Urosek, of the U.S. Mine Safety and Health Administration (MSHA), proposed creating a pressurized air pocket for the miners. Urosek's plan had never been tested in the United States, but despite some skepticism, calculations were made, and the hole was sealed around the air supply. The drill operator then used his rig's air compressor to pump and maintain 920 cubic feet per minute at a temperature of at . The sound due to the high rate of pumped air deafened and hurt the miner's ears, but provided hope by the knowledge that rescuers knew where they were. Drilling and efforts to slow flooding Meanwhile, an ongoing battle was to dewater the Quecreek Mine to allow rescue operations to be planned. Millions of gallons of water had to be pumped from the flooded coal mines as the water level needed to be lowered to prevent the loss of the air pocket in the mine area where the nine miners would congregate. Should a rescue hole penetrate the mine, the air pocket could escape and the air filled void area become flooded, and the miners would drown. The second grave concern was the quality of the air in the mine. Pumps were set up as they became available. Work proceeded immediately to install pumps in the pit as they arrived. At 8:33a.m. Thursday, the first of several diesel pumps arrived at the mine site. Before this pump arrived, only two submersible pumps were operating in the sump area of the pit. At 11:05a.m., water was four to five feet deep in the mine pit entrance. Water in the pit reached a maximum elevation of at approximately 4:00p.m., Thursday, July 25. High-capacity diesel pumps were installed in the pit and put into operation in the afternoon. A drop in the water level was reported between 4:00 and 6:00p.m. The pumping discharge rate fluctuated constantly as new pumps arrived and changes were made. The maximum pumping rate achieved was approximately 27,000 gpm at the mine pit. Additional borehole locations were surveyed on the surface for holes to be drilled into the lowest area in the mine. Additional dewater holes were drilled to accelerate dewatering. Back underground, rising water covered the air shaft, preventing the miners from tapping on the pipe, though for a time they used a hammer to bang on the rock ceiling, detectable by seismic equipment which was brought in by Federal