Deep in the waters off the west coast of Australia lies a burial ground of old ships. Known as the Rottnest graveyard, the area holds dozens of historically significant vessels that have been scuttled over the decades, including navy ships and secretive submarines.

Locating the wrecks has proven to be huge challenge, with some of the ships sitting at depths of up to 650 feet — but a small underwater drone has just discovered one sprawling 210-foot shipwreck that dates back about 100 years.

A 15-pound drone named Hydrus used high-tech sensors to capture 4K video and imagery of the shipwreck scattered across the seafloor, according to a news release from underwater exploration company Advanced Navigation, which released video of the discovery.

“Upon returning to the surface, the team analyzed the data and was thrilled to find Hydrus had examined a 64-metre shipwreck,” Peter Baker, subsea product manager at Advanced Navigation, said in a statement.

After establishing the coordinates of the sunken vessel, the team used the drone to perform three missions and complete a full survey of the ship in less than five hours. Experts then were able to create an interactive 3D rendering of the wreckage.

Dr. Ross Anderson, a curator at the WA Museum, examined the images and determined the ship was an iron coal hulk that used to service steamships in Western Australia. The vessel, which was likely scuttled in the 1920s or 1930s, was built as a fast clipper ship used in the grain and wool trade between the U.K. and Australia.

Anderson said the maps and 3D models allow experts to “learn more about untold stories beneath the waves.”

The discovery of the coal ship comes just weeks after officials announced the discovery of the wreck of the coal steamship SS Nemesis off Australia’s coast, more than a century after it sank.

According to Advanced Navigation, there are roughly 3 million shipwrecks still waiting to be discovered off the shores of Western Australia, with only about 1,800 wrecks already recorded.

The company said its team would remain focused on finding other shipwrecks in the area, including the SS Koombana — a luxury passenger ship carrying over 150 passengers before it vanished in a storm in 1912.