waste reutilization

Identify two processes by which coal byproducts are or can be reutilized (waste reutilization). Explain the benefits of these processes provided by society and any potential ramifications that may accompany them.
Please address the following:
Describe at least two processes by which coal byproducts are or can be reutilized.
How does society benefit from these processes?
What potential ramifications exist with each of these processes?
How might waste reutilization affect the economic viability of coal as a source of energy?