Gold-mining firm Dalradian and the PSNI are both seeking legal advice over a bill worth close to £400,000.
That's after the Police invoiced the Canadian gold company for the protection of explosives at its mine near Greencastle, County Tyrone.
Northern Ireland has the seventh richest undeveloped seam of gold in the world, Dalradian has said.
It also hopes to submit an application for full planning permission to develop the mine and a cyanide processing plant before the end of the year. The company says it has already injected more than £56 million into the project.
Responding to a question tabled by local MLA Ross Hussey at the Policing Board on the issue of police protection of explosives to be used at the site, Chief Constable George Hamilton said:
"To date, a total of £397,000 has been invoiced, however Dalradian are in disagreement with the Chief Constable's position on cost recovery."
"Both parties are seeking further legal advice and this matter is with PSNI's Legal Counsel," he continued.
"No monies have been received to date," he added.
The Canadian firm have since responded.
A spokesperson for Dalradian Gold said: “There is a legal requirement in Northern Ireland for the PSNI to assess the need to escort the transportation of explosives.
"The form and manner of the escort is determined solely by the PSNI.
"We understand no other mining or quarrying operation in Northern Ireland pays for this service.
“Dalradian to date has invested more than £56 million in the project at Curraghinalt. Total investment into the project over the lifetime of the mine is expected to be in excess of hundreds of millions of pounds, creating hundreds of jobs in the process.
"This is an opportunity to create a new industry in a region that has not witnessed an opportunity on this scale for a very long time.”
Environmental protesters have objected to Dalradian's plans in County Tyrone - as have some local residents.
The Gortin Rouskey Greencastle Residents Group (GRG) say the plans "will never marry" with the local landscape.
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