when a large deposit of tin was discovered in the Jos plateau in central Nigeria at the turn of the 20th century, expectations were high. Tin mining on the plateau began in 1905 and gradually became the backbone of the economic prosperity of Jos city. Jobs were easily available and the mining activities kept virtually everyone happy.
As the people basked in the economic boom brought on by the thriving tin mining industry, no one gave a thought to the environmental implications of the deep excavations. This resulted in environmental degradation of the landscape of Jos city, which was considered to be the most picturesque in Nigeria.
For about 67 years, the tin mining sector was virtually monopolised by foreign interests, particularly British firms that controlled 90 per cent of the tin mining industry. In 1972, the Nigerian government nationalised the industry. But the government action may have enabled the major culprits in the environmental degradation of Jos Plateau to evade responsibility for the costs of cleaning up the mess, say environmentalists.
The mined-out pits are filled with heavy metal-laden water, and high radiation levels are causing concern. No one is assuming responsibility for the massive clean up operation. People living on the plateau make use of the wastes from mining sites to build their houses, a practice which exposes them to radiation.
In some areas on the plateau, such as Bukuru, Rayfield, Shere Hills and Anglo Jos, deep ugly gashes -- reminders of the tin mining activities -- have inadvertently become reservoirs for effluents from industries. Ignorant farmers use it to irrigate their farms, unaware of the dangers of chemical poisoning. The presence of traces of tin ore and top soil that is washed into nearby streams and ponds from which nearby villagers get water for drinking and other domestic purposes is is a cause for concern.
Neither the numerous illegal miners who operate in self-discovered mines, nor the local companies that control most of the mining sites have the wherewithal to clean up the ecological mess on the plateau. Environmental activists, however, feel that the Nigerian government should provide the urgently-needed funds to redress nine decades of environmental degradation.
A survey conducted in the tin mining area of the city of Jos in 1976 found that about 316 sq km of the area of 86,000 sq km of the plateau had been damaged through mining activities. Various mining methods employed on the plateau, particularly the open cast mining for certain ores, have left a lunar landscape of steep-sided mounds and multi-coloured ponds or lakes, says another report compiled by the Ibadan-based Nigeria Environmental Study Action Team.
Experts say that the open cast mining is responsible for large-scale destruction of soil resources in the plateau. Using this method, miners often remove up to 15,000 m of overburden to reach the tin lode. It is estimated that annual soil loss on the plateau, principally due to open cast mining, is about 6,000,000 tonne.
The situation has worsened as the tin mining sector is going through a lean period. In the 1970s, tin ore output averaged at 10,000 tonnes annually. It fell to 3,000 tonnes in the '80s and to less than 500 tonnes since the beginning of the '90s.
Tin yield per cubic yard of ground has also fallen. In the early '70s, about 215704 cu m of ground yielded 100 tonnes of tin ore. In the '80s, the same area yielded 68 tonnes of tine ore. In recent years, tin ore yield per cubic metre of ground has dropped further.
As output per cubic metre fell, miners tore up more land to keep up the production level. About 80 per cent of Nigeria's tin produce is now derived from very deep levels, reaching an average of 33.5 to 36.5 m. In the early '70s, most of the tin was derived from shallower levels of about 16.7 m.