March 27 (Reuters) - The Chilean government's new plan

to usher in private investment at a number of the country's

lithium salt flats may stumble over unresolved details that will

raise concerns for investors, mining executives and analysts

said on Wednesday.

Industry players said they are seeking information on how

contracts will be awarded by officials in the country that is

the world's second-biggest lithium producer and are worried

about pushback from Indigenous communities and environmental

campaigners.

Chile in April will begin seeking proposals from private

firms interested in extracting lithium, a key energy transition

material used in electric vehicle batteries, from 26 salt flats

not earmarked for state control, officials said on Tuesday.

The plan is one of the new planks of President Gabriel

Boric's 2023 lithium policy mandating public-private

partnerships.

The government will reserve two of its best salt flats,

Atacama and Maricunga, for majority control through state-run

copper miner Codelco, while progressing projects via state-run

companies at another five salt flats.

The state-developed projects alone are expected to double

Chile's output to about 500,000 metric tons of lithium carbonate

equivalent by the end of decade, Mining Minister Aurora Williams

said on Wednesday.

For the remaining 26 salt flats, officials will accept

statements of interest through July.

Nearly 100 companies from a dozen countries have already

approached the government to seek information about launching

lithium projects, Williams said, including from the U.S. and

China.

Yet, executives and analysts pointed out red flags in

Tuesday's announcement they say could put a damper on new

projects.

One concern is how the government will award lithium

contracts in salt flats where mining concessions have previously

been granted, which risks creating a kind of double ownership.

"It creates many potential conflicts, setting the stage for

future judicial problems," said Sebastian Yang, a board member

of Simco Lithium, which has a project in the Maricunga salt

flat.

"This will pose a difficulty for attracting potential

investors."

Chile's Mining Ministry did not immediately respond to a

request for comment.

Jose Hofer, a lithium adviser at consultancy SC Insights,

said other challenges that could curb investor appetite include

required state partnerships, potential pushback from Indigenous

communities and limits on extraction throughout a swath of the

salt flats due to environmental protections.

"This over layering of policies and excess of state

involvement has made Chile 'un-investable' in lithium," he said,

noting that Argentina and Brazil will likely become more

significant players compared to Chile over the next decade.

Companies must also grapple with a soft patch for lithium

prices amid a slowdown in EV sales, which has changed the

calculus for ensuring economically viable projects.

For Canada-based Wealth Minerals ( WMLLF ), moving forward

with its lithium project in the Atacama salt flat will mean

starting talks with Codelco over the terms in which the

state-owned miner will take a majority stake, said Executive

Director Marcelo Awad.

"We're optimistic and very interested in starting a

negotiation with Codelco as soon as possible," he said.