Diamond Mining in Sierra Leone

It is quite interesting to know about rough Diamonds Mining and that how it is done ?

This is a movie about diamond mining in Africa; Sierra Leone. Since the civil war of Africa / the Sierra Leone diamond industry is known as the source for the so called "Blood Diamonds".
 Diamonds that were mined under forced condition and traded on the illegal markets to purchase weapons. 

one of the source is Alluvial Deposits, extracted from the streams. not like Kimberlites which is in hard rocks.