FACTBOX-Mining policies of top Chile presidential candidates

SANTIAGO Dec 7 (Reuters) - Chile's presidential favorite, conservative Sebastian Pinera, has vowed to sell part of world No. 1 copper miner Codelco, if he wins the vote, but union resistance and a split Congress will likely block him.

Pinera and his closest rival, Eduardo Frei, a former president running for the governing coalition, have vowed to push investor-friendly policies that lured billions of dollars in mining investment to the world's top copper producer.

Independent leftist candidate Marco Enriquez-Ominami, who is polling third, has worried investors with plans to raise royalties on miners and hack away at corporate tax breaks.

However, the 36-year-old candidate is seen unlikely to make it to a two-man January run-off, is considered a far cry from Venezuela's firebrand leftist Hugo Chavez, and says he believes in financial markets.

Mining policies of the top three candidates are as follows:

Sebastian Pinera

* Sell up to 20 percent of state-run Codelco to private pension funds in Chile. His advisors have also floated the idea of listing the stake on the bourse.

* Revamp the corporate management of Codelco and other state companies.

* Create incentives for private companies and miners to build desalinization plants to feed mining operations in water-scarce regions like the mineral-rich Atacama desert.

* Offer tax incentives to miners who develop new technology and expand research. He wants to lure more foreign mining investment to help his government achieve a target of 6 percent annual growth for the Chilean economy.

* Foster investment in mining exploration and alternative energy sources.

Eduardo Frei

* Boost Codelco's investment budget and keep the company fully in state hands.

* Increase financing options for local small- to mid-size miners.

* Review water concession law pitting farming communities against mining companies in the water-starved Atacama desert.

* Willing to study nuclear power as a source of energy for an industry struggling with rising energy costs.

Marco Enriquez-Ominami

* Initially offered to sell up to 5 percent of Codelco, but later said a new law that overhauls the state giant's governance could be enough to improve company efficiency.

* Raise royalty on miners to 8 percent from 5 percent to bring in an extra $400 million a year.

* Tax hydroelectric plants to raise an additional $450 million.

* Scrap tax exemptions to collect $1.5 billion a year.

* Force Codelco to either develop or sell mining concessions it holds to boost exploration.

** Policies gathered from candidates' comments, government plans and mining advisors.

For main story, please double click on [ID:nN07158519] (Reporting by Alonso Soto; Editing by Simon Gardner and Walter Bagley)