saltpetering

例句：

1. 1. The saltpeter mine is the largest in the region.
   盐矿是该地区最大的。
2. 2. The saltpeter mine has been closed due to environmental concerns.
   由于环境问题，盐矿已被关闭。
3. 3.The saltpeter mine was discovered by a local explorer.
   盐矿是由一位当地探险家发现的。