What is Benton Hawkes belief is the reason he is being sent to Mars in the novel, Man O’ War?

Benton Hawkes is ready to retire when he receives his assignment and would prefer nothing more than to stay on his Montana ranch with his horses. Mining interests, however, are trying to dig his land right out from under him, and Benton suspects that his assignment to Mars (devised by his many enemies) is a ploy to get him out of the way.