Well it appears that Gold is now more lucrative than coca and the FARC rebels are busy taking advantage of the gold being mined in Columbia.  Here is a great story reported by  the BBC.

Rebels are now involved in legal and illegal gold mining.  A decade ago, the Colombian region of Putumayo was the main production centre for coca, the raw material for cocaine. And the guerrillas from the Revolutionary Armed Forces of Colombia (Farc) were well placed to profit from the illegal drugs trade. Today, there are still small fields of bright green coca cut from the virgin jungle, but the rebels have found a more lucrative, and far safer, source of income: gold.  It was here the US military aid package, known as Plan Colombia, which has amounted to some $8bn (£5bn) since 1999, was concentrated. Since 2000, fleets of spray planes have dropped glyphosate chemicals over the coca bushes, managing to reduce, but never eradicate, drug production.  What the chemicals have done is push local farmers into the new, informal industry of gold mining. “We estimate that the Farc here make 800m pesos ($450,000) a week from illegal gold mining,” said Jhimmy Calvache, the acting mayor of Mocoa in Putumayo province.