Vertical dov zeb
Lub tuam txhab cov cuab yeej siv ntau lawm yog siv rau hauv dov mills, cov cuab yeej tuaj yeem tsim cov kab, hlau, hlau, sawb hlau, tso tawm los ntawm 10,000 tons / xyoo txog 500,000 tons / xyoo:
Sau koj cov lus ntawm no thiab xa tuaj rau peb
