In Gafsa, a phosphate mining region in the southwest of Tunisia, a state-controlled company called CPG extracts phosphate from the hills.

Mining, an important economic resource to the Tunisian economy, has been practiced since Roman times. The phosphate mining now accounts for nearly 4 percent of the GDP.

The local mining villages of Redayef, Mettlaoui, Oumm Laarayes, are rich in resources but marginalized by the government. They remain poor, and polluted, a conduit for wealth. Meanwhile, coastal towns prosper.

During the French occupation workers lured from Libya, Morocco, Algeria and around...