In the Canton of Glarus, Switzerland, public education became compulsory around 1875. Slates were required as writing tablets for the students, leading to a sudden uptick in business at the local slate mine in Elm. Seeing the possibility for a quick profit, local farmers bought into the mine and began digging, furiously.
Not one of them knew anything about mining, or paid any heed to the quarriers, and in their eagerness to extract the maximum from the mine as quickly as possible, dug into the mountain 65 meters deep along a seam of 180 meters, without proper support. Their ignorance led to one of the biggest disasters in that area:
There had been warning tremors and increased rock-fall for days, but on Sept 11, 1881, starting at noon and over several hours, ten million cubic meters of rock broke off and thundered 500 meters to the valley floor. The momentum and the mass were so immense that rock debris landed up 100 meters on the other side of the valley bottom. Ultimately it extended 2 kilometers down-valley, covering 222 acres of farmland and destroying 83 buildings. One hundred and four people were killed and the mine was completely destroyed. That was the end of slate mining in that area.
There is a novel by the Swiss author Franz Hohler about the disaster at Elm (“Die Steinflut”) It was translated into English and issued by Havil, London in 2001 as “The Stone Flood”. It’s a good read!