9781422285534

27 Chapter Two: Mining Coal

TEXT-DEPENDENT QUESTIONS 1. What is overburden, and how is it removed? 2. How long are longwall coal faces? 3. What is retreat mining?

RESEARCH PROJECTS 1. Find out more about machines that cut coal in longwall mines. How fast do they travel, and how often do they stop for service and maintenance? 2. Look up information on the biggest coal mines that have produced the most coal over the years. Are they in North America?