Oil and gas companies doing business in Colorado have dropped a mind-blowing $10 million into Amendment 58 — a statewide initiative that would cut their state severance tax and raise roughly $321 million a year for college scholarships, wildlife habitat and other programs. But when it comes to whether big oil may be pumping in cash to help Republicans retake control of the state Senate, well, they're just not saying. And in fact, they don't have to.