To reach their claims, coltan miners walk for hours or days.

Miners remove the surface of the earth with picks looking for coltan.

Miners use their hands to scratch in the earth and select the stones that look like coltan.

Venezuelan soldiers seized machinery that was allegedly used to exploit columbite (a component of coltan).

Miners weigh the stones with their hands to distinguish coltan from other minerals. Coltan is almost black and weighs more.

Coltan is smuggled across the Orinoco river, which marks part of the border between Venezuela and Colombia.

One of the ways for Venezuelan smuggled coltan to reach Colombia is through Puerto Carreño.

Motorboats arrive in Puerto Carreño, Colombia, from port of El Burro in Venezuela. Citizens cross the border easily; they only need an identity card.