Brazilian environmental authorities say they have suspended a mining company's operations in Rio de Janeiro state after a retention dike broke, sending sand and clay into an unpolluted river that flows into Rio's Guanabara Bay where Olympic sailing events will be held next year.

Rio state's Environmental Protection Institute says in a statement that Jacunda Mining Co. has been shut down indefinitely and ordered to repair the dike.

The statement issued Tuesday says that "large amounts" of sand and clay spilled into the Roncador River and that tests are being conducted to determine the impact on water quality. Results are expected in 10 days.

The mining company extracts niobium and titanium.