TORONTO/NEW YORK (Reuters) - Anglo-Australian mining giant BHP Billiton Ltd (>> BHP Billiton Limited) is considering selling a 25 percent interest in its Canadian potash mine project, a stake that could be worth close to $2 billion (1.55 billion pounds), people familiar with the matter told Reuters.

The move comes as activist investor Elliott Management Corp has been pushing the company for changes. BHP is working with an investment bank for the potential stake sale in its partly built Jansen, Saskatchewan potash project, the sources said this week.

For BHP, the move will help share the risk of developing the mine and reduce its exposure to the project, said the sources, who asked not to be identified because the deliberations are confidential.

BHP laid out options for the Jansen project in an investor presentation dated Aug. 22, saying it could wait, find a partner, divest or optimise it. BHP spokeswoman Bronwyn Wilkinson said it was too early in the process for the company to have determined the size of a potential stake sale.

"If you bring in a partner, you can share the capital and risk and, depending on who the partner is, help secure an off-take (supply agreement) or offer expertise," Wilkinson said.

BHP, which will keep control of the mine, is not tied to the 25 percent, and the final stake sold could depend on offers, the people said. BHP's 4-million tonne mine would cost about $8.5 billion to build, with more than half of that still uncommitted.

The company does not need the cash either, so it is not in a hurry, the people said. The company's underlying profit surged to $6.7 billion in the recent fiscal year.

BHP's U.S.-listed shares jumped, rising as much as 4.5 percent to hit a two-year high of $43.60. They were up 2.3 percent at $42.68 in afternoon trading in New York.

The potash mine has become the latest front in the battle between BHP, the world's top miner, and Elliott, a hedge fund that has challenged some of the world’s biggest companies.

Elliott's demands include getting BHP to spin off its U.S. oil and gas assets, doing away with its dual-listing structure, and improving shareholder returns. BHP earlier this week said it would exit the U.S. shale oil and gas business.

In July, BHP potash analyst Paul Burnside made a case for potash, arguing that a counter-cyclical investment would help position the company for rising demand for the commodity over the next few decades.

Elliott attacked BHP's plans to enter the potash fertiliser market, which is facing over-supply and sluggish prices. Analysts are cautious about the sector.

Global prices of potash, a crucial crop nutrient that helps corn and other crops withstand stress, are low due to a slump in farm prices and rapid expansion of mining capacity by producers.

The company said this week it would not seek board approval in 2018 as expected for capital to finish building Jansen due to uncertainty in the potash market. Some analysts interpreted the comments as delaying the project. Production could start in the mid-2020s, BHP said.

The potash asset is expected to attract interest from global players, including Indian and Chinese firms, the people said.

Since India relies entirely on imports for potash, Indian fertiliser companies looking to sidestep price volatility could look to take advantage of attractive valuations.

Indian Potash Ltd, IFFCO, Deepak Fertilisers and Petrochemicals Corp (>> Deepak Fertilisers & Petrochemicals Corp), Rashtriya Chemicals and Fertilizers Ltd (>> Rashtriya Chemicals & Fertilizers Ltd), Coromandel International Ltd (>> Coromandel International Ltd) are some of the top potash players in India.

Last month, Reuters reported that Indian agrochemicals producer UPL Ltd (>> UPL Ltd) is exploring a bid of more than $4 billion for the agrochemicals business of Platform Specialty Products Corp (>> Platform Specialty Products Corp), in a sign that Indian agriculture firms were actively scouting for North American assets.

(Reporting by John Tilak in Toronto, Greg Roumeliotis in New York,; Additional reporting by Rod Nickel in Winnipeg; Editing by Bernadette Baum)

By John Tilak and Greg Roumeliotis