Another wedge seems to have been placed between Australia's richest person Gina Rinehart and her prodigal son John Hancock. Mr Hancock was appointed on Tuesday as non-executive director of Volta Mining, a competitor miner of Hancock Prospecting owned by the mining mogul.

YouTube/Volta Mining

Volta operates the Hancock Ranges iron ore project in Pilbara, beside the existing Sirius deposit of Brockman Mining and near a Hancock Prospecting tenement and less than 10 kilometres away from the Hope Downs iron ore project also owned by Ms Rinehart.

Volta Managing Director David Sumich said that the company welcomes Mr Hancock who, he noted, has a lifetime of exposure to the iron ore mining industry in Australia and has skills in financial markets. Before he had a falling out with his billionaire mum, John used to work for the family company.

Mr Sumich said, "John's appointment will provide strong leadership and direction to Volta Mining in the iron ore space, as well as an access to a wide investor base both in Australia and Asia."

Mr Hancock stressed the importance of exploration firms and the junior sector to the future of Australia's resource industry, quoting his grandfather that "Minerals are not like crops of wheat or wool that grow every year. You have got to find more each year if Australia's living standards are to continue."

His return to the mining industry came at a time that investors are unloading stocks as price of iron ore dropped by 8.3 per cent.

YouTube/TheStreet

As a result, shares in Rio Tinto (ASX: RIO) declined 5.8 per cent to $61.20, while BHP Billiton (BHP) share prices went down 4.1 per cent to $36.16 and Fortescue Metal Group (FMG) suffered a 9.4 per cent plunge in share prices to hit a five-month low of $4.92.

The price decrease to $104.70 per tonne on Monday, 22 per cent down compared to a year ago, was preceded by weaker-than-expected trade data from China on Saturday as concerns mounted over the Chinese