At an open-cast mine, Abdullahi Ibrahim Danjija carefully chisels away at a hunk of whitish rock before stuffing a sack with the pieces which break off the walls.
In the course of a day's work he manages to fill three 50-kilo bags which will net him 150,000 nairas ($100), or around double the monthly minimum wage in Nigeria, Africa's most populous nation where more than one in two live below the poverty line.
