UN_1957_7TaniguchiS.55earth diggingmaterialsearthethnographicmodernJapan0,42 m3 dry hard clay can be excavated per person per hour0,42 m3 dry hard clay in 1 p-hp-hvar2 / 0,42m3var1 * 0,42Data was converted from work days to person-hours. Author refers to 7 hour work dayIn the UN article is discussed different hardness of the soil. For further types see UN_1957_1-5BuccellatiF.MarkoJ.10.3.2019