1.   It also has plans to close down urban factories and convert coal into electricity near the coal mines to keep the pollution out of the cities.

2.   The companies he founded worked on purifying the air and converting low-grade coal into inexpensive, transportable and high-voltage electrical energy.

3.   Coke ovens are narrow ovens used to convert coal into coke.

4.   He said they sometimes involve converting coal to a gas or mixing it with limestone to produce less pollutants.

5.   The project aims to convert coal directly to oil, without the need for gasification, it said.