In 2009 I made my second visit to Sierra Leone in search of diamonds.Sierra Leone, in west Africa is one of the great sources of diamonds in West Africa. Unlike South African deposits, the diamonds of Sierra Leone, are typically found closer to the earths surface. As such, many small artisinal mines exist throughout the country.
Much of Sierra Leone's diamond deposits were initially found in the rivers - washed down from the kimberlite volcanoes which 100 million years ago, brought them out of the earth. These rivers, while less productive than before, still are a major area of mining activities. Often, miners have moved from just mining in the rivers, to mining the banks of the rivers, dried up river beds, and ancient swamp areas.
Mechanization is of course, a more practical way forward with mining. However it's not fool proof, and tends to increase costs enormously. One of the big issues are repairs to machinery - which is always breaking down, and of course, diesel gasoline.