Western Mine Workers’ Alliance (WMWA) said that BHP Group’s new alcohol policy the bans workers on mine sites from drinking alcohol after 9:30 p.m. impinges on workers’ rights.

In a letter this week, the union told BHP the policies raised concern over employees’ basic rights to privacy and enjoyment in non-working hours, and added that the miner had not adequately consulted employees.

“If there are issues with some staff, they need to be managed, rather than penalizing all the rest of the workers,” Shane Roulstone of the Australian Workers Union told Reuters. “We just want to be treated like adults.”

The mining giant introduced a policy in January to limit workers’ daily consumption to six mid-strength beers, while giving management the power to search personal property, Roulstone said.

Further curbs set to take effect from July 1 bar on-site drinking areas from serving alcohol after 9:30 p.m. and workers from consuming the beverage in their quarters, he added.

That meant that support staff, such as cooks, who finish work after the deadline will be denied a drink after work, Roulstone said.

Workers in mining villages are typically provided with small bar fridges in their rooms that stock at most four beers.

For those who fly in to remote mine sites to work for two weeks at a time, the new rules unfairly limit drinking on nights off during transitions between day and night shifts, he said.