Abstract: A method of mining substantially horizontal beds of trona ore, such as are found in the vicinity of the town of Green River, Wyoming, in which substantially all the ore within a given area is extracted. Mining is accomplished by driving substantially parallel entries into the trona formation approximately 100 to 200 feet apart, connecting the entries by at least one primary passage which thereby defines a trona panel, supporting the roof of the primary passage by movable roof supporting structures, and mining the exposed short face or wall of the trona panel. The mined material is removed and the roof supporting structures are advanced so that the structures remain essentially adjacent and parallel to the panel face being mined as it recedes. The roof supporting structures are continuously advanced incrementally to effect caving of the previously supported roof and facilitate mining of the exposed short face of the trona panel.