In southwestern Niger, near Niamey, several thousand singleuse bloomery furnaces have been mapped and identified. The archaeological study of approximately 30 furnaces and their slag reveals the existence of four methods for iron smelting: three types of pit furnace and one slag-tapping type. The slag pit furnaces are clearly differentiated by the form and volume of their pits. All slag-tapping furnaces drain off slag through small openings. The slag is tapped either vertically or laterally. According to radiocarbon dates, the smelting activity developed in the 2nd century AD and intensified through to the 14th century. It continued to evolve until the middle of the 20th century. The low intensity of iron production for these furnaces indicates the products were intended mainly for the local market.

中文翻译：

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分类和年表 de bas Fourneaux de réduction du fer à usage unique au sud-ouest du Niger

在尼日尔西南部，尼亚美附近，已经绘制并确定了数千座一次性大炉。对大约 30 座熔炉及其炉渣的考古研究表明存在四种炼铁方法：三种井式炉和一种出渣式。渣坑式炉的明显区别在于其坑的形式和体积。所有出渣炉都通过小孔排出炉渣。炉渣被垂直或横向轻敲。根据放射性碳日期，冶炼活动在公元 2 世纪发展起来，并一直持续到 14 世纪。它一直持续到 20 世纪中叶。这些熔炉的低铁生产强度表明产品主要用于当地市场。