Abstract: A temporary support structure for use in soft and environmentally sensitive areas to construct roads and pads to support heavy equipment and the like on rough and normally impassable terrain. Roads and pads are constructed by interlocking a plurality of mats together to build a road or pad of the desired size. Each mat is comprised of two layers of boards made of a material with a shear stress equal to or greater than that of hardwood lumber. The top layer of boards are superimposed over the bottom layer and fastened by bolts, nails, glue, etc. Forklifts, cranes, etc., are used to handle individual mats and to position the mats and lock them together.

Abstract: A fuel burning heater has a lower combustion chamber with a door at the front thereof and an upper heating chamber with a discharge port for products of combustion at the rear thereof. A common wall between the heating chamber and a portion of the combustion chamber defines a bottom for the heating chamber and at least a portion of a top for the combustion chamber. A discharge passageway through the common wall conveys products of combustion into the heating chamber with means directing at least a portion of the products of combustion toward the front of the heating chamber. Draft regulators in the lower portion of the door introduce controlled amounts of combustion air for fast burning and other draft regulators in the upper portion of the door introduce controlled amounts of combustion air for slow burning.