(Adds details on capacity addition, BHP plans)
By Rod Nickel
WINNIPEG, Manitoba, May 28 (Reuters) - Canada's Nutrien Ltd , the world's biggest producer of potash fertilizer, said on Tuesday that it was evaluating whether to expand its annual production capacity by 5 million tonnes after 2023, around the time that metals miner BHP Billiton is considering a move into potash.
In a presentation to investors in Toronto, Chief Executive Chuck Magro said the additional capacity would consist of expansions to existing Canadian mines during the next decade.
Nutrien currently has some 5 million tonnes of idled potash capacity due to soft prices in recent years.
Its existing mines could put that idled capacity back into service by 2023, taking its operational capability to 18 million tonnes, Nutrien said in a presentation posted online. It could then begin adding a further 5 million tonnes after that, according to the presentation.
A spike in potash prices a decade ago kicked off a global expansion in production of the crop nutrient, particularly by Nutrien's predecessor company Potash Corp. Excessive capacity resulted in weakened prices and has led several producers to slow output.
Even so, global demand for potash, a key nutrient for corn and sugarcane crops, has risen steadily in Brazil and Asia.
BHP has already sunk shafts for its first potash mine at Jansen, Saskatchewan, but its board has not yet committed the bulk of the capital.
BMO analyst Joel Jackson said in a note this month that he expects BHP to decide in mid-2020 whether to finish the mine, which requires four to five years of construction before it could produce potash. (Reporting by Rod Nickel in Winnipeg, Manitoba Editing by Chizu Nomiyama and Susan Thomas)