This week, officials at the site of a landslide that claimed dozens of miners in Tibet announced geological causes—including steep surfaces and broken rocks aggravated by meltwater—as reasons for the disaster.

The event took place March 29, burying 83 miners at Si Bu Village; mining operations nearby, however, were unaffected. So far, 59 bodies have been recovered amid repeated delays for 4,500 rescuers for fears of a further avalanche.

The avalanche originated at a precipitously long, narrow flow channel, as complex geology including protruding rocks had evolved—two critical elements accentuated by meltwater seepage after a dry season were followed by repeated snowfall, according to rescue officials.

The miners were employed by contractors for Tibet Huatailong Mining Development, a subsidiary of Canada’s China Gold International Resources; the Jiama copper-polymetallic mine production facilities lie 10 km away from the site.

Vancouver-based China Gold also operates the CSH gold mine in Inner Mongolia in northern China; Si Bu Village is 68 km from regional capital Lhasa.