The contract comes with an option to extend the order to 6 years.
To fulfil the contract Mitchell will initially deploy two underground diamond rigs to Kalgoorlie.
Under the contract NRW will carry-out bulk earthworks and put in drainage infrastructure.
MACA will get started on the contract in February, providing Adaman sorts out project finance.
The locally designed and manufactured machines will work at a rate of 20,000 tonne per hour.