Addressing the company’s Australian annual general meeting in Melbourne this morning, du Plessis noted the challenges in Europe and uncharted territory in the US as quantitative easing wound down.

“Financial markets continued to be volatile in 2013 and while the outlook is now brighter in some parts of the world, we believe that volatility looks set to remain in the short to medium term as a number of structural deficiencies remain unresolved,” he said.

Du Plessis tipped near-term “variability” in the Chinese economy as authorities navigated the company’s growth.

“There is no question, however, that the Chinese leadership remains committed to pursuing economic reform, which offers potential benefits for the global economy in the long term, even if there is some variability along the way,” he said.

He also noted political uncertainties.

“The recent events in the Ukraine, the conflict in Syria and the turmoil in Egypt are but a few examples of tremendous turbulence that underlines the fragility of the contemporary geopolitical environment,” du Plessis said.

CEO Sam Walsh spoke of the company’s growth opportunities, including an underground expansion at the Oyu Tolgoi copper-gold mine in Mongolia, the La Granja copper project in Peru, the Resolution copper project in the US and the South of the Embley bauxite project in Queensland.

“All of these projects are available to be considered for investment when the time is right,” Walsh said.

He admitted the aluminium industry was “doing it tough”

“Different parts of our portfolio have their time in the sun at different times,” he said.

Rio faced a number of shareholder questions with the hot topic being uranium after leach tank failures at both the Rossing mine in Namibia and the Ranger mine in the Northern Territory, which is operated by subsidiary Energy Resources of Australia.

When asked by a representative of workers at Rossing about increased cases of cancer, du Plessis expressed “slight irritation”

“I sometimes question the motives of organisations who come into a public forum and make public statements,” he said.

Du Plessis said the group had given Rio a report into the health of Rossing workers at its London AGM and the company was “looking into it”

Walsh was firmer on the subject, saying the company monitored the health of its workers at Rossing.

“There is no medical evidence of widespread health issues at Rossing,” he said.

“We have committed to an independent review.”

The company also faced a number of questions from concerned Hunter Valley coal workers on safety and jobs, which it promised to follow up.

One shareholder asked about the Simandou iron ore project in Guinea after Rio last week launched US court proceedings over the loss of half of its stake in 2008, accusing Vale and BSG Resources of racketeering.

Du Plessis said he couldn’t speak in detail on the matter.

“We feel quite aggrieved and we intend to pursue this vigorously,” he said.

He stressed that the complaint was not against the Guinean government.

“Our relationship with the government is a good one,” he added.

Shares in Rio were last trading 1.1% higher at $A61.28.