Over the weekend, 32 miners were killed in an explosion at a coal mine in the northeastern Norte de Santander province, near the border with Venezuela, when combustible gas ignited. It was one of the country's worst mining disasters.
Many Colombian mines are makeshift with few or no safety procedures.
In January 2006, three self-employed coal miners died at a mine in northern Colombia after inhaling poisonous gases.
Other mine disasters in the country have been the result of landslides and erosion.
Coal is Colombia's second largest export after oil.