 Coal mining takes place in the three mountainous regions at 45 distinct coal beds near Mesozoic basins . Over 62 million tons of other non @-@ fuel resources , such as slate , kyanite , sand , or gravel , were also mined in Virginia in 2012 . The state 's carbonate rock is filled with more than 4 @,@ 000 caves , ten of which are open for tourism . 35 million years ago , a bolide impacted what is now eastern Virginia . The resulting crater may explain sinking and earthquakes in the region . 
