MELBOURNE – BHP expects to present its board with a decision in a few months on whether to go ahead with its Jansen potash project in Canada after choosing between two port options, a company executive said on Thursday.

The world's biggest miner has estimated the project in Saskatchewan province would cost up to $5.7-billion in its first phase. The project offers BHP diversification into agricultural markets given that potash is a key element in plant nutrition that also makes crops more drought resistant.

"We are considering two options in terms of the port. One is a commercial option at the port of Vancouver, one is a greenfield option," Ragnar Udd, president of BHP's Minerals America, told investors on Thursday.

"We would like to have those locked in before we take them to the board. We continue to expect that this (decision) will occur in the next, coming few months," he added.

CEO Mike Henry said at its half year results investor call that although BHP has said a decision would be made mid-2021 it was now maybe "a slightly wider range".

The miner expects the potash project will take five years to develop and have an annual production capacity of around 4.4-million tonnes in its first phase. It will have capacity for an additional 12 million tonnes thereafter for a life of 100 years.

Udd was speaking to investors about the outlook for the potash market, for which BHP expects demand to catch up with supply by late this decade or early next.

BHP estimated global production of potash was 76-million tonnes in 2020, which could rise to 86-million tonnes when factoring in latent capacity.

It expects demand to grow by 15-million tonnes to around 105-million tonnes by 2040 or 1.5% to 3% a year, along with the global population and pressure to improve farming yields given limited land supply.

BHP sees operational expenditure at the Jansen potash mine at $100/t and sustaining capital expenditure at $15/t. It sees incentive pricing for new projects at $300/t to $500/t, with Canada the main supplier.