Terrament is patenting a number of different designs which enable us to maximize both height and weight to nearly 100% of a mine shaft. When you think about the physics of suspending thousands of tons inside a mile deep hole, the devil is in the details. To paraphrase Boromir, One does not simply hang a mile of concrete and steel from a cable ;) There are already some videos on the website that give away some details. We're waiting to secure funding before sharing the rest.

edit: oh sorry, I think you meant gravitricity sorry. I'm not sure what they're patenting. Also I don't think their patents are in the US.