Khib yog qhov pib yooj yim hauv kev lag luam kev lag luam hauv tshuab, thiab nws tseem yog qhov tseem ceeb uas tseem ceeb tsis tau. Nws yog dav siv hauv cov khoom lag luam xws li tshuab cuab yeej, tshuab kaw lus, metallurgical machinery, siv tshuab ua liaj ua teb, thiab tsheb thauj khoom thauj.
