According to one congressman, staffing at the National Geology and Mining Service, the industry regulator, has not increased much since it was founded in 1980, despite a fivefold increase in the output of copper in that period.

ECONOMIST: Chile's mine rescue

With such approach, natural anomalies can be assessed in relation to those caused by mining and related industrial activity, taking into account the geology, topography, climate, vegetation and hydrology in different regions of Africa.

UNESCO: EARTH SCIENCES FOR SOCIETY

Mine bosses blame their losses on lack of investment and awkward geology, but a report by a British firm called International Mining Consultants cites overmanning and bad management.

ECONOMIST: Ukraine