A Colombian sand miner dives under the water to extract sand from the bottom of the river La Vieja in Cartago, Colombia.

A Colombian sand miner dives under the water to extract sand from the bottom of the river La Vieja in Cartago, Colombia, 14 April 2013. Artisanal (unmechanised) sand mining is an ancient mining technique used to obtain sand for construction purposes. Depending on the natural conditions (strength of the stream, depth of the river etc.), together with the sand miners' physical condition, the material is extracted in metal buckets, either by standing on the river bottom and searching for sand by feet, or, diving up to 3-5 meters deep using a wooden plank with steps. In spite of the physically demanding work, a sand miner's daily salary does not exceed 15-20 US dollars. However, the sand miners are very proud of their profession, valuing their work freedom above all, and usually, as long as their health and strength permit, they keep facing the river stream.