Metal Age
Mining and Smelting of
Iron & Copper in the Lowveld
Some of the oldest known fragments of the earth's surface are found
in this area. They are granite-greenstone formations that crystallised
between 3.5 billion and 2.7 billion years ago.
Now known as the
Murchison and Sutherland Ranges, these formations reveal not only
some of the secrets of the beginning of life, but contain a wealth
of minerals including abundant deposits of iron- and copper- bearing
ores. More on the geology of the region is
here.
Iron and copper were the first metals extracted from ores,
used principally for weapons and hoes, and the making of ornaments
and jewellery respectively. European pre-history divides this period
into the Ages of Bronze (copper and tin) and Iron.
First Millennium Bantu settlements and related industries in the central lowveld
As both metals were extracted concurrently in this region, African
historians refer instead to the Metal Age, a pre-historic period
(in the European tradition) spanning nearly 2,000 years. It is not
clear when the trade ceased in the Central Lowveld. Certainly in
the Zoutpansberg region to the north iron smelting using the historical
process was still practiced in 1893.
Archaeological remains of furnaces
help us to interpret the methods that metalworkers used; these are
described in the section below. Little other ephemera from this
civilisation is available to help us imagine life in the Metal Age
besides fragmentary evidence.
Masorini museum site: A reconstructed iron age site in the Kruger Park close to the Phalaborwa mine
It seems from their pottery that the inhabitants described in the
Stone Age section continued to come into
the region from the north, in two distinct streams with different
artisanal traditions revealed by the fragments.
They were most likely
herders, and to a lesser extent tillers as the metal-making technologies
began to take hold. They certainly brought with them sorghum, a
highly resilient cereal crop used for making of mealie pap. The
first stone and retaining walls were built in this period. To protect
their livestock against marauding wild animals these people built
stockades made of tall poles armoured with branches of thorntrees.
Iron smelting and foundries
Smelting sites were scattered throughout the district but concentrated
near settlements, usually located between hills and on the lower
third of a koppie or on sites difficult to access and hidden from
prying human eyes. Furnaces were erected under large trees or a
specially-built thatched canopy. Big stones with flat surfaces,
wooden or bark troughs, or large clay pots sat close by, and contained
charcoal, water and the other necessary smelting process ingredients.
Also close by would be a smithy and and area where clay could be
mixed, both for the repair of the furnace, after each discharge
of smelt, and the manufacture of piping for the passage of air from
the bellows to the furnace bed. Archaeological evidence provides
our only reliable facts as to how ores were turned into metal. No
detailed eye witness accounts of the entire process remain: iron-workers
were treated with some suspicion by many tribes, especially those
who had strong ties with cattle.
Foundry in the Soutpansberg (Venda district 1890s) similar to those used at Phalaborwa
Source: "The Life of a South African Tribe"; H Gros; Macmillan, 1927
The metalworkers had to live apart from their hosts and were accepted
only grudgingly for their sought-after products. The metal-workers
themselves fuelled this suspicion by being secretive about their trade
in the interests of preventing others from replicating their magic.
It seems that groups moved around between tribes in search of orders
for metal.
Oral tradition suggests that numerous taboos and sacrifices
had to be observed before and during the smelting process; certain
other tribes specialised in ensuring the observance of these traditions,
possible only because to certain tribes any involvement whatsoever
with the process (apart from the end product) was cultural anathema.
It also seems that unwrought iron was traded by the smelters to the
smiths, who were not necessarily of the same clan and tribe.
Remains of furnace found at the Masorini Museum site in the Kruger Park
A variety
of iron ores were mined in open cast diggings. Stones containing a high percentage of the metal were collected in
river beds and from streams. These were broken to a suitable size,
about the size of a hen's egg, and carried to the smelting site.
The furnace was constructed of clay, often built into, or using material
removed from, termite mounds. Within this furnace would be metre high
smelting ovens, each resembling a cone with a 75cm base tapering into
a point with three equidistant slits down the side.
Alternate layers
of charcoal and ore would be packed into these ovens, and grass and
twig tinder used to sustain a flame started by rubbing a hard stick
into a softer one. All the layers would be lit at once, and bellows
applied to the slits to encourage the flame.
These bellows were ingeniously
manufactured from the entire hide of an antelope, removed from the
carcass in such a way as to minimise the number of holes cut into
it, and attached to wooden sticks that simultaneously enables the
skin bag to be compressed, and acted as a valve as air was being forced
out of it.
Smithing sites reconstructed on the Masorini hill site, Kruger National Park
It can be assumed that the smelting process took place after sunset
under the cover of darkness. It is possible that the three workers
(one per slit, each with two bellows) sang songs or worked to the
rhythm of a stone being beaten by a fourth person who monitored the
progress inside the oven by the colour of the material inside. He
would add a "flux" to prevent oxidation of the melting ore
which would be finely ground bones, lime, ash from certain trees,
salt or quartz sand.
The resultant melt, the "bloom", cooled
off and was then crushed using large rocks before embedded impurities
were removed and the metal was shaped by repeated heating and hammering
in a smaller charcoal fire. This also added carbon back into the melt,
turning into a steel.
Ingots and hoes were shaped by the smithy and,
at a similar size and weight, were accepted as a standard price in
barter for husbandry, animals, grain or spear blades, and indeed in
the settlement of marriage dowries (lobola).
Well preserved hoe blade, unused and kept as A ‘Lobola’ tribute. Collected by John Williams in the Sekororo district, 1989
