Silhouetted against the Sahara, a young Chinese man smiles at the camera while his two companions trudge wearily forward. The snapshot looks like it belongs in a family album. But instead it sits in a brochure for one of China’s fast-growing mining exploration companies. The next photo shows two beaming men in short-sleeved shirts holding gold bars, captioned “First Pot of Gold”.

Relatively unnoticed thus far, dozens of small state-owned exploration companies or “geological bureaus” – with technocratic names such as Jiangsu Geological & Engineering – are expanding overseas in the latest phase of China’s broad push to secure resources.

The big Chinese metals groups have been busily snapping up international mining assets over the past decade to stoke an economy that is now the world’s second-largest.