Chongqing - The Chongqing Cultural Relics and Archaeology Research Institute excavated the Small Farm Iron Smelting Site in collaboration with Sichuan University from July to November 2023.

Covering almost 1,000 square meters, the site unveiled extensive remnants of iron smelting from the Song and Ming Dynasties, featuring furnaces, iron ore processing areas, and slag accumulation zones.

Panoramic view of the Small Farm Iron Smelting Site in Wulong District (Photo/Chongqing Daily)

Compared to contemporaneous sites in Chongqing and the southwest, the Small Farm site stands out as the region's earliest, largest, and most well-preserved iron smelting site during that era, with an impressive operational history.

Remarkably, the stone components excavated in the site at the furnace's tuyere represent China's first direct evidence of protective measures for the tuyere nozzle during the smelting process.

Tuyere was discovered at the Small Farm Iron Smelting Site (Photo/Chongqing Daily)

The meticulous excavation of the site has revealed a comprehensive journey of pig iron production. This journey covers the entire metallurgical process, ranging from raw material processing to pig iron smelting and slag disposal. It offers a detailed perspective, from material processing to the final stages of pig iron smelting and waste management.

Slag accumulations of deposits found at the Small Farm Iron Smelting Site (Photo/Chongqing Daily)

According to Wang Hongling, curator at the Chongqing Cultural Relics and Archaeology Research Institute and lead of the Small Farm site project within the Chongqing Wujiang Baima Navigation and Hydropower Project, ancient workers mined iron ore from local open-pit mines or shafts, transporting it to the site's smelting factory for further refinement. 

Blast furnaces were meticulously crafted in the adjacent smelting zone using refractory clay. Loaded with iron ore (hematite and magnetite), charcoal for fuel, and limestone as a flux, these furnaces facilitated a chemical reaction, allowing pig iron to flow from the lower "golden gate." 

Notably, a specially crafted stone protective tube extended the tuyere's durability under high temperatures, marking the first national evidence of protective measures for the tuyere in the smelting process.

Experts are inspecting the Small Farm Iron Smelting Site. (Photo/Chongqing Daily)

The Small Farm site excavation represents just one example among many in the Wujiang River basin. Bai Jiujiang, President of the Chongqing Cultural Relics and Archaeology Research Institute, shared that the institute initiated comprehensive surveys and explorations in the area affected by the Chongqing Wujiang Baima Navigation and Hydropower Project more than a decade ago. 

Their findings reveal a prolonged history of smelting near the Small Farm site, a tradition stretching from the Han through the Song and Ming Dynasties and persisting into modern times. The area's rich raw materials, abundant water sources, and convenient transportation have all contributed to the sustained prevalence of iron smelting activities in this region.

Blast furnace for iron smelting discovered at the Small Farm Iron Smelting Site (Photo/Chongqing Daily)

(Cheng Jialu, as an intern, also contributed to this report.)