The company decided in 1960 to increase its paper production dramatically. PM4 started operations in 1963 in a fully integrated production line manufacturing supercalender magazine paper, with an annual production of 50,000 tonnes. This involved the installation of a new lumber cleaning and chopping mill, a new pulp mill, a new boiler system and a new water pipe from Femsjøen. Steam from the Halden Reactor was used in the paper machines. Saugbrugsforeningen thus became the first paper mill in the world to derive steam from nuclear power. Investments from 1958 to 1963 cost NOK 165 million. By 1964 the company was producing 130,000 tonnes annually of various paper grades, up four-fold since 1950. The company had 3,000 employees, of which about 1,000 worked in the forests.