By Rajasik Mukherjee

(Reuters) -Lynas Rare Earths posted a drop in quarterly revenue on Tuesday, hit by production decline at its Kalgoorlie facility in Western Australia and lower underlying prices, sending its shares to a more than three-month low.

Shares of the rare earths miner fell as much as 2.8% to hit A$5.880, their lowest level since April 11.

Lynas' Malaysian operations also went through a maintenance shutdown during the reported period, which the rare earths miner indicated took over a month.

Total rare-earth oxide output for the fourth quarter ended June 30 was at 2,188 REO tons, plunging more than 50% from a year ago.

"The main bearings on one of the kilns failed and required a maintenance shutdown that took over a month," Lynas said, referring to its downstream Malaysian operations.

Sluggish demand from green energy companies and electric automakers, coupled with rising global supply, have severely dented rare earth products' prices.

"Rare-earths markets continue to be impacted by weakened Chinese demand and high-supply chain inventories....don't currently see near-term support on price," Jefferies analysts wrote in a note.

Lynas said market prices remained low despite a slight improvement in Chinese domestic end-product demand.

The average selling price was A$42.3 per kilogram in the quarter, the company said, compared with A$43.5 per kg a year earlier.

Earlier this month, Lynas flagged disruptions to BHP's ability to supply sulphuric acid, a key ingredient in rare-earths processing, to its Kalgoorlie facility, after BHP suspended its Western Australia nickel operations.

Lynas said it had been working on contingencies with the world's largest miner aimed at the continued supply of acid to the Kalgoorlie plant.

The world's largest producer of rare earths outside China posted sales revenue of A$136.6 million ($90.72 million) for the quarter, compared with A$157.5 million a year ago.

($1 = 1.5058 Australian dollars)