CBH Resources, which is owned by Japan's Toho Zinc, has knocked back claims the Broken Hill Rasp Mine could be changing hands.

Chief operating officer Visko Sulicich says Toho Zinc sought a valuation of the mine about six months ago to determine how much it was worth amid skyrocketing commodity prices.

"I think Toho wanted to gauge the potential value of Rasp and, if there were any exceptional or ridiculous offers out there, they would take advantage of it," he said.

The underground operation extracts silver, lead and zinc ore and was officially opened by CBH Resources in 2012.

A NewsCorp report published last week suggested Toho Zinc intended to sell the mine for approximately $300 million and had engaged a corporate advisory firm in Sydney to facilitate the sale.

Mr Sulicich said the company was consulted but there had been no offers for the mine.

"We ran a pretty close process," he said.

"The numbers [in the article] were nowhere near accurate.

Valuations common

Independent corporate analyst Peter Strachan says it is standard practice for businesses in the industry to seek regular assessments.

"Most sensible companies would always be looking at their assets and running the ruler over them to say, 'How much are we going to be able to mine here, given the reserves and resources that we've outlined?'" he said.

"The valuation is basically dependent on how much cash the asset can spit out after paying tax and interest on debt after ongoing capital costs."

Mr Strachan believes Toho Zinc's request may have been influenced by other mine sales in New South Wales.

"They might have had a sniff with someone in the marketplace — there has been a bit of corporate activity in that part of the world," he said.

More than 200 people are directly employed at the Rasp Mine.