Four abseilers who scaled the Sydney Convention Centre as part of an environmental protest outside BHP Billiton's annual general meeting are expected to be charged.
Police riot squad and rescue officers were called to Darling Harbour on Thursday where about 40 people gathered to protest against the mining giant.
Several groups were involved in the demonstration, including anti-uranium protesters and Aboriginal elders.
Four people abseiled down the building on Thursday to unfurl two banners reading "BHP, Dirty Deeds" and "Australian uranium fuelled Fukushima".
Police at the scene told AAP they expected to charge the abseilers.
A Friends of the Earth spokeswoman told AAP the first pair of activists had been brought down by a police rescue team and taken to Surry Hills police station.
The last two had climbed back onto the roof voluntarily and had not yet been detained, she said.
Arabunna man Kevin Buzzacott was among protesters who gathered at Darling Harbour for the launch of an alternative annual report, Dirty Deeds, which was distributed to shareholders.
The report focuses on the uranium and copper mine at Olympic Dam, South Australia, and the company's proposed liquefied gas hub at James Price Point, in Western Australia.
Mr Buzzacott told AAP he would not be satisfied until the company pulled out of northern SA.
"I don't want them up there destroying the country," he said.
"These bastards are killing us out there in the desert."
Mr Buzzacott believes Olympic Dam operations are causing locals to fall ill, splitting families and damaging sacred sites.
"When you destroy Aboriginal sacred sites you destroy the people," he said.
"A lot of people have gotten sick, a lot of people have died and it is because of them."
The Wilderness Society offered AGM delegates pamphlets warning the proposed James Price Point development would damage a pristine part of the Kimberley coastline, and calling on the company to drop its plans.
Trade unionist Edwin Miejo travelled from Colombia to attend Thursday's protest.
Through a translator, he told AAP he hoped to draw Australian attention to poor working conditions of BHP workers abroad.
"I want to talk about the misery that BHP has generated, the poverty that this company has created in my people, for the workers and the Guajira people where the mine operates," he said.
"BHP wants to change the course of a river which is the main source of water for the communities around the mine."
Comment is being sought from BHP.
In Adelaide, a small group of anti-nuclear protesters gathered outside the BHP Billiton office in Grenfell Street with a large banner calling for the Olympic Dam mine to be closed.
Friends of the Earth spokeswoman Nectaria Calan said the group was concerned by the company's plans to develop a more cost-effective mining process that it did not have approval for.
"It's always a concern when large multinational corporations announce they are looking to cut costs," Ms Calan said.
"In this case BHP are also seeking to bypass the environmental assessment and approval process."