The shale used for this run was part of a shipment received from the Rifle Station in February 1953. It was obtained form the upper 29 feet of the Mahogany ledge and was crushed to minus 1/4 inch particle size before shipment. It was prepared for the run by additional grinding consisting of one pass through a hammer mill containing a screen having 5/32 openings. The Fischer assay oil content of the shale as charged was 23.4 gal./ton.