An ancient cheap African method

Jan 15, 2007 14:52 GMT  ·  By

They may be also named "white ants", but termites are in fact related to ... cockroaches! ...

Termites eat on dead plant material, including wood, that's why 10% of the termite species are regarded as pests. In a few months, a termite colony can bring down a wooden house!

Termites are also known for their mounds, harboring the colony, made of clay combined with insects' saliva.

Termite mounds are found in tropical areas, especially dry savannas (Africa, Australia, South America) and are extremely elaborate.

They are considered the largest animal constructions related to the size of the constructors (as a termite has less than 2 cm, this is like people building something as high as Himalaya). The mounds can be up to 6 m (20 feet) tall above the earth, having different forms (mushroom, dome, conical and so on), but most of the colony is bellow the soil.

Mounds' orientation help in thermoregulation. The column of hot air rising in the above ground mounds helps drive air circulation currents inside the subterranean network.

Inside the mounds, temperature and humidity are constant, as the termites depend on fungi cultivated on dead matter they collect, and their culture requires constant conditions.

So, the industrious termites need to dig for water, and sometimes they search for water till depths of 75 m (225 feet) or hundreds of meters away; at the same time, their mound go higher, because everything they dig is brought up to surface, including the hardest particles. Thus, an analysis of the termite mounds can give a quick answer to the contents of deeper laying levels of soil and even rock.

That's why termites are fantastic gold prospectors; in fact, ancient African civilizations used the termite mounds to locate gold deposits.

Because they dig so deeply, termites can access the relatively unmodified rock and soil from which the thick tropical red clays develop. This parent material has not yet been exposed to the hard rains that wash out most minerals, including gold.

Some termite mounds can be so rich in gold that dissolving them and panning the slurry provides a significant side income for poorer residents of tropical regions. The unconventional "termite" technique is increasingly used by western companies looking for gold in Africa. Its advantages are obvious; there is less need for manpower and equipment, which has to be transported to remote areas, often without infrastructure, when the work is left to the termites.

In a prospected area, termite mounds are isolated, dug up and analyzed for gold.

The mounds are everywhere in the terrain and sampling and analyzing is cheap, about US$ 20.00 per sample. Using this method, gold prospects have been found in Southern Africa and several countries in western Africa, like Mali and Niger.

But termite mounds have been used not only for finding gold. The ancient and cheap method led to the discovery of the Vila Manica copper deposit in Mozambique in 1973.

Later, the biggest kimberlite (diamond) mine in the world - Jaweng in Botswana - was found by termite mound sampling.

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