Abstract: Apparatus for the in-situ retorting of carbonaceous deposits includes a plurality of retorts connected to a common exhaust tunnel effectively free of broken shale into which products of the retorting are discharged. To allow simultaneous mining, rubblization and retorting of the in-situ retorts, the exhaust tunnel is provided with doorways between the retorts. Doors movable in the exhaust tunnel are adapted to seal against the doorways to prevent flow from retorts in which retorting is in progress to retorts under construction. A trench in the exhaust tunnel is provided for flow of liquid products produced in the retorting. A liquid seal under the doorways communicates with the trench to provide a passage for liquid flow past the doorways and to prevent upstream flow of gaseous products through the passage for the liquid flow.