Sid Astbury, Sydney – Shares of Arc Exploration tumbled in Sydney trading on Wednesday following violent protests against the gold prospecting operations on Sumbawa island in eastern Indonesian island.

Sydney-based Arc lost 20 percent to 8 Australia cents (8 cents). Financial markets in Australia were closed Monday and Tuesday for the extended weekend Christmas holiday.

Two people were killed and 10 injured when police opened fire on demonstrators on Saturday in Lambu, Sumbawa. Dozens of buildings were set on fire and dozens of arrests were made. Sumber Mineral Nusantara of Indonesia is the local partner in a project in which Arc has a 95 percent stake.

Arc has suspended work on the project in Sumbawa where it has a license to explore 250 square kilometers. Sumbawa is located just east of Bali, a resort island popular among overseas travelers.

"Contrary to some reports, there is no gold mining existing or under construction, nor is any gold mine presently contemplated," Arc said in a statement to the Australian stock exchange. The company said that it was "an exploration company and does not undertake any mining."

Christine Milne, a member of parliament for the Greens, told Melbourne's The Age newspaper that an investigation into the deadly clash should be held.

"What we would like is to have the Department of Foreign Affairs and Trade immediately investigate and report back to the Australian people about what exactly took place and what arrangements Arc Exploration has with the local police," Milne said.

"Australian companies should abide by the same standards of human rights and environmental compliance that they would have to undertake here in Australia," she said.