Macmahon Holdings Limited announced that, it has secured an expansion and three year extension of its work at the Byerwen coking coal mine in Queensland's Bowen Basin. The expansion will involve capital expenditure by Macmahon of $16 million on ancillary equipment. Macmahon has also procured two additional 800 tonne hydraulic excavators for the project worth $37 million, however these machines are subject to a put and call option with Byerwen Coal, and so are not recognised on Macmahon's balance sheet.