BEIJING (Caixin Online) — One crack in a wall is all it would take for a dark gray oval that sits across 11 square kilometers of land to create a massive disaster.

Situated just to the west of Baotou, a city in the resource-rich region of Inner Mongolia, the mine dump for Baotou Iron and Steel Group (Baosteel) (CN:600019) is enclosed by a concrete wall that stands 20 meters high. It is one of China’s largest tailings pools, and contains roughly 180 million tons of metal waste powder.

Until recently, few outside the city knew about the mine dump, which was created 60 years ago. The mine has gained attention on reports that the hazardous slurry contains large amounts of rare earths and other minerals, estimated by some to have a total value as high as 80 trillion yuan ($12.8 trillion) (US:USDCNY).

But the dump has attracted its share of negative news as well. At least 4,000 hectares of farmland have already been contaminated by seepage. Over 130 hectares of farmland are unable to support crops or have extremely low output.