OFFICIALS behind a multi-billion pound fertiliser mine have discovered greater reserves of a material they hope will give it a foothold in lucrative chilli pepper and tea markets.

Sirius Minerals says its probable stock of polyhalite now stands at 280 million tonnes.

Bosses say the figure is higher than a previous 250 million tonne estimate and of better quality.

Sirius has planning permission to build the York Potash Project, near Whitby, and aims to create and support thousands of jobs by extracting the multi-nutrient fertiliser.

Production is planned to start in 2021 and the company says fresh tests have strengthened its position.

According to latest assessments, its polyhalite, reputed as a rich provider of crop growth due to its potassium, magnesium, sulphur and calcium nutrients, is capable of bolstering chilli pepper, tea and oilseed rape yields.

JT Starzecki, Sirius’ sales and marketing director, said its product, trademarked as Poly4, has significant potential.

He told The Northern Echo: “These results are the latest to demonstrate Poly4’s ability to increase yield and quality in a range of crops.

“Oilseed rape, chilli peppers and tea are major crops in China, with a value of $33.3bn (£23m) annually, and these trials help us show Poly4 can play a significant role in helping achieve more sustainable and effective fertiliser solutions.

“We look forward to announcing our next results when they become available.”

Earlier this year, Sirius unveiled a definitive feasibility study, which showed it is targeting up to £2bn earnings, before taxes and interest, once the mine is fully operational.

Bosses also confirmed they want to raise £2.4bn to fund the project through two stages, and said interested parties are digesting the figures ahead of putting forward potential backing.

Speaking to The Northern Echo, Chris Fraser, Sirius’ managing director and chief executive, said he was confident of the mine’s long-term success, saying it aims to produce polyhalite at $30 a tonne and sell it for potentially $200 a tonne.

Sirius will see shafts sunk at the former Doves Nest Farm, with its polyhalite due to be transported via conveyor belt to a handling site at Wilton, near Redcar, for granulation, storage and distribution, before being exported from a harbour.

A decision on that harbour, earmarked for the mouth of the River Tees, is expected from the Government in the coming months.

Sirius already has a number of supply agreements for York Potash, including a deal with a US-based firm to annually dispatch 1.5 million tonnes for seven years, which could be extended further across two five-year periods.