Almost every morning at 6 a.m., 49-year-old Mahfuh Usman sets out for the Sanaga River, some 63 km from his home in Nkozoa, a locality in Yaoundé, Cameroon’s capital.
From the banks of the longest river in Cameroon, he gathers different types of stones, including granite, basalt, shale, agate, clear quartz, and pebbles. After filling several wheelbarrows, he loads them into his car and returns home. There, he sorts them, mixes a bag of cement with water and sand, and then measures it on a square mortar the size of a regular tile.
