Before the railroad made the transport of logs possible in the winter, the mill would shut for several winter months and the men moved to the logging camps up the Blackfoot. Logs would be floated downriver to Bonner for the next spring. After the railroad, the mill stayed open all year.
On January 16, 1919, the “greatest fire in the history of Western Montana” burned a large portion of the mill to the ground. Some 250 men were thrown temporarily out of work. The mill was rebuilt and running by the September of the same year.
W.C. Lubrecht became the general manager of the Anaconda Copper Mining (ACM) mill in 1925 serving until 1949. Automation gradually was introduced. In the early days horses moved the lumber around the mill, and the work was done by hand. As many as 50 men on one shift sorted lumber as it came into the mill called “pulling on the green chain.” By the 1960s there were only a handful working this job.
Working for the mill was not just a job, it was a life. Generation followed generation into the mill. Many boys went to work at 16, or even younger if they could get away with it. By the late 1920’s the basic laborer made $3.36 per day, while those doing saw work earned $5.00 per day, and the head sawyer earned $8.00. Men worked six days a week, and payday was every two weeks; in the early days it was once a month.
In 1928 Anaconda, acquired the adjacent Western Lumber Mill. Both the Depression and running two mills within ½ mile of each contributed to its closing in 1932. Most of the people who worked for the Western got hired by Anaconda so it was a fairly smooth transition. During the Depression, Anaconda tried to keep the work force together by only working three days or less.
In 1939, the Federal Writers Project: Montana State Guide Book described the Bonner mill's operation:
"The mill is a black frame shed, 300 feet long and 150 feet wide. Cat walks afford a safe view of the screeching, bellowing room; danger signs warn against going near the whirring machines. The logs, sawed into convenient, lengths before they leave the woods, are hooked out of the pond in the rear of the plant by an endless belt, set with ugly sharp prongs, that carries them to the three saw carriages; band saws on pulleys rip through them. Sawdust is carried off to the engine room where it feeds the big furnaces that generate steam to operate the machines. Endless chains carry the boards to the planing department where they are smoothed or made into shingles and laths; or to other departments for special treatment. On the top floor of the shed is the filing room, where band saws are filed mechanically. All over the mill the men work fast; they wear clothing without loose ends. The noise seems almost unbearable to newcomers. Between 1898 and 1938 the mill turned out 3,990,000,000 board feet of lumber. In an average eight hour shift the saws cut 420,000 board feet of lumber and the planes finish 200,000 feet. The annual shipment of mine timbers, wedges, and other lumber to the Butte mines alone is 40,000,000 board feet."
Labor unrest occurred around 1908 and again in 1917-19 when the Industrial Workers of the World (IWW or Wobblies) struck at the Bonner Mill. The union came into the mill in 1942 bringing better working conditions and establishing the principal of seniority. There was a 6 month strike at the Bonner Mill in 1946 between supporters of the AFL (mill workers) and the CIO (lumber camp workers) resulting in the AFL becoming the official union of the ACM Lumber Division.
In 1950, Anaconda policy shifted to “sustained yield forestry,” and the forestry division was reorganized. The stulls mill (supporting the mines) was moved from Bonner to Rocker, closer to the mines.
In the early 1960s Anaconda undertook a major $53 million modernization of the Bonner mill; the so-called. “push button” plant was dedicated in August, 1963 The mill now produced laminated beams and used more dry kilns instead of drying the wood outside. Over 700 men of the 9,000 Anaconda workforce in Montana were in its Lumber Division. As part of this expansion Anaconda tore out the generating plant associated with the Bonner Dam and electrified the mill using commercial electricity, purchased inexpensively from Montana Power (also associated with Anaconda.)
In the early 1970s Chile nationalized Anaconda’s copper mines, resulting in Anaconda being was forced to sell off its assets to raise cash. In 1972, the Bonner mill and 680,000 acres of timberlands were sold to U.S. Plywood-Champion Papers, Inc. The plant shut down for three months, and everyone was terminated with pay based on years of service. However Timberlands workers were hired to do an inventory of the trees on Champion’s new lands and several weeks before the mill started back up, loggers were hired so that there would be logs in the mill. Eventually, a large percentage of the mill workers were also rehired.
The ownership changed caused a big change for the community. Company policy now came from out-of-state. Supervisors no longer had to actually live in Bonner, due to the ease of transportation. The care ACM had taken in the company houses in Bonner, was less evident as was the involvement of the managers in the community.