screw coal unloader

例句：

1. 1.The new coal unloader has greatly improved the efficiency of the mining operation.
   新型的煤卸载器大大提高了采矿作业的效率。
2. 2.The unloader is designed to handle large amounts of coal quickly and efficiently.
   卸载器设计用来快速且高效地处理大量煤炭。
3. 3.The unloader was used to transport the coal from the mine to the loading dock.
   卸载器被用来将煤炭从矿井运送到装载码头。