It is Evidence, not conclusion. However, if you read the piece you would see that the formation of Coal and it's various details lend much more to the Flood theory than the old earth, Macroevolution theory. It also calls into question the process of aging levels of sediment (artifacts and vegetation passing through "ages"), a fundamental aspect of old earth theory. This evidence meets the Scientific procedure and cannot be off-handily disregarded because a Christian is using it.
Do you believe that all people & races came from Adam & Eve? Do you believe that woman was created from a man's rib? Do you believe that snakes talk? Do you believe that the entire universe was created in 6 days? Do you believe that dinosaurs wallked the Earth during biblical times? Do you believe that people once lived to be several hundred years old?
If so, where is the scientific evidence that proves such things? "The Bible", "miracles", "God's will" and "faith" are not considered scientific evidence