The 24-month contract is due to start on July 1, with completion expected in June 2021.
Development works will include 8,796m of decline, incline and level development.
Pybar will be responsible for providing the workforce, equipment and consumables necessary to complete the scope of the project.
An initial workforce of 42 will be employed at the start of the contract and will grow to more than 60 after three months and stay at that level for the rest of the contract.
The existing Hamlet-Athena complex comprises the completed Athena underground mine and the currently operating Hamlet mine.
Hamlet North will be developed from the Hamlet decline over a four-year period to 2022.
Hamlet underground will operate concurrently this year.
Pybar CEO Brendan Rouse said the contract leveraged the company's core strength in rapid development and the operation would scale up very quickly over the coming months in terms of manpower and machinery.
"As part of our recruitment programme we will look to include a mix of local residents and fly-in, fly-out workers," he said.
"In addition to the employment opportunities that will be available we are also committed to the use of local services."