MANILA, March 28 (Reuters) - Australia-based Indophil Resources said this week it is looking to list its shares on the Philippine Stock Exchange to win more local support for the long-delayed $5.9 billion Tampakan copper and gold mining project.

Indophil IRN.AX owns 37.5 percent of Sagittarius Mines Inc, the operator for the Tampakan project in the southern Philippines province of South Cotabato, where a 2010 ban on open-pit mining has delayed development of the mine.

Tampakan is believed to be one of the biggest undeveloped copper and gold mines in Southeast Asia, and Sagittarius has already spent about $500 million on initial development.

A dual listing for Indophil, already listed in Australia, may widen its Philippine investor base from about 30 percent currently. Its plan to list "by introduction" in the Philippines would not involve an initial public offering.

Mining giant Glencore Xstrata Plc GLEN.L holds a 62.5 percent interest in Sagittarius, but in January this year it advised Indophil of its plan to sell its stake. Indophil said no formal divestment process has begun so far. ID:nL3N0L42N3

The project faces an uncertain future as long as its ownership remains in limbo, Indophil said.

"Resolving the current ownership uncertainty and having a committed owner and project manager is the next crucial hurdle," Indophil said in its annual report posted on its website on Thursday. "When this matter is resolved, we can offer greater clarity of purpose to all stakeholders."

Glencore had earlier made it clear it has little appetite for spending billions on building new mines, and previously flagged it was reviewing the Tampakan holding along with a range of other big-ticket projects.

Exiting Tampakan would help Glencore meet a requirement to sell down copper stakes, a condition imposed by China before approving Glencore's takeover of Xstrata last year. Beijing had feared the commodities firm would gain too much power in copper.

Discovered in 1992, the Tampakan mine is estimated to have a 17-year lifespan with average planned annual production of 375,000 tonnes of copper and 360,000 ounces of gold.

The mine was supposed to start operations by 2016, a target that has been moved to 2019.

Indophil is partly owned by the Philippines' most diversified conglomerate San Miguel Corp SMC.PS and the country's biggest miner Philex Mining Corp PX.PS .

(Reporting by Erik dela Cruz; Editing by Tom Hogue)

((enrico.delacruz@thomsonreuters.com)(+632 841-8934)(Reuters Messaging: enrico.delacruz.thomsonreuters.com@reuters.net))

Keywords: PHILIPPINES MINING/TAMPAKAN