North American potash inventories at the producer level, a key indicator of market sentiment, climbed in October, according to the world's top producer PotashCorp, highlighting slumping demand in top offshore markets.

Stockpiles of potassium chloride, the crop nutrient better known as potash, swelled 7.2 per cent to 2.5 million tonnes, according to data posted on PotashCorp's website.

Inventories of the crop nutrient at the producer level now stand 43 per cent above the previous five-year average.

Spot potash prices eased to roughly US$470 per tonne.

Potash supplies have swollen as top global consumers China and India delay signing new supply contracts with Canpotex, the offshore marketing company owned by PotashCorp, Agrium and Mosaic Co.

PotashCorp said last week it would shut two of its Canadian conventional underground mines for eight weeks each between December and February, as per its practice of "matching supply with market demand."

The company said Nov. 14 its mine at Allan, Sask. will not operate between Dec. 16 and Feb. 9, while its mine at Sussex, N.B. will not operate from Dec. 30 to Feb. 23.

The Sussex mine, abut 80 km southwest of Moncton, employed 415 people and yielded about 741,000 tonnes of potash in fiscal 2011.

The Allan mine, about 50 km southeast of Saskatoon, produced 1.02 million tonnes of potash and employed 441 people in the same period. The last such shutdown at Allan ran from Feb. 5 to March 3 this year.

PotashCorp last month also announced eight-week shutdowns in Saskatchewan at its two biggest mines by capacity: Lanigan, idled starting Sunday (Nov. 18) until Jan. 12, and Rocanville, from Dec. 2 to Jan. 26.

The vast majority of the potash produced in North America is mined in Saskatchewan, PotashCorp's home province. -- Reuters, with files from AGCanada.com Network staff

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PotashCorp to idle biggest Sask. mines, again, Oct. 18, 2012