Improving efficiency of coal burning and extraction can increase use of coal, especially if no alternative exists and it is the bottleneck for economic development. But if you develop a more efficient technology that doesn’t burn coal, it’s not going to automatically mean more coal will be used. Natural gas, wind, and solar have all increased in absolute terms in the last two decades in the US while coal burning has halved in absolute terms, reducing overall absolute grid emissions in the US.
Anyway, just wanted to point that out. (But I will say Jevons Paradox is a good argument against just relying on improved internal combustion engine efficiency in hybrid cars and buses vs using another energy source for transportation entirely, like renewable and nuclear electricity for trains, electric buses and electric cars.)