No one knows for sure when humans started burning coal. Historians have documentary evidence of coal burning in China at least as far back as 1,000 BC, and we know that coal was used for funeral pyres around the same time in Wales. A fairly recent study by John Dodson of the Australian Nuclear Science and Technology Organization used radiocarbon dating of sediment samples in northern and western China to estimate that coal was being used there as early as 2,000 BC. Read the full article.