Digging a Hole to Heaven

Digging a Hole to Heaven — page 1
Millions of years ago during a time called the Car boniferous Period lush forests grew in tropical wetlands Over time the trees and other plant life died and collapsed oventually becoming covered by layers of mud Gradually the buildup of earth pushed the dead plants downward and slowly the plant matter was compressed into coal Humans first burned coal for warmth and for cooling Today coal is used to fire the furnaces that produce electricity and power factories The most economical way to mine coal is on the surface using a technique called open pit mining But in this story coal is mined underground by shaft mining Fossil of Pecopteris a fern from approximately 300 million years