Andrew Forrest has spent close to $24 million increasing his majority stake in iron ore miner Fortescue Metals Group.

The Fortescue founder and chairman bought more than 5.2 million Fortescue stocks on the share market between September 17 and 23, for a total price of $23.61 million.

That takes his ownership stake to 33 per cent, which is currently worth more than $590 million.

Meanwhile, Fortescue has taken control of ore processing at its Christmas Creek mine, where a worker died in an accident in a crushing plant last month.

Fortescue says it has exercised its step-in rights to immediately take over the management and supervision of ore processing from contractors Crushing Services International.

The company stepped in to ensure the safe and hazard free operation of the ore processing facilities, Fortescue said.

Crushing Services International’s owner, Mineral Resources, said it was confident the issues would be resolved shortly.

While there has been disruption at Christmas Creek, Fortescue does not expect its full year production target range of 127 million tonnes to 133 million tonnes of ore, to be affected.