Beater Room and Groundwood Mill

The Ocean Falls paper mill included a department called a "Beater Room". Today a beater room is of old pulp  technology. The "Beaters" of the past are now replaced by refiners and repulpers. The Beaters were large oval wooden tubs with a center wall and a large beater roll mounted on one side of the vat. The beater roll, also made  of wood, was equipped with numerous steel bars mounted in the surface of the roll. The beater tub was then filled with paper stock or recycled paper waste plus water. The paper and pulp would be drawn between the beater roll and the bottom of the tub and would circulate this way many times around the vat. These beaters were an important part of the stock preparation process  to prepare the paper stock for the paper machines. The beaters would operate on a batch principle, the stock being dumped into a beater chest once the paper stock was properly refined. Each batch of beater pulp had to be tested before being dumped to ensure the proper separation of fibers. Over-beating would damage the cellulose fiber. A test equipment used for this process was a Freeness tester, a very simple instrument measuring the drainage capability of the pulp or paper mass. 

As mentioned, the Ocean Falls mill produced three major grades of pulp stock. Mechanical pulp, sulphate pulp and sulfite pulp. The sulphate and sulfite pulp was produced in batch digesters, large cooking vessels. The mechanical pulp was produced by grinding wood blocks in closed pulp wood grinders. The original ground wood grinder room was very old, dating back to the beginning of the mill. It employed a very primitive and manpower intensive process. The original ground wood grinders were quite small and they were 3 pocket grinders. Each grinder had three separate pockets  which the operator would fill with with relative small blocks of wood. Each operator had a small wood pile by the side of his grinder. The operator would load the grinder by opening a simple plate door. Once the wood was inside the pocket and the door closed, the operator would open a steam valve on top of the pocket. The steam pressure would drive a piston down on top of the wood thus pushing the wood against the large grindstone running inside the grinder. It was  necessary to cool this process with water to avoid burning the wood and to provide a final pulp slurry. The efficiency of the grinding operation was poor based on wood utilization. Towards the end of the grinding cycle there was a loss of wood since the very last wood in the pocket could not be ground properly. The grinders produced a lot of what was called slivers. These slivers were screened out and sent to a sliver pit. The grinder stones were large and heavy cylindrical stones made out of carborundum. They were artificial stones produced by a sintering process and they were grooved on the surface to provide good cutting. They would wear down with time and had to be re-grooved on a special machine. The pulp produced by this process is called mechanical pulp since in it's very basic form, the pulp has not been in touch with any dissolving chemicals or heat. Today, most mechanical pulp is produced in pulp refiners even if there still are mills using the stone grinding method. 

The old  Groundwood Mill could be compared to Dante's inferno due to it's layout, darkness. moisture and  steam escaping from the grinders. The floor of the operating floor was low and traffic through the grinder room was by catwalks about 12 feet above the operators. It was always an amazing sight to see these men working below in all the steam and water spray from the grinders. Such working conditions would most likely not be tolerated in any  industry today, and rightfully so. The mill's pulp and paper testing lab and offices for the technical department people was located in the Groundwood Mill. 

In the middle of 1960 the old 3 pocket grinders were replaced with modern "Great Northern" grinders, some driven by a water turbine and others by electric motors. The feeding of these grinders was now a mechanical process, the groundwood blocks coming in by a large conveyor.