Judging from the amount of coal found in the world, the earth before the Flood supported about eight to ten times more plants and trees than today. The Flood uprooted the vegetation and formed vast floating log mats similar to those found on Spirit Lake, north of Mount St. Helens, Washington state, USA, after the 1980 volcanic eruption. But the Flood log mats would have been much thicker and much more extensive.
Dinosaur tracks have been found on top of coal seams. This schematic and explanation show the how and why.
The log mats and associated plant debris would settle on the tops of BEDS (Briefly Exposed Diluvial Sediments), during a local to regional fall in the floodwaters (fig. 5a). Dinosaurs that had not yet drowned would swim to this island of brief safety, leaving tracks on the dense plant material (fig. 5b). A subsequent rise of sediment laden floodwaters would then bury the footprints with the plant material before it could float away. Cyclical rising and falling of water levels during the Flood would have quickly deposited huge amounts of sediment that contained multiple layers of plant debris. The increased temperature and pressure due to the weight of the overlying sediment would have turned the plant debris into coal in months, as has been experimentally demonstrated, resulting in multiple coal seams.
The BEDS geological model, based on the global Flood recorded in the Bible, solves many long-standing geological puzzles and helps us justify our confidence that the Bible is reliable.
An abbreviated version of the article A BEDS Origin for Coal by Michael Oard in Creation Magazine 2023, volume 45, Issue 2