This is an article from a Denver Mining equipment manufacturer on the history and evolution of methods of ore extraction and processing. The descriptions are quite detailed and fairly sophisticated for 1936. The mechanical and chemical process were quite amazing. This book was a every thing you needed to know book on how to build a Colorado mill. They started with a bare ground lot and walked you through the entire building process. I thought some of their cost estimates were amazing.
Roads and Clearing $.75 per yard
Excavation $.50 per yard
Foundations $20,00 per yard
Lumber $40.00 per thousand board feet
Roofing $8.00 per 100 square ft.
They did a item by item cost analysis and then projected the different quantities and qualities of ore that would need to be processed to turn a profit. Also included were log tables, weights and measure conversion charts, mineral compositions, board ,barrel and pipe measures, and a lot more, This was all a little dry reading but the best part was the history of the actual milling process.
It is a wonder that they figured out how to separate gold and silver from the gangue and rock particles by introducing a sulfide mineral particle, pumping air into the mix and then having the other minerals adhere to the bubbles and float to the top, Gold and Silver floating?.
I will put each page as a thumbnail to save load time.