How might a Mexican drug cartel diversify its operations?

You may imagine kidnapping, extortion or maybe arms trafficking as potential business lines.

But exporting panamax-size shipments of iron ore?

That is exactly what Mexican authorities say led them to detain the 73,700-dwt Jian Hua (built 2000), which is being held at the port of Manzanillo with nearly 68,800 tonnes of the mineral.

The cargo is suspected of being tied to the iron ore export operation of violent criminal organisation the Knights Templar, whose base of operations is the southwestern state of Michoacan — the home of the massive port of Lazaro Cardenas.