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.
Amalgamation, Concentration and Bulk Flotation
Selective Flotation and Separation
Cyanidation and Crushing
Secondary Crushers and Grinding Mills
Ball and Rod Mills, Classifiers and Screens
Spiral Screens and Flotation Reagent Feeders
Conditioners for Floatation and Floatation Machines
Agitators for Cyanidation, Agitators, and Thickeners
Pumps and Filters