Definition: an underground system of holes and passages where people dig out coal or other minerals Level: B2
他们在山里发现了一个丰富的金矿。
They discovered a rich gold ___mine in the mountains.
我祖父过去常在矿井下工作。
My grandfather used to work down the ___mines.
那是一个多少有点工业化的地区，有许多煤矿。
It is a more or less industrial region with many co[al] ___mines.
