Downhole separator system and method

According to one embodiment of the invention, a downhole separation method includes forming a main wellbore extending from a surface to a subterranean zone, disposing a production liner into the main wellbore proximate the subterranean zone, coupling a first end of a first tube to the production liner, coupling an entrance portion of a second tube to an outside surface of and adjacent a second end of the first tube such that an entrance of the second tube is at a lower elevation than the second end of the first tube, and causing a flow of a mixture through the production liner and the first tube. The mixture includes a gas, a liquid, and a plurality of coal fines. The method further includes retrieving the gas via the main wellbore after the mixture exits the second end of the first tube and retrieving at least the liquid through the second tube.