/sci/ - Science & Math

The exciting thing about mining undersea for me is in-situ ballast manufacture.

A really bizarre thing that isn't commonly known abut putting living space underwater is that a huge chunk of the expense is in making it heavy enough to sink. Every cubic foot of air needs 64lbs of ballast weight just to make it neutrally buoyant and two or three times more to securely emplace it on the ocean floor. This sounds trivial, after all pig iron ingots and other bulk ballast materials are cheap. But transporting them over land is not. You've got to move the habitat and the ballast, usually separately, via railroads because nothing else can carry the load, with cranes at either end for getting it on and off, and eventually putting it into the water. Then you tow it out to the site while it's floating, then boat small loads of ballast out a few at a time and start filling the ballast containers so the habitat will sink.

It's a huge pain in the ass that is totally overcome if you can use waste materials from mining as your ballast, and manufacture the habitats underwater. It's kind of the same rationale as mining in space in order to avoid having to push the product up out of Earth's gravity well, only in reverse.