Mining had far-reaching ecological consequences throughout much of colonial Spanish America. It deformed the landscape, introduced pollutants such as sulfur, mercury and salt into the biosphere, and caused human settlement of sparsely populated or uninhabited regions. Forests succumbed to the charcoal makers' axes. Workers' lungs filled with silicosis-causing dust. Cave-ins snuffed out lives or crippled those they spared.
As unhealthy as mining was elsewhere in Spanish America, it was reported to have been especially harmful in the central Andes at Huancavelica. Workers there suffered the common diseases and injuries associated with the industry such as respiratory disease and broken limbs. They also had to overcome the challenges of arduous labor at high altitude. Most pernicious of all was the toxic nature of the mercury they were mining. Colonial critics asserted that Huancavelica was an environmental tragedy that placed workers in exceptionally dangerous conditions in order to produce the mercury needed by silver refiners to amalgamate and refine their ores. The critics claimed that the mercury mines' human cost was immoral, yet their cries of despair and outrage could not overcome quicksilver's crucial importance to the imperial economy. Killing and maiming, Huancavelica earned for itself an infamous reputation as the mina de la muerte (the mine of death).