In the United States, for example, about 800 million tons of coal are mined in the country each year, producing some 120 million tons of ashes and 20 million tons of sulphur compounds when it is burned for electricity generation.
(about 800 million tons of coal; are mined; L:in the country; T:each year; L:In the United States) (it; is burned; for electricity generation)
about 800 million tons of coal it
are mined is burned
L:in the country T:each year L:In the United States
for electricity generation