On 10 May 1897, twenty miners died at the Great Snaefell Mine in the Laxey Valley, the Isle of Man's worst mining disaster. An underground fire had smouldered unnoticed through the weekend, filling workings with odourless carbon monoxide; the early shift descended the shaft at 6am unaware of the danger and was overcome. The Great Snaefell Mining Company had worked the zinc mine, on the slopes of Snaefell in the parish of Lonan, since 1856; it was finally abandoned in 1909.