WESTERN world tungsten consumers are increasingly concerned about China's grip on the global market, prompting them to seek out direct ownership of non-Chinese mines producing the steel-hardening metal.

The search for non-Chinese supplies has led the consumers to Australian-based Heemskirk, one of a handful of non-Chinese miners of tungsten from its Los Santos project in Spain.

Heemskirk revealed yesterday (Friday) it had received a ''number of corporate approaches'' on Los Santos, the fifth-biggest non-Chinese tungsten mine in the world and the only significant such development in the last 10 years.

Heemskirk would not elaborate but analysts speculated that any number of European tungsten consumers (makers of machine and drilling tools, industrial high-temperature metals, lights and mobile phones) could be looking to acquire a direct stake in the mine to ensure supply.

Los Santos would be worth $50 million to $60 million in a trade deal, although the expectation is that Heemskirk would probably only want to let go of 25 per cent of what is its main operating asset.

A similar-sized tungsten mine, the Panasqueira mine in Portugal, was acquired by the Japanese trading house Sojitz last year for a price believed to have been $US50 million.

Then last year the Swedish mining and construction tool maker Sandvik bought the Mittersill tungsten mine in Austria, also to secure non-Chinese supplies.

China controls about 75 per cent of the world's production of tungsten and, as with the rare earths industry, it strives to ensure the long-term needs of its industrial base are satisfied.

Because of a lack of new mine developments, production of tungsten has been falling by 5 per cent annually since 2004. But demand has been growing at 3 to 6 per cent, China accounting for virtually all the growth.

Heemskirk also owns 40 per cent of the Pajingo goldmine in north Queensland. The group's equity share of Pajingo output is about 25,000 ounces annually. It also owns a business in Canada that supplies drilling muds to the oil industry.

The value of the group's assets is not fully reflected in its share price. At yesterday's close of 52c a share - up 2c - the company's market capitalisation was $57 million.