View single post by Keith Pashina
 Posted: Sat Apr 1st, 2017 09:23 pm
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Keith Pashina

 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 733
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Another grinding piece of equipment used were the Chilean and Huntingdon Mills. The Chilean mill had three heavy metal wheels grinding ore at the bottom of the pan. Huntington mills worked similar, but the wheels were horizontal rather than vertical as in the Chilean mill.
 
I have not seen commercial kits for any of this grinding equipment, but it would look great in a mill, or as a flatcar load.




A Chilean Mill on display at the Couer D'Alen Mine at Central City




This top view of a Chilean Mill, this one at South Park City near FairPlay, showing how slurry and slimes were fed into the top of the mill






A Huntington Mill worked similar to a Chilean Mill, but the grinding wheels were set horizontal, not vertical. I have seen a dismantled Huntington Mill on top of Quartz Hill, and may have been part of the Chain-O-Mines operation that came along after the Gilpin Tram quit running




A Denver Quartz Mill was similar to a Chilean Mill - the outside tank cover has been removed in this add, and shows the machinery mechanism clearly
CLEANUP AND AMALGAMATION
 
Other equipment used in some districts, maybe Gilpin County, were cleanup pans – these seem to be smaller than Chilean Mills, and either dragged flat stones around a circular pan, or heavy wheels, to further grind the ore concentrates.
 
The ore concentrates, after grinding to the right time, mercury was added to amalgamate with the gold and other metals. After working further, the water and waste was drained off, the amalgam collected, strained, and then sent off to the mercury retort to gather the metals and recycle (most of) the mercury. I think some manufacturers in the past have offered clean up pan kits. Currently, Wild West Scale Model Builders offers a kit of a horizontal one in multiple scales.
 
 
These mills were used as one of the final processes of finely ground concentrates, used to work on the material that the previous amalgamation tables, blankets, bumping tables, and others couldn’t trap.
 
FINAL CLEANUP
 
So, that will wrap up my brief, simplified explanation of how the Black Hawk mills processed ore in the era the Gilpin Tram ran. This over-simplified explanation has been kind of like saying you fly a rocket to the moon by pointing the nosecone at it and lighting the rear end!  But, models of this stuff don’t actually have to do anything – they just need to look plausible, and I hope my discussion here has helped with that.
 
I’ll next post some more thoughts on the mill buildings themselves, and then get back to a detailed mill-by-mill look at Black Hawk and the Gilpin Tram trackage.


Keith

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