The $190m contract includes conducting underground mining development and production activities for a period of two years, with the option to extend the contract further by one more year.
The latest extension follows the one year diamond drilling deal offered by the company to the Flying Fox mine last month.
Barminco first started working for Western Areas’s Flying Fox and Spotted Quoll in 2005 and 2011, respectively.
The two mines have combined number of staff of around 210 and had produced approximately 650,000t of ore up to 30 June of this year.
Barminco CEO Peter Stokes said: "We have developed a close relationship with Western Areas and have gained an intimate knowledge of their mines over the last decade, so it is very pleasing to be able to build on that with another contract extension.
"While price is obviously a very important factor, our customers do not award these contract extensions unless we are performing up to standard, both in terms of safety and productivity.
"The contract extension is also a great reflection of our employees’ ability to perform tasks both safely and efficiently at on site, and they are looking forward to continuing to make the operations a success."