Satan's World: Polesotechnic League, Book 4
There were three of them - Adzel who measured four and a half metres and resembled a dragon, Chee Lan who was furry, catlike and female, and David Falkayn, a dare-devil rakehell from space.
When they learned of a rogue planet two hundred and four light-years from Sol, they were interested because the planet, a nightmare of ice and darkness, was rich in minerals. And the planet was about to melt - to move closer to a sun and release the vast wealth entombed in its depths.
And Falkayn, Chee Lan and Adzel were prepared to risk the horrors of an erupting, melting world if they could only salvage the riches that would shortly boil from the planet's core...