The three companies have collectively donated more than $A1 million, a substantial chunk of the $31 million raised so far by the Red Cross bushfire appeal.
Melbourne-based BHP Billiton has donated $500,000 and will match employee donations.
Gold miner Newmont will also match any employee donations to the Red Cross up to $200,000, with the company pitching in $10 for every dollar donated by a Newmont employee.
Wesfarmers has donated $500,000, while mineral sands miner Iluka yesterday offered $50,000.
To find out more about donating to the Red Cross, click here.