[redprince]

The tailings from the Bayer process for extracting aluminium oxide from bauxite aren't toxic. The remains ("red mud") have an elevated pH from the residual sodium hydroxide used in the extraction of the ore but that's about it. There's a lot of it though and that sheer amount makes it a bit of an environmental problem as Red Mud has limited industrial use and much of it will be dumped / stored somewhere.