FORT LUPTON, Colo. – Addressing workers on a vast oil production field here, Mitt Romney assailed President Obama’s energy policies as “out of date” and pledged to free up more domestic land for exploration.

(Carlos Osorio/AP)

Making his first visit to Colorado since becoming the presumptive Republican nominee, Romney told supporters in this critical general election battleground that he would lower energy costs and create more jobs in oil, gas and coal production.

“This is a choice for the American people: They can decide to stick with President Obama, and many feel he’s a nice guy. I don’t have a problem with the man personally,” Romney said. “But his policies are rooted in perspectives of the past. His ideas about energy are simply out of date. His other policies flow from the thinking of the liberals from years ago.”

Romney believes rising gas prices and the Obama administration’s energy record give him an opening to exploit with independent voters, particularly in energy-rich swing states like Colorado, Virginia and Pennsylvania. Since seizing the nomination, Romney has made regular campaign appearances at energy firms to drive his message.

Here in Fort Lupton, on Denver’s outer suburban ring, Romney spoke in front of a giant black pump with an estimated one billion barrels of oil underground. He acknowledged that the energy sector is actually growing under Obama’s watch, but the former Massachusetts governor argued that this is in spite of the president’s policies, not because of them.

“The president tries to take credit for the fact that oil production is up,” Romney said. “I’d like to take credit for the fact that when I was governor, the Red Sox won the World Series. But neither one of those would be the case. It was not the president’s policies that led to oil production being up. This is private land and private leases.”

The Obama campaign responded by saying that Obama has pursued an “all-of-the-above energy strategy” that is expanding clean coal development and the production of domestic oil, renewable energy and natural gas.

“The real question is why Mitt Romney has embraced a backward-looking strategy of pushing to give more tax breaks to the big oil and gas companies and eliminate protections against Wall Street speculators manipulating oil prices,” Obama campaign spokeswoman Lis Smith said in a statement. “These policies may help the big oil donors that Mitt Romney has cultivated, but they will do nothing to relieve middle class families’ pain at the pump.”

From here, Romney flies to Oklahoma City, where he will hold an evening fundraiser at the home of billionaire oil executive Harold Hamm, a top energy adviser to Romney’s campaign.