Alright, now all creationists have to do is prove that the coal deposits around the world were formed this way, rather than through long-term compression of peat and other plant matter.
By the way, while temperatures above 300 degrees Fahrenheit do occur below the earth's surface, I'm pretty sure that you have to go pretty deep into the crust to get to that point. Not to mention that this is not the only way coal forms. That's why they have to prove that the coal around the world did form that way, rather than just pointing to a way to make synthetic coal and pretending that it proves their beliefs about the flood.
This is the problem with creationist beliefs. They already have what they want to discover in mind, so they only look for validation of what they already believe. Scientists, on the other hand, revise their explanations based on what they actually find. Personally, I find it rather neat that they can make coal this way; my question is whether it's cost-effective to do so.