Kev lag luam kho vajtse hais txog kev kho vajtse, kev tsim khoom, kev tsim khoom, smelting, mining thiab lwm yam dej num ntawm kev lag luam. Tom qab xyoo ntawm txoj kev loj hlob, kev lag luam kho vajtse tau nkag mus rau lub sijhawm "polarisation", thiab "txoj cai ntawm ob lossis yim" tau dhau los ua qhov tsis tseem ceeb ...
Nyeem ntxiv