Freerails Home 
Home Search search Menu menu Not logged in - Login | Register
Freerails > Model Railroad Forums > Narrow Gauge > Modeling the Gilpin Tram Part II

Because of non-railroad abuse of the site, new members MUST use their first names (at least) to join NO EXCEPTIONS!

Modeling the Gilpin Tram Part II
 Moderated by: W C Greene Page:  First Page Previous Page  ...  3  4  5  6  7  8  9  10  11  12  13  ...  Next Page Last Page  
New Topic Reply Printer Friendly
 Rating:  Rating
AuthorPost
 Posted: Tue Jan 10th, 2017 10:27 pm
  PMQuoteReply
71st Post
slateworks
Registered


Joined: Wed Oct 6th, 2010
Location: Twickenham, United Kingdom
Posts: 472
Status: 
Offline
Keith, I don't think I've commented before but I've followed the thread along and the research material has been brilliant. Now I'm having to fit a strap to my bottom jaw which keeps falling to the floor when I look at your actual model making. Absolutely superb and a real inspiration.:2t::apl:

Last edited on Tue Jan 10th, 2017 10:27 pm by slateworks



____________________
Doug
Updah Creek http://www.freerails.com/view_topic.php?id=7457&forum_id=4&page=1
My Flickr albums https://www.flickr.com/photos/33431492@N04/albums
Back To Top

 Posted: Wed Jan 11th, 2017 04:51 am
  PMQuoteReply
72nd Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline
Woodie, Si, and Doug, Yes, trackplanning continues, and I'll arrive at a solution soon. Other model activities continue, and I'll post on them as they are completed. Meanwhile... IN ICTU OCULI A Gilpin Tram Farewell
And in the blink of an eye, The Gilpin Railroad was gone! 
100 years ago, the Colorado & Southern Railroad sent a dispatch to the Gilpin Railroad on January 12, 1917,  and the Register-Call newspaper reported that it was
ordering all the tram cars, engines, and the other equipment, to be in the roundhouse of the company, by Monday, the 15th That date ends the control of the line by that company (the C&S), and the transfer of the line to Denver parties, who have bought the road, will be made later. Reports have bee in circulation that the new owners intend to operate the line if then can make it a paying proposition, and if the find to be a white elephant on their hands, the line will be scrapped, and sold as junk.
 
Unfortunately, the tramway could not be run profitably, and the Register-Call reported the $67,000 of company bonds had been sold to Radetsky Brothers of the Colorado Iron and Metal Company of Denver. After various legal proceedings, the final sale was made on June 2, 1917, to the Radetsky Brothers.  Thereafter, scrapping of the line proceeded. By October of that year, trackage had been ripped up back to Chase Gulch, and the final removals to the enginehouse completed a few weeks afterward.
 
Only a few remnants of the Gilpin Tram survived. The three shays, numbers 3, 4, and 5, were sent to Radetsky’s Denver scrap yard potential sale. There they sat for many years, with no buyers, and were scrapped in 1938. Twenty of the Tram’s unique ore cars were purchased by the Iron City Mill, and used to transfer ore from a nearby loading point to the mill. Initially, these cars were hauled by horses, and later an internal combustion engine. Everything else – rolling stock, rail, and machinery were scrapped. 
The Gilpin Tram originally had a bright and prosperous start, when, on December 11, 1887, the first ore shipments were made. The Gilpin Tram was a technological marvel in its day, efficiently reaching many of the major producing mines and reducing shipping costs. The tramway allowed lower-grade ores, formerly not economical to mine, to now be extracted for their ore.  
This prosperous little railroad did not go unnoticed. The Colorado & Southern Railroad recognized the traffic that the tramway could feed them outbound ore and concentrates, and inbound coal and other supplies. Also, new railroad construction to the north (the Denver, Northwestern and Pacific) was threateningly close, and there was talk of building feeder lines north from Central City to reach this standard gauge line. This could not be allowed, and so on June 27, 1906, the Gilpin Tramway Company became wholly owned by the Colorado and Southern. 
But, the mining industry did not stand still. As the mines grew deeper, removal of subsurface water became more of a problem. Innovations in drilling appeared, too, and soon, haulage tunnels from Idaho Springs could be built to reach to bottom levels of many Gilpin County mines, draining the troublesome water, and hauling out the ore. Although many tunnels were started, it was the Newhouse Tunnel from Idaho Springs that reached the mines. 
Ongoing expansion by the Newhouse Tunnel was now taking over more and more ore haulage from the producing mines in the district. Already, the tunnel had tapped former major shippers on the tramway, such as the Frontenac, Aduddell, Saratoga, Old Town, and others, with more mines being reached each year. 
As more mine shafts were linked up, less and less ore was hauled by the tramway. By 1914, former operating surpluses turned into losses. 1915 was no better, and 1916 even worse! The prospects for any future increase in traffic were none too good, either. By 1916, only the Polar Star Mill in Black Hawk was custom treating ores on a regular basis. What had started out as a European war in 1914 had ominously grown, and now seemingly engulfed the whole world. This impacted mining operations, too, and precious metal mining had dropped off precipitously in 1914. 
The handwriting was on the wall – the outlook was poor, and it was time to end operations. So, with very little notice, the Gilpin Tram faded away into history.       

Last edited on Wed Jan 11th, 2017 04:53 am by Keith Pashina

Back To Top

 Posted: Wed Jan 11th, 2017 06:33 pm
  PMQuoteReply
73rd Post
Chriss H
Registered


Joined: Sat Aug 13th, 2016
Location: Plano, Texas USA
Posts: 87
Status: 
Offline
The end of the line was sad for the Gilpin Tramway. In thinking it over though, I may choose to model a post Gilpin Tramway RR where the economy is improving, and they are branching out and adding more updated equipment. Could be interesting, I'd do the entire Gilpin if I still had my old house with the 2500 sq. ft basement, but now I'm stuck having only a small module or two to place on shelf brackets in my single room.

R.I.P. Gilpin Tram 100 years ago tomorrow (Thursday).



____________________
_______
Chriss

I'm a Colorado mining district afficianado. Planning a layout in HOn3 based on the Gilpin County area.
Back To Top

 Posted: Mon Feb 13th, 2017 03:31 am
  PMQuoteReply
74th Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline
It's been a busy, but fun winter so far. But, time to get going on my model railroad planning, and along with that, further investigating the what and how of the Black Hawk mills, town, and Gilpin Tram trackage.




The map above shows the remaining portion of the Gilpin Tram route that we'll be looking at. The Part 2 continuation of the Gilpin Tram thread has previously looked at the Fullerton Mill branch, which served the Wheeler, Upper Fullerton, and Brooklyn (Golden Fleece) mills. This thread also looked at the engine house and yard area.  Last we were looking at the Hidden Treasure Mill, a very interesting mill in many respects. 

Back To Top

 Posted: Mon Feb 13th, 2017 03:43 am
  PMQuoteReply
75th Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline
Gold Ore Processing in the Black Hawk Area
 
The whole point of the Gilpin Tram was to economically haul gold-bearing ore down to the ore-processing mills located in Black Hawk. The railroad drastically reduced the cost of hauling ores down by horse-drawn wagons. But more importantly, the railroad allowed lower grade ores that had previously not worth enough to justify haulage by wagons to be hauled by rail.
 
Gold ore processing methods changed over time, in part due to changes in the ore chemistry, and in part due to advances in technology. For the time period I am interested in, when the Gilpin Tram operated, the ore handling methods used were similar at the various mills near Black Hawk.
 
During the first mining booms in Gilpin County, the miners were at first encountering free gold near the surface, and when they started pit or shaft mining, were encountering surface ores,  which were for the most part oxidized and easily milled using stamp mills and amalgamating tables. The “Mining and Scientific Press” on December 4, 1921, reported that the first homemade wood stamp mill was built in 1859, and a later that year a “modern” imported 3-stamp plant was erected. This technology took off fast, and there were 60 stamps in operation by 1860. But, as the mines deepened, the ore chemistry changed to containing more and more sulphides compunds. This was a disaster at the time. While the milling practices had been able to recover as much as 75% of the gold formerly, the same equipment did not work well on the deeper sulphide-containing ores, and the recovered gold contents at the mills dropped precipitously, to 30% or less!


The above section shows what could be considered a typical stamp mill for precious metals - at least as far as we modelers are concerned. However, the typical mill, one that cascades down the hillside, was not that common down in the Black Hawk area
 
The solution to the previous milling problems was studied by several ingenious inventors and tinkerers who eventually developed a modified process that was customized for the Gilpin County gold-bearing ores. These processes are more technical than what I, a non-mining type person, can fully understand. And, since my interest is a hobby, not professional, I cannot nor do I need to know all of the intricacies of how the ore was processed. However, what I am interested in knowing is:
 
·       Basic knowledge of how ore was processed, so I can understand how the mills were laid out and constructed, and,
·       What machinery was inside the mills, so I can build models of it
 
So, with some simple parameters set, let’s look at the how and why of the gold ore processing milling practices near Black Hawk.
A disclaimer: I will greatly generalize, and simplify, this discussion. I know several regular FreeRails readers have mining backgrounds, so if any of you would be kind enough to offer more detail and information, please do so!


In previous posts, we looked at the Hidden Treasure Mill. This mill had many interesting features that would make a fascinating model. We will look at this mill even closer, because several mining and technical publications in the early 1900s also provided a lot of information about how this mill operated.


This is a somewhat modified excerpt from an 1895 Sanborn Fire Insurance Map. This map was apparently drawn when the mill had grown to 75 stamp heads. This was a drastic enlargement from its earlier history, and in later years, was modified further


Back To Top

 Posted: Mon Feb 13th, 2017 04:00 am
  PMQuoteReply
76th Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline
ORE PROCESSING IN THE HIDDEN TREASURE MILL - AN EXAMPLE

This image shows a very simplified flow chart of how ore moved through the Hidden Treasure Mill. This could be considered a snapshot in time, because the process evolved over time, as ores changes and the equipment or flow of ores needed to change. This flow chart represents the mill when it was at its peak production, and about the time most photos were taken of this mill
The first step was to unload the ore, and get it ready to feed into the stamp mill. In most cases, this consisted of dumping Gilpin ore carloads directly into ore bins, or sometimes into piles on the mill floor.  The ore had already been sorted out at the mine, and only ore with good values would have been shipped by rail. Some pieces were too large for the stamp mortar opening, so these were broken into smaller pieces using mauls and sledge hammers. From what I have read, no mechanized crushing was used here, such as jaw crushers, as used in other mining districts.  
The basic idea of a ore-processing mill is to break down the raw ore into smaller pieces, to liberate the gold (and other metals) and somehow concentrate it so it can be sent to a smelter for final processing. As we mentioned before, conventional stamp mills did not work well on the ore with higher amounts of sulphides. The technological breakthrough was the “Gilpin county stamp mill”. At first glance, it looks like a conventional stamp mill: 5 stamp heads lifted by tappets and grabbers, a mortar box the ore is crushed in, and a big wheel for the belt drive. But, the big differences are: 1) the stamps were lighter and dropped much slower and 2) the mortar box deeper and larger.


One piece of equipment you rarely saw in a Black Hawk mill was a jaw crusher, such as shown above. Although common in mills in many other districts in Colorado, these crushers were generally not needed at the Black Hawk mills. Each mill seems to have a customized set of equipment and ore handling methods, and no two seem to be alike. But, there seems to be an exception to every generalization that I make, so a few of the mills did have jaw crushers!  That said, labor was cheap, and hand breaking-up of ores and shoveling of ores was the preferred practice


Just for fun, I included this photo of a modern-era jaw crusher, from above. Note the electric motor at right - not common at the era I model, the early 1900s. The ore feed was from left to right, and ore slid down the chute at left into the top of the jaw crusher at center


Here is the "guts" of the Hidden Treasure Mill - the large bank of stamp mills - at least 50 stamp heads are visible here, and there were 25 more not shown in the mill not shown in this photo!  One thing that strikes me in these and other photos are the crowded nature of the mill - there is a lot of machinery, walkways, launders, belt drives and structural members all over the place. This would be a challenge to model, but very rewarding if pulled off correctly!










Back To Top

 Posted: Mon Feb 13th, 2017 04:11 am
  PMQuoteReply
77th Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline
These stamp mills were fed by hand-shoveling the ore in the rear (ore bin side) of the stamp mill. From what I have been read (and told by those individuals who would know this stuff), no mechanized ore feeders were used in the Black Hawk mills.
 This is a flow chart I used in a presentation the 2014 Narrow Gauge Convention, and shows part of the ore handling methods. The stamp battery (the stamp mill machine in side the stamp mill building - whew! confusing, isn't it?) was probably the most important part of the mill. This machine did two critical steps, and until alternative crushing methods became more popular, this was the "Gold Standard" process (sorry, I couldn't resist the pun)


This is what a Gilpin County stamp battery looked like. This restored example sits in front of the Gilpin County Historical Society Museum in Central City. Note the gear drive on this mill (some had wooden bull wheels)


This image is representative of a stamp mortar battery - a cast iron box where amalgamation and crushing took place. These objects were heavily built to withstand the crushing forces and vibrations


Each stamp mill had 5 stamps each, and stamp mills were ganged up to attain whatever capacity the mill needed to handle. So, the Wheeler Mill had 40 stamps, meaning they would have had 8 stamp mills inside, and the Hidden Treasure Mill had 75 stamps – 15 stamp mills, at its peak production.
 
The stamp mills did vary, depending on each mill’s preferences. Some representative sizes were:
·       550# - the weight of each stamp head
·       18” – the drop height of each individual stamp head
·       30 – number of drops per minute
·       18” – depth of the mortar box
 
By enlarging the mortar box and slowing down the stamping, the ore was crushed to a smaller size, and stayed longer inside the mortar box, Unlike other stamp mills, that just crushed the ore, the Gilpin county stamp mill also used amalgamation inside the mortar box. The ore was gradually crushed and churned around in the mortar box by the stamps, along with the mercury. Some of the gold consequently adhered to the mercury that was on the amalgamation plates, and was cleaned off later. The remaining ore, after some time, eventually was small enough to pass out through the exit screen, and on to the third step of the process – more amalgamation tables.


The rear of a stamp battery - the narrow slot is where the ore was shoveled in, by hand, of course


The "front" of the stamp  battery - although slightly ajar, you can see the screen at the front of the stamp battery - the ore had to be crushed very fine to pass through the small sieve openings




Back To Top

 Posted: Mon Feb 13th, 2017 04:15 am
  PMQuoteReply
78th Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline

One thing to note - I have been told by knowledgeable people in the mining industry that mechanical ore feeders, such as shown here, were not used in the Black Hawk mills. This innovative machine was tied to the action of the stamp hammer cams, and mechanically get ore into the small slot at the rear of the stamp battery

This is a side view of mechanical ore feeders, not common in Black Hawk, but used elsewhere. These two photos were taken at the Argo Mill museum display in Idaho Springs
So, so far we have seen the crushing machinery and first steps in ore processing. But, there is a lot more going on inside a mill. Next, we'll at what happens next in the flow through the mill.
Keith



Back To Top

 Posted: Fri Feb 17th, 2017 05:20 am
  PMQuoteReply
79th Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline
Ore Processing: Amalgamation Tables and Blankets

A view of two stamps, with amalgamation tables in from of the stamps. I think parts of the mortar boxes have been removed here - normally, a narrow slot with a screen would be in front of the stamp heads
After crushing the ore in the stamp mill, a common practice was to run the mixture of finely crushed ore and water over first amalgamation tables, and then (but not always) blankets.
 
Amalgamation, at least as used in the Black Hawk mills, refers to the amalgamation of mercury with gold (and sometimes other precious metals).  This basically involved preparing the amalgamation table  and plates. As mentioned before, the stamp mortar box was used for both crushing and amalgamation. The stamp mortar box typically had copper plates at the front and rear of the mortar box. In front of the stamp mill, the amalgamation table was more or less a wooden or metal trough, with copper plates. Mercury would be applied by workers spreading it out with wooden paddles – the mercury would adhere to the copper plate.  Mercury was a consumable item – one source reports about 1/5 ounce of mercury was consumed per ton of ore stamped. Although most of the mercury was recovered and reused, some just “disappeared” out the mill – into stamp wastes or into Clear Creek.
 
When the slurry mixture of finely crushed ore and water ran across the mercury, the free gold, that is, gold not chemically bound to other minerals, would adhere to the mercury.


This amalgamation table is a display at the Western Museum of Mining in Colorado Springs

After passing over the amalgamation tables, some mills also had “blankets” – these were exactly what you think they were. A typical “blanket” was strips of 18” wide by 36” long strips attached to a sloping wooden table. The slurry ran across the blankets, and some of the amalgam which escaped from the amalgamation table was collected in the blankets. In the Hidden Treasure Mill, these strips were removed and washed of the amalgam every 4 hours. In a model, these would probably look similar to an amalgamation table, although I have never seen a photo of one.
 
 
Periodically, the stamp mill would be stopped, and workers would scrape off the amalgam – the mercury and gold mixture from the amalgamation table and mortar box.



An amalgamation table on display at the Argo Tunnel and Mill in Idaho Springs


The amalgam was collected, and then put into a retort oven or pot, where the amalgam was slowly heated until the mercury began to boil off. This was an extremely hazardous process – mercury vapors are poisonous. The sealed-off retort vented into a long tube, which was cooled by water. The water quickly cooled and condensed the mercury, which was collected and reused on the amalgamation tables and stamp mortar boxes.
 


Inside the retort oven/pot, was a “sponge”  was left inside the retort. The sponge was the gold, but with a spongy like structure, from where mercury had been boiled off. The heat was not sufficient to melt the gold completely. The sponges were collected and locked up, and later melted into bullion bars.






Next, we will look at ore concentrating tables: Gilpin County Bumping Tables, Deister tables, and Frue Vanners.


Keith

Back To Top

 Posted: Sun Feb 19th, 2017 05:02 am
  PMQuoteReply
80th Post
Keith Pashina
Registered
 

Joined: Sun Nov 4th, 2012
Location: Minneapolis, Minnesota USA
Posts: 609
Status: 
Offline


The inside of the Hidden Treasure Mill, showing the stamps and amalgamation tables at the rear, with a line of Gilpin County Bumping Tables in front, used to concentrate the ore's metal content further
CONCENTRATING TABLES
 
After moving through the stamp mills, amalgamation tables and mortar boxes, and blankets, the ore slurry moved to concentration equipment.
 
For the time period I am interested in modeling, a limited amount of processes were used to concentrate the ore.  In later years, that is, after about 1900 or so, other processes were introduced into the area mills.
 
The Black Hawk mills favored a concentrator called, naturally enough, the Gilpin County Bumping Table.  If you’re familiar with gold panning, you basically separate the gold particles from the sands and gravel by agitating a mixture of rocks and water. The lighter density quartz and other minerals wash away first, leaving the heavier gold behind. The bumping table used a similar concept, although mechanized.

Generally, a Gilpin County Bumping Table was like a gently sloping metal sluice flat on the bottom. Ore slurry was introduced at one end of the table, and it was bumped back and forth (front to back), about 1 ½ to 3 inches 2 to 3 times per second. The bumping action moved the heavier gold particles up the slope to the front of the table, and the water would wash the lighter particles down to the bottom of the table. This table was developed and manufactured locally, and doesn’t seem to have very popular outside of the county.
 
Photos of mills show that 2 or more tables were paired with each stamp battery. The Hidde Treasure Mill, for example, had 20 tables, in 10 groups of 2. Modeling these tables would be a challenge, as to my knowledge no commercially made kits have ever been offered by anybody. However, these tables are also a key, distinctive feature in almost any of the mills, and worthy of being modeled.

Another concentrator used alongside the Gilpin County Bumping Tables was the Frue Vanner. This machine was first manufactured in the 1860s, and introduced in the Black Hawk mills in the late 1800s.  The term “vanner” comes from the word van, which means to wash ore on a flat shovel. The Frue Vanner differed from a bumping table, in that there was a gently sloped continuous belt shaken from side to side (whereas a bumping table was bumped back and forth).  Some sources say a large vanner was about 14’ long by 9’ wide and sat about 5’ tall, and the belt itself about 4’ wide by 12’ long. A smaller vanner had 4’ wide belt. The table was shaken side to side about 1”, and the belt rotated and moved about 3’ per minute. The lighter, non-metal waste separated to the top and was gradually washed away, and ore concentrate stayed on the table, moved to the end of the table, and was collected.


 Above, a Frue Vanner


Another popular concentrator was the Wilfley table, invented in western Colorado in the late 1890s. The table shook back and forth, and a series of riffles on the surface aided in separating light waste rock from heavier mineral concentrates. Probably more common in other mining districts, some Black Hawk mills did use them. This is good news for modelers, because kits have been offered in O and HO scales, and maybe others, too.




 
Yet one other concentrator used was Deister table. This was used in some mills, and looks similar to Wilfley or other tables. There is a side mechanism that actuates the shaking action, where Wilfley tables seem to have this mechanism on the narrow end. To model one, perhaps a Wilfley table kit could be used.
 




`Remember, I am greatly simplifying the explanation of how the mills worked, but for my purposes, I really don’t need to know all that much, just enough to make a plausible model. Although there are many very technical methods and adjustments going on in a mill, miniature models, at least in the smaller scales, don’t need to show all the nuances.

There is a lot more going on in the mills, and we’ll look at some of the other machinery next.


Keith

Back To Top


 Current time is 05:43 am
Page:  First Page Previous Page  ...  3  4  5  6  7  8  9  10  11  12  13  ...  Next Page Last Page  

Freerails > Model Railroad Forums > Narrow Gauge > Modeling the Gilpin Tram Part II
Top



UltraBB 1.172 Copyright © 2007-2016 Data 1 Systems