Protesters and unions from around the world heavily criticise mining company Rio Tinto on Tuesday over alleged lapses in safety leading to the deaths of 41 people and a string of claimed environmental abuses.

Global trade union IndustriAll, which represents 50 million industrial workers across the world, accused Rio of "very wide breaches of fundamental rights" and said the Anglo-Australian mining company could have done more to prevent the 41 deaths last year.

Kemal Özkan, assistant general secretary of IndustriAll, said the deaths of 33 gold miners when a tunnel collapsed at a Rio joint venture mine in Indonesia last May could have been avoided.

He claimed that the Indonesian human rights commission found that the operators of the Grasberg mine, owned with US company Freeport, "had the ability to prevent this from happening but didn't".

"The lack of effort jeopardised the lives of others. The gravity of this case is serious," he quoted Indonesian human rights commissioner Natalius Pigai as saying in a report into the incident.

Jan du Plessis, Rio's chairman, described the Indonesian deaths as a "tragedy" and said the company was doing all it could to improve safety. "We've got to be [by far] one of the leaders in this field [safety]," he said at the company's annual meeting in London.

He admitted that the Grasberg mine, the world's largest gold mine, was "far from perfection". But said Rio's board believed both safety and environmental issues would not be improved by the company pulling out of the operation in Papua.

Well-known private shareholder John Farmer said it was unacceptable for the company to "gloss over 33 deaths just because it [the mine] is managed by someone else".

A company spokesman later said: "Rio Tinto does not manage the Grasberg operation, but we do not stand aside when fatalities occur. We are working with Freeport, the managers of the mine on safety, as well as community, human rights and other issues."

Native Papuan people protesting against the Grasberg mine, which has also been at the centre of alleged environmental abuses, were joined by others complaining about alleged human right and environmental abuses in Madagascar, Australia, Namibia and the US.

Perle Zafinandro, the leader of a community protest group against Rio's majority-owned coastal forest mine in Madagascar, accused the company of "land grabbing and environmental devastation".

Sam Walsh, Rio's chief executive, apologised for poor communication and promised better engagement with local people. He said the level of compensation for people displaced by the QIT Madagascar Minerals mine was negoitated by the Madagscar government, which owns 20% of the mine, not Rio.

Walsh also committed to "turning the area back to what it was" and has employed a "team running a [plant] nursery to be able to fully rehabitualise the area".

Zafiandro said: "How are you going to get these trees to grow on the dead sands left behind?"

Rio has employed horticulturists from Royal Botanic Gardens, Kew to advise it on how to restore the unique and highly endangered littoral [coastal] forest in the southeast of the island.