The [tunnel’s] accelerants cure the grout that seals the tunnel’s concrete supports, helping the grout set properly and protecting the work against cracks and other deterioration. They also seriously burn exposed human skin. At the Encore dig site, such burns became almost routine, workers there told Nevada’s Occupational Safety and Health Administration. An investigation by the state OSHA, which Bloomberg Businessweek has obtained via a freedom of information request, describes workers being scarred permanently on their arms and legs. According to the investigation, at least one employee took a direct hit to the face. In an interview with Businessweek, one of the tunnel workers recalls the feeling of exposure to the chemicals: “You’d be like, ‘Why am I on fire?’”
He thinks he knows how to build a colony on Mars better than anyone. He hasn’t considered that maybe there are good reasons why it hasn’t been done yet. His first colony will be a death trap.
That’s a feature, not a bug. His family got rich with mines in south africa, exploiting the locals. For getting more rich by mining mars you’ll have to bring your own locals to exploit, and there’s no need to make it to comfortable for them.
He’s planning it mostly as a one-way trip, sort of a “live the rest of your life taming the wilderness” pitch. It isn’t all that different from the colonizing that went on Earth, and even the casualties might not be much higher.