Combined Arms Mining Company originated as a small conglomerate of mining companies that attempted to set itself up as a rival to the ever-growing General Mining Corporation. Originally a joint venture between five companies, this had grown to 25 by the Human-Covenant War as more and more found themselves unable to compete with General Mining.
However, after the war, an opportunity to reestablish Combined Arms as a more powerful company presented itself. The Unggoy and Lekgolo, now protectorates of the USR, were in need of supplies of all sorts, from materials to food. The USR provided a little relief by hiring out the Unggoy as manual labor and the Lekgolo as bodyguards and heavy workers. Combined Arms soon began to make deals with the two species, gaining workers for much cheaper prices than what a Human could be hired for.
This gave the company its' second chnce, with a small amount of Human contractors directing Unggoy and Lekgolo miners, both of which were much harder workers than Humans.