The Gravity Miners are a race of alien creatures from a parallel dimension where gravity is a high commodity.
In the Daemonite tongue, they are known as the Chrszy-RR.
Thousands of years ago the Daemonite encountered the Chrszy-RR. The gravity miners robbed the Daemonite home world of much of its gravity; within nine Earth days they had virtually destroyed that planet. Within ninety earth days they had obliterated almost one-third of the Daemonite Galaxy until they were finally pushed back. They returned recently, with Apollo as their prisoner.