REFILE-FACTBOX-Five facts on Pebble mining project in Alaska

TORONTO, Sept 9 (Reuters) - Alaska's massive Pebble copper-gold deposit is getting closer to the permitting phase, but political and environmental concerns could derail the multibillion dollar project before it even gets underway.

The project, which is near a world-class salmon fishery in the Bristol Bay region, faces opposition from scientists, aboriginals, environmentalists and even Hollywood celebrities.

Here are five facts about the Pebble project:

- Northern Dynasty and Anglo American are joint venture partners in developing the project, which will likely be one of the largest open-pit mines in the world. In a preliminary study released earlier this year, Northern Dynasty outlined 25-year, 45-year and 78-year options for production.

- Permitting will likely take at least three years and construction is expected to take four years. The project will employ around 2,000 people during the construction phase and 1,000 people afterwards.

- The mine will produce gold, copper and molybdenum, a metal used to harden steel. To process the ore, a technique known as flotation will be used. The rock is crushed into a powder and then a detergent-like substance is used to separate the metal from the waste material.

- After the metals are separated, two types of tailings would remain. About 85 percent is benign, but the remainder can become acidic if exposed to oxygen. The company is planning a lined, earthquake-proof facility to deal with the tailings.

- The project is located in a remote area of southwestern Alaska. In addition to the mine and processing facilities, the company will need to build 86 miles of road, a pipeline to pump the metal slurry to a deep-water port in Cook Inlet, sewage and water treatment plants, and the infrastructure to power the project.