According to the 1920 United States Federal Census records, Henry K. Doll was born about 1871 in Germany and immigrated to the United States in 1888. The 1920 census also lists his occupation as blacksmith. His wife was named Carrie and his three children were Carrie, Mary, and Henrietta. Peter Steele, originally from Scranton, Pennsylvania, was born about 1866 according to the 1930 census. He died in Boise on January 2, 1938 and was buried at Morris Hill cemetery two days later. August Grete, who came from a local Silver City family, was born about 1861 to parents John and Mary. The 1900 U.S. census lists his wife Ella and son Lewis. Grete moved on to Portland, Oregon by 1920, and died on October 28, 1949 in Merced, California.

The earliest letter in the collection is dated to 1909. In his letters, Peter Steele wrote that in the early years the Banner operated with the aid of only three laborers and little equipment, including a compressor. August Grete supervised matters at the site in Silver City, while Peter Steele traveled about the Midwest. Steele tried to sell stocks and bonds to new investors in order to purchase more equipment and add more men to work in the mine until it began paying. He was unable to find much success in Minneapolis, Duluth, or Red Wing in Minnesota. Meanwhile, the power was cut off at the mine for long time due to low funds. This did not dampen his optimism regarding the potential output of the mine, however.

With little luck in Minnesota, Peter Steele moved on to Wisconsin. He worked in Superior and Milwaukee with continued disappointment. Muncie, Indiana did not aid his work either, while more struggles found the Banner Mine in Silver City. In January 1915, the water supply for the mine froze up and slowed progress for a time. However the Banner pushed on, buying a nearby mine and adding another laborer to the payroll.

Steele returned to Silver City and aided with the labor in the mine. It is noted that August Grete ran the compressor, while a worker named Duggan ran the dirt out and Steele ran the machine drill. In 1915, Grete left for a job at a more prosperous mine, but this did not deter the Banner. Later on that year the mine hit a "good deal" of ore according to Steele's letters. The Banner was recovering about one ton of ore per day by 1916, Peter Steele stated. Also, Vice President F. S. Heer took over as secretary-treasurer around that time.

Unfortunately for the Banner Mining and Milling Company, more problems awaited them. In 1916, they hit water in the mine and on August 20, 1917, Steele wrote that, due to low funds, mining work stopped. The workers made $3.50 per day and wanted more but Steele would not pay because he did not believe the mine could afford it. So, the men quit working. It seems that the men had already worked a great while without pay because they trusted in the potential output of the mine, with some taking out stock in the mine instead. The work stoppage apparently lasted the1917-1918 winter. There is no mention of how the situation was resolved.

In 1918, the Banner Mine hit gold and quick silver, but it is not stated exactly how great the amount is. Throughout the letters written by Peter Steele, he repeats that they had a very difficult time making mill runs with the ore. Initially, Steele wanted to wait on a mill run until they could keep the mill running continuously but it doesn't appear that they were able to accomplish that.

Following a major flu pandemic that swept through Idaho in the winter of 1918-1919, a snow slide hit the Banner mine in spring 1919, destroying the mill and killing a mule. No one was injured in the slide, but it severely set back the mine's progress. Seven men worked at cleaning up the mine from the snow slide. Soon after that the letters trail off and the final document included in the collection is dated to 1923.