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Keith Pashina
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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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slateworks
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Keith, I have to say this is an ongoing and fascinating education on a subject I knew nothing about until I found your thread Mks.1 and 2. Superbly researched and presented. Last edited on Sat Apr 1st, 2017 10:36 pm by slateworks
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Doug
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| Posted: Thu Apr 13th, 2017 07:07 am |
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Keith Pashina
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Some Thoughts On Mill Interiors & Modeling Them
An example stamp mill (not Gilpin County), showing the typical design that descends down the hillside to take advantage of gravity, and general building framing, belt drive, and machinery locations
As I prepare to start modeling some ore processing mills for my Black Hawk scene, I thought I would review some of various parts of the overall mill interior that would help make a convincing and realistic model.
Depending on the mill I am modeling, the interior foundation walls might either by laid-up rubble stone, or "modern" concrete. Where modeling concrete, a nice detail is the marks left from the individual boards used to form up the concrete (this photo taken inside the Argo Mill in Idaho Springs)
This photo shows a Wilfley Table in the Santiago Mill near Waldorf on the Argentine Central. Two things jump out at me in this photo - first, note that the floor is dirt, not wood or concrete. Second, notice all of the various piping and launders (small flumes) serving this table.
Next, here is the Mendota Mill in Silver Plume. This is an example of a small mill, and the overall design is ratter flat, not cascading down the hillside, and maybe this building shape is more typical of the mills in Black Hawk. Also, I like the weatherbeaten look of the metal siding
This image was taken inside the Western Museum of Mining near Colorado Springs. This is a very important, and fun thing to model inside a mill model - the overhead belt drive that would serve the stamp batteries, bumping tables, Wilfley tables, and other machinery. Also, note how robust the wood building framing is - the pounding of the stamps was hard on buildings, and they had to be robustly built
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| Posted: Thu Apr 13th, 2017 07:17 am |
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94th Post |
Keith Pashina
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This photo is back in the Santiago Mill near Waldorf. This photo reminds of something Mike Condor told me about mills - they were very dirty inside. The ore crushing, slurries, slimes, and dust eventually coated everything, making machinery, walls, and framing all dirt-covered. The dirt color would be that of whatever ores were being processed - in Black Hawk, that would be a light gray. So, an excuse to do very heavy weathering inside a mill - that is fun to model!
This was taken inside a modern mill near Central City, and what stands out in this picture is how cluttered the mill interior is. If this was an older mill, there would be belts and belt drive wheels and axles cluttering up the interior even more. Even though this mill had electric motor-driven machinery, there are still water feed pipes, launders, sluices and flumes, and wooden building framing all over the place.
This review of photos has reminded me to build models from the prototype, and not photos of other models. I will want to go for the dirty, cluttered, busy look in whatever mill interior I get around to modeling. Looking at past model magazine models, a lot of the models pictured seem to be to barren inside and too clean.
Not all machinery in a mill was massive. This cleanup pan in a modern mill (it was driven by an electric motor) is about the size of an old style clothes washing machine. This could easily be driven by an overhead belt and pulley drive system. Also note the machine and floor are covered in dirt and crud
So, that wraps up my thoughts on mill interiors, and next, we'll continue a review of the mills that existed Black Hawk during the Gilpin Tram era.
Keith
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| Posted: Thu Apr 13th, 2017 10:36 am |
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| Posted: Fri Apr 14th, 2017 07:20 pm |
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Herb Kephart
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Keith
Just one word--EXCELLENT!
Herb
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Fix it again, Mr Gates--it still works!"
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| Posted: Fri Apr 14th, 2017 07:29 pm |
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97th Post |
slateworks
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A new lesson every post thanks Keith. A super piece of illustrated research.
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Doug
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| Posted: Fri Apr 14th, 2017 10:47 pm |
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98th Post |
W C Greene
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Keith, I have written this before and will once more...THANK YOU FOR THIS! There is no other place I know of which has this much in-depth information. Not only does this spotlight the Gilpin Tram but anybody wanting to build an accurate model of a mine, mill, smelter, should appreciate the thread. We are indeed fortunate to have you here. And we can always stand more...much more!
Woodie
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It doesn't matter if you win or lose, its' how you rig the game.
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| Posted: Mon Apr 17th, 2017 01:51 am |
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99th Post |
Chriss H
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| Location: | Plano, Texas USA |
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Keith,
Fantastic shots and informative writing on the insides of those stamp mills. Looking forward to Aug/Sept Narrow Gauge convention in Denver (about 3 miles from where I grew up). Are you still planning on attending? I will have my pickup truck so a side trip to Gilpin county will be in order!
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Chriss
I'm a Colorado mining district afficianado. Planning a layout in HOn3 based on the Gilpin County area.
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Keith Pashina
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Well, it's been fun posting and sharing information about the Gilpin Tram. My previous posts discussed the mill machinery and what generally happened inside the Black Hawk Mills. Now, it's time to continue the intermittent journey down the Gilpin Tram. The previous posts left off at the Hidden Treasure Mill.
THE HUMPHREY AND MEADE MILLS
Following Clear Creek downstream, we encounter two more mills that were literally “just around the bend”. From the Hidden Treasure Mill, the main trackage was dual gauge 2’ and 3’ all the way to the south end of Black Hawk. Along the route, there were some dual gauge side tracks, as well as individual 2’ gauge and 3’ gauge spurs.
The next mill that sat next to the Gilpin Tram was the Humphrey Concentrator. This mill seems to have followed a typical practice of the time in regards to milling machinery used in the mine. The 1890 Sanborn Fire Insurance Map refers to a rolls and crusher, sizing screens, 20 stamps, and revolving buddles. There is not much information I could find out about this mill. The 1890 Sandborn Fire Insurance Map shows a spur from the Colorado Central 3’ gauge to this mill. The 1895 and later Sanborn maps don’t show this mill. Also, I could find no references to it receiving any ore from the Gilpin Tram or by other means. My opinion is this mill closed down probably by the turn of the century.
The Humphrey Mill (also called the Humphrey Concentrator) back when it was operating - not the steam exhaust from the roof vent pipe. Notice that big square stack - we'll see more of that later. This mill apparently never received any ore from the Gilpin Tram
This is the 1890 Sanborn Fire Insurance map showing the Humphrey Mill. Note the 3' gauge Colorado Central spur which served the mill at the time. This seems to have a been a very active mill operation at one time
Here is a later view looking upstream at a high-water Clear Creek, with the C&S bridge. By this time, the Gilpin Tram had shut down and the 2' dual gauge removed. The Humphrey Mill is at the right hand side of this photo. The mill looks inactive, and rather dilapidated by this time
By the 1980s, all that remained of the Humphrey was some foundations and the brick smokestack (which you could clearly see in the previous photos showing the mill when operating). The City of Black Hawk chose to remove this "eyesore" sometime in the 1990s, dug out part of the hillside, and used this space for parking for a while
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