A COMPANY behind a £1.5bn mine says tests prove its fertiliser improves farming.
Sirius Minerals wants to extract millions of tonnes of polyhalite from under the North York Moors National Park, near Whitby.
The company says studies by Durham University, the University of Florida and China's Shandong Agricultural University on oilseed rape, potatoes and corn, show polyhalite improves commercial farming yields.
Bosses say the mining project, known as the York Potash Project, could create about 1,000 jobs.
The firm already has agreements to send millions of tonnes of polyhalite to companies in China, Latin America, the US and Africa.
Chris Fraser, Sirius' managing director and chief executive, said: “Our on-going global crop study programme continues to demonstrate the beneficial impact of polyhalite.
“With sales commitments for millions of tonnes already in place across four continents, it's clear there's an extremely large and growing market for this important mineral.”
Sirius hopes to submit the mine plans in July.