In a recent excavation in Bui Ben village, Yen Lu commune, Yen Dzung district, archaeologists uncovered six kilns, including two near the Cau river's bank that used to produce bricks, tiles and other potteries.

These products are similar to those found in Co Loa ancient citadel in Hanoi and the two northern provinces of Lao Cai and Vinh Phuc.

Archaeologists said the brickyard used to be an iron handicraft workshop in the 13th-14th centuries.
Covering an area of 10,000 sq. m, it includes a large number of cinder piles and metallurgical tools.
These iron products prove they were made by hand at the workshop for sale.