KUANTAN, Malaysia — The world’s largest refinery for rare earth metals has risen out of the red mud of a coastal swamp here and could soon obtain permission to operate — a step that would help break China’s near monopoly on rare earths but also worsen an emerging glut of some of these strategic minerals.

China’s suspension of exports of rare earths to Japan during a territorial dispute in 2010 fed a bubble in the market that drove prices up 30-fold by last summer. But prices have slumped by up to three-fifths since then for some of the 17 rare earth elements, which are vital to smartphones, wind turbines and other components of the modern economy. The approaching completion of the Malaysian refinery, with the capacity to meet a fifth of the world’s demand, has contributed to the plunge.

The progress toward opening the plant has occurred despite street demonstrations here over radiation worries, regulatory challenges and the withdrawal of a major equipment supplier worried about the safety of the refinery, which is being built by Lynas, an Australian company.

Raja Dato Abdul Aziz bin Raja Adnan, the director general of the Malaysian Atomic Energy Licensing Board, said by telephone Monday evening that the board had discussed at a closed-door meeting earlier in the day whether to grant an initial operating license of up to two years for the refinery, which is a series of more than a dozen sprawling buildings connected by a labyrinth of pipes. He declined to say what the board had decided, but added that an announcement would be made “sooner rather than later.”