may be the oldest known mine in the world, it is important to note that ochre was most certainly used some 100 000 years ago and evidence of the use of the pigment minerals by aboriginal peoples for cosmetic purposes and cave painting also exists in Australia, Europe and North America.
While man has been engaged in the activity of scavenging for and mining pigment minerals for more than 40 000 years, at least on a primitive scale, metal mining began less than 10 000 years ago and is, thus, a relatively new phenomenon.
To put this into perspective, in terms of the entire human evolutionary period, less than 5% of that time has been dominated by the age of metal mining and working, the remainder being the ages of wood and stone.
Interestingly, the age of metal mining precipitated the dawn of civilisation, a state of social develop- ment among humans marked by law and order and an organised effort to live peacefully.
One of the first metals exploited by primitive man was gold, owing to the fact that it exists in nature in an elemental state and was, thus, ready for use.
Alluvial gold would have been present in many of the river and stream systems the world over – the pretty glint of native gold embedded in river gravel would have caught the eye of primitive man and aroused his curiosity. To him, a nugget of gold was a soft stone of a peculiar and attractive kind and he soon discovered that, owing to its soft, malleable nature, the metal could be easily hammered into a ring or a bangle.
It is impossible to know exactly when humans started mining gold, but some of the oldest known gold artifacts have been found in the Varna Necropolis, in Bulgaria, which were made between 4700 BCE and 4200 BCE.
Copper was the other metal that was exploited in ancient times. Like gold, it is ductile and tenacious and, when freshly hammered, it resembles gold in colour and brightness.
It is probable that, once man had learned to look for nuggets of gold along streams, he noticed nodules of copper and treated both metals alike – as maelleable stones to be hammered into ornaments first and implements later.
Some of the oldest copper mines have been discovered along Lake Superior, in Canada, and it is believed that native Indians availed themselves of this copper from around 5 000 years ago.
The art of metallurgy – which entails shaping metals through the process of casting – followed the discovery of copper and probably sprang from an accident, like many other epoch- making discoveries.
A stone on the edge of a hot campfire may have contained some native copper, which was melted. If the stone contained an oxide or a carbonate of copper, it may have been reduced, in the presence of charcoal, by the heat of the fire. The next step was to make a hole for the collection of the molten metal, which was eventually lined with clay, the fire-resisting quality of which had been proved previously by the use of pottery.
Man living in ancient times, thus, ascertained that metal would run in a hot fire, just like fat or wax. Next, he noted that, on cooling, the molten metal retained the form of the surface on which it was poured.
The earliest moulds were cut in stone and the metal was poured into it.
Interestingly, the first evidence of human metallurgy was discovered in Serbia and dates from the fifth century BCE.