NOVELTY - Converting coal ex situ involves: a) treating coal with a liquid that solubilizes at least a portion of the coal; b) treating at least a portion of the product of step (a) with a hydrolytic microbial population to produce a product containing fatty acids; and c) treating at least a liquid portion of the product from step (b) with an anaerobic microbial population that generate methane to produce a product containing methane.    USE - For ex situ conversion of coal selected from lignite, sub-bituminous coal, bituminous coal, semi-anthracite coal, and/or anthracite coal into methane or a product containing methane (claimed); and for producing carbon dioxide, gaseous and liquid hydrocarbons and other valuable products useful as clean fuel for heating, power generation and transportation, from coal.    ADVANTAGE - The process converts coal into hydrogen, methane, carbon dioxide and other valuable products that can be utilized as a clean fuel for heating, power generation and transportation. The process utilizes preprocessing steps including particle size reduction and solubilization pre-treatment to enhance and accelerate bioconversion. A buffer tank is also utilized to equilibrate physical and chemical properties of the volatile fatty acids and acid esters produced, such as pH, temperature, conductivity, nutrients and biochemical oxygen demand, collected from different hydrolysis reactors and provide a method to control the volatile fatty acid and ester loading rate into the biogasification reactor. This equilibration process provides for greater and more consistent gas yields, such as a much greater concentration of methane and reduced concentration of carbon dioxide, because the bacteria in the biogasification reactor are able to more efficiently process a consistent flow of volatile fatty acids and esters into the reactor. The system is designed to maximize and optimize the use of the hydrolysis reactor volume in order to achieve very high conversion efficiency of the coal, in terms of maximum gas production rates at lower capital and operating costs. The process enables hydrogen gas produced in the hydrolysis reactor and the buffer tank to be used in the biogasification reactor, and at a stable, high rate, yielding higher conversion rates to methane. Thus, the present process of bioconversion of coal to much cleaner-burning methane and other useful products increases the supply of these energy resources to effectively utilize a fossil fuel resource that is otherwise be wasted or not used, and to employ technology that has a low environmental impact with high efficiency. Consequently, anaerobic bioconversion of coal has lower capital and operating costs, has higher thermodynamic efficiencies, and produces much less gaseous emissions and solid wastes.