The House Oversight and Government Reform Committee subpoenaed the Environmental Protection Agency on Friday for documents concerning a controversial Alaska mine, the Washington Examiner has learned, in a move that points to increasing scrutiny of the agency's intention to block the project.

At issue is the EPA's signal to veto a key Clean Water Act permit for the Pebble Mine, a proposed copper-and-gold mine in the watershed of southwest Alaska's Bristol Bay. The mine has drawn intense Capitol Hill lobbying, pitting Democrats, native Alaskan tribes, environmentalists and commercial fishermen against Republicans and the industry.

Given the subpoena, the issue is likely to get more congressional attention in the coming weeks and months.

The subpoena from committee Chairman Darrell Issa, R-Calif., which seeks documents dating to 2009, comes a week after he requested the EPA's internal watchdog investigate the agency's decision to veto the permit.

Issa and other senior Republicans on the committee say that vetoing the permit had been the EPA's plan from the project's outset. The EPA says it considered a range of options.

Republicans say the move would be an "unprecedented" preemptive veto because the mine's developer, Pebble LP, has not formally submitted an application to the EPA. They say denying the permit would spook investors near waterways.

The EPA and the mine's opponents, however, said enough public information was available through Securities and Exchange Commission filings to determine the size and scope of the potential mine.

Using such information, the EPA said in January that the Pebble Mine would destroy habitat for Bristol Bay's sockeye salmon, which accounts for nearly half the world's population. It also said the mine would hurt the livelihoods of native tribes.