A total of 19 trains carrying coal to Australia’s flagship export hub for the fuel were disrupted after a protester suspended themselves from two poles over rail tracks.

Part of a rail line in Kooragang, close to the Port of Newcastle in New South Wales state, was halted for more than four hours from 7 a.m. local time Monday, according to the Australian Rail Track Corp., which manages the network.

A 22-year-old woman was arrested at the scene after law enforcement removed the structure from the tracks, New South Wales police said in a statement.

Australia’s status as the world’s No. 2 coal exporter has long been a focus for activists who argue the nation’s sales of the fossil fuel are a key contributor to global emissions. While Prime Minister Anthony Albanese has legislated more ambitious national climate targets, his government has also shown support for a coal sector forecast to generate about A$128 billion ($88 billion) in export earnings this fiscal year.

Blockade Australia’s demonstration at Kooragang was “a response to Australia’s destruction of the climate,” the campaign group said in a message posted to Twitter. Two separate protests also took place Monday near the Port of Melbourne and Port of Brisbane, the organization said.

Newcastle Coal Infrastructure Group, which handles coal exports for producers including BHP Group Ltd., Yancoal Australia Ltd. and Whitehaven Coal Ltd., didn’t immediately respond to a request for comment.

BHP declined as much as 1.1% in Sydney by 1:08 p.m., as Whitehaven fell as much as 3.9% and Yancoal by as much as 2.8%.