• 2022-05-29
    over of all dust generated during mining
  • 50%

    内容

    • 0

      English ………. all over the world.

    • 1

      During their first winter, over half of the settlers died of or epidemics.

    • 2

      Many practical areas of engineering controls designed to mitigate exposure of surface mine workers to all airborne dusts, including silica, are: A: drill dust collection systems B: enclosed cab filtration systems C: controlling dust on unpaved haulage roads D: controlling dust at the primary hopper dump

    • 3

      The Great Wall _____ all over the world.

    • 4

      The news was _____ to people all over the world.