[Proceedings of the VII international symposium 'Cultural heritage in geosciences, mining and metallurgy : libraries, archives, museums' : "Museums and their collections" held at the Nationaal Natuurhistorisch Museum Leiden (The Netherlands), 19-23 May, 2003 / Cor F. Winkler Prins and Stephen K. Donovan (editors)]: Written reports on the effects of mining activities on the natural environment in Idrija in the 19th Century

The environmental conditions in the Idrija Mercury Mine and its broader surroundings were strongly affected in the first half of the 19th century by two disastrous pit fires. The fire could only be extinguished by flooding of the pit. The consequences of such flooding was extensive poisoning with mercury vapours, not only among those miners who participated in the fire extinguishing effort and later in the rehabilitation of the pit, but also among the inhabitants of Idrija. During rehabilitation works, the highly polluted water was discharged directly into the Idrijca River, killing all the fish species thriving there. After 1835 the Mine gradually intensified its production. The dumping of increasingly larger quantities of smelting wastes directly into the Idrijca River considerably aggravated the environmental conditions in the river and along its banks. The Mine had begun to pay indemnities in 1788 to affected landowners in the vicinity of the smelting plant. The Mine Administration, supported by the competent ministry and the Higher Mining Office in Klagenfurt, rejected all accusations and proved, evidently with false data, that smelting gases did not contain mercury vapours and that smoke gases were not harmful. Only in 1881 did they finally begin to pay affected landowners a regular annual support in place of indemnity.