From my childhood termite mounds fascinated me a lot. My city of Ranchi in Jharkhand State of India such mounds are very common. I used to imagine it as small mountain. Many scared me also saying that it is the house of poisonous snakes. Lots of imaginative stories I used to hear about this termite mounds. These increased my inquisitiveness.
At present, while on my way to college which is nearly 20 kms from my residence, I encounter several small to medium termite mounds in isolated places. Even in my college backyard there are few termite mounds.
Few years ago I came to know an interesting fact about these mounds that the soil of it is used for cosmetic purposes. But what attracted me a lot that such mounds are used as the pathfinder for prospecting precious metals like gold. The termite mounds serve as early indication as to what may be found in the soil below.
Termites are one of the most abundant animals on earth. They inhabit 2/3 of the lands surface, mostly in the tropical regions. They live on cellulose, which is why they eat homes. However, termites do not produce cellulases, the enzymes that break down cellulose. These enzymes are produced by protozoa in the termite gut that take in the ingested cellulose chips, digest them and produce acetate and other products that the termites can use for energy and carbon. The termite gut also contains a host of bacteria that use the protozoan products which are converted to methane. The methane contributes to global warming. Termites thrive in the deforested areas produced by man as he moves into the forests.
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. 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. To me in Jharkhand termites cannot go more than 30 to 40 feet because after that hard rock is present below.
That's why termites are fantastic gold prospectors; in fact, ancient African civilizations used the termite mounds to locate gold deposits.
In the ancient text of India Brihat Samhita (Sanskrit) written by Varahamihira (A.D. 505-587), pointed out that termite mound is an important bio-indicator of groundwater and economically important mineral deposits in the tropical lands generally covered by thick soil mantle. On the basis of the observations in the ancient and modern scientific literature, recent biogeochemical studies described these mounds in the tropics as an important tool in the exploration for chromium and copper and lead in India; and for gold in Zimbabwe, and copper and nickel in Mozambique in the African continent.
Jharkhand plateaus are said to be rich in gold deposits. Though the mechanized mining is not economical but still today the villagers are found panning for gold in the river basin of Swarnarekha river (Swarna means gold and rekha means line) and other rivers in Jharkhand State. Termite mounds are also very common in such areas.
As compared to other countries where termite mounds are being used as pathfinder for gold and diamond, people or mining companies of Jharkhand State still don’t know about this biogeochemical aspect of the mounds.
According to different reports, 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.
The technique is of old age in West Africa, where generations of gold diggers in pre-colonial times used the termites' labour to investigate the deeper layers of the soil for gold and other precious metals and minerals. The modern mining industry rediscovered the method in the 1960s, taking samples from termite mounds in the tropics and from anthills in other regions. Reinventing this ancient and cheap method, the Vila Manica copper deposit in Mozambique were discovered in 1973. Later, the biggest kimberlite (diamond) mine in the world - Jaweng in Botswana - was found by termite mound sampling. Several gold prospects in Southern Africa have since been discovered through the termite method, and a new science, termed "geo-zoology" has even been established to further develop the technique.
Termite mounds have been an inspiration for humans who want to mimic the fantastic ventilation system used in the termite structures. Hot air rises through tubes in the above ground mounds while winds from outside send air currents down into the subterranean chambers so temperature is regulated no matter the weather outside. This efficiency might be able to be put to use in the homes of people.
Termite mounds have been studied for use in road construction in Africa. The secretion used by termites to make the soil of their mounds hard is so effective that roads are being built using these same chemicals. The roads are cheaper and more durable than asphalt roads.
If a mound is damaged, it is immediately fixed to protect the colony, and the mounds are constantly remodeled, a process that also requires water. The termites clamp bits of clay or wet rock in their jaws, then climb back home to build the mound, grain by damp grain. The mound goes higher, because everything they dig is brought up to surface, including the hardest particles. In doing this they bring up samples from that depth.
If the mining companies concentrate on soil analysis of termite mounds in gold deposits areas like Tamar in Ranchi district and Singhbhum in Jharkhand state they are sure to get some encouraging results.
Thus, an analysis of the termite mounds can give a quick answer to the contents of deeper laying levels of soil and even rock.
Prasad, E.A.V., Gupta, M.J. and Dunn, C.E. 1987. Significance of termite mounds in gold exploration. Current Science, Vol.56, No.23, pp.1219.