The excavation on coal produces two byproducts. The first is mine tailings, scrap rock from the areas around coal seams which is discarded. If these tailings are improperly handled, they can affect the area around the tailing piles, but laws are in place now that require the tailings to be taken care of in an environmentally friendly manner. If it's a strip mine, the law requires that the mine be returned to the state it was in before mining began, and they usually use the tailings to restore the area to pre-mining state.

The second byproduct is the gas PC referred to. Methane has no immediate harmful effect on the areas around the mine, but is a greenhouse gas. The answer to this is to capture the methane and use it to as fuel (natural gas) or use it to produce methanol. This is currently being done in newer coal mines. Why waste a resource by letting it slip into the atmosphere?

Yes, coal is a fossil fuel, and non-renewable, but until alternatives to fossil fuels are researched and turned into commercially viable sources (in the case of wind and solar power) or allowed to be used (in the case of wind and nuclear power) we have to use something to produce energy.

One large problem with one alternative source of energy that has suddenly become the "in" alternative fuel (hydrogen) is that it takes electricity to produce. Where will that electricity come from? Another problem with it is that combustion of hydrogen yields water vapor, which is itself a powerful greenhouse gas.