DENVER - Conservationists say a judge's ruling has given the U.S. Bureau of Land Management a chance to cancel oil and gas leases on parts of the Roan Plateau that are especially environmentally sensitive. The oil and gas industry, meanwhile, contends the judge's ruling doesn't require a vast overhaul. It's the latest back and forth between the two sides as the BLM re-examines its plans for energy development on the biologically rich plateau, which also holds the potential for more energy development that could boost jobs and tax revenues for western Colorado communities.U.S. District Judge Marcia Krieger ruled last year that the BLM didn't fully consider impacts on air quality, potential ozone impacts, and a proposal that would've left much of the plateau's top undisturbed when it approved a drilling plan. However she let existing oil and gas leases on the soaring plateau remain, saying it's possible the BLM could stick with its previous drilling plan even after it takes a second look.The agency is planning to write a new supplemental environmental impact statement on drilling, but first, it gave the public until Saturday to offer comments. "Now, BLM has a second chance to give this crown jewel of Colorado's landscape the protection it deserves," conservation groups said Friday in a letter to the BLM. David Ludlam, executive director of the West Slope Colorado Oil & Gas Association, countered that Krieger's ruling only requires the agency to better explain its decision-making and potentially do more air quality analysis. "In point of fact, more delay and new reams of analysis will not change certain basic realities: Western Colorado needs jobs and energy production from the Roan," he wrote in his own letter Friday.