Workers represented by the Construction, Forestry, Mining and Energy Union (CFMEU) at BHP spin off South32's Dendrobium coal mine in the Illawarra, Australia will go on a seven day strike from Friday.
The workers have announced to go on strike after failure of the workers' negotiations regarding a new enterprise agreement.
CFMEU Mining and Energy Division South West District vice-president Bob Timbs said that the union had been in talks for the past 18 months to reach a new enterprise agreement.
"We sat down with the company again today and put forward some proposals designed to break the deadlock and we are very disappointed with their refusal to come to fair terms."
The union said that the company rejected their request for inclusion of Security of Employment clause in a new workplace agreement.
According to CFMEU, the clause would protect permanent employment and provide future job opportunities for mine workers who are working on a contract basis.
Timbs said that contractor workers will not replace permanent full time jobs and they were supposed to be used to fill temporary gaps in the labour force.
"The company appears to be entering into a strategy of replacing permanent full time employees with contractors when workers retire, resign or are promoted, meaning the permanent workforce is slowly but surely being casualised," Timbs added.
"BHP and now South32 are multinational companies that have extracted billions of dollars out of the Illawarra and they're using every trick in the book to dodge their obligation to workers."
Around 20% of the workers employed at the Dendrobium coal mine are currently contractors.
Under the Security of Employment clause, the company is required to replace a permanent full time employee with another permanent full time employee.
Also permanent employees should be maintained over labour hire in times of redundancy, Timbs said.