[blackburn49]

John J, I did not forget your question: "Speaking of Mines. When was the last time any one has been down in the Tunnels of the old copper Mine? Most of them should have caved in by now maybe?"

I was trying to decide what to do with this question. It seemed best to wait until Shad restored our new forum. We did not have a long wait, did we?  

Well, you know me. I don't like to start a thread unless I'm going to go somewhere with it. I am one of those "handful" of MLS members who creates "substantial" threads. Your question warrants more than a single one or two sentence response.  And so it will be. Those not interested in history need read no further.  You will not learn much about  model trains or structures  in this thread--although I have some great historic prototypes coming up. After all, I probably have the largest collection of historic Kennecott photos to be found anywhere.

I have written extensively about Kennecott, the Copper River & Northwestern Railway, and my Phase I CRNW layout.  But I have not adquately covered the mines themselves.

I have noted that more than once you, John J,   have expressed an interest in the old Kennecott minesite(s) that exist here in Alaska, so I will provide you and whoever else might be interested some background on this, one of the most fascinating of historic western mines for any number of reasons.

Some of you will recall that Kennecott was an interior group of mines that was only made possible by the construction of a 195-mile standard gauge railroad. This was the Copper River & Northwestern Railway, which operated concurrent to the mine from 1911 until the mine closing in 1938. The CRNW, while primarily an ore-hauler and supply line to the mill site, also operated as a common-carrier, providing freight and passenger service to the territories it opened up from the port of Cordova through the Bremner gold mining district, to Chitina and McCarthy and a host of other places. It was the first Alaskan railroad to breach  the Alaskan interior from an ocean port. And, like the White Pass & Yukon, the narrow gauge which entered the Canadian interior through an Alaskan port, this one was built by the same contractor and overseen by the same engineer.  Both represented major engineering achievements, but the CR&NW more so because the obstacles faced by the latter line were far more difficult, even considered impossible by some.

But this is not a railroad thread. It is about the historic mines themselves--the richest high-grade copper ore veins ever found to this day--and the ones which made Kennecott a household name. 


The abandoned Kennecott mill site in 1982 with Bonanza Ridge in the background.  Click to view this in a much larger size.

 

[sheepdog]

One line response..... Don't stop now Ron.

Second one line response..... I too am very curious on the state of the mines...

*grin*

 

[blackburn49]

Hey! One of my favorite posters. Hello, Craig.  Not to worry. I just need some time to pull my resources together here. And, unfortunately, I have a few other tasks which have to be performed today.

I am going to pull up some of my maps of the actual underground workings--the ones which can be posted on line. These are best seen in the larger size since they are so complex, but I will, of course, reduce them so they can be seen right here.

Additionally, I want you all to see the actual buildings at the mine adits--there were five separate sites--all interconnected. Some of these were substantial. Almost none of them exist today. 

So, hang on and I will get back to this. 

 

[sheepdog]

I keep trying to reply and it keeps deleting my post.....

Take your time Ron, I enjoy reading all the posts. And I want to add, that model of the brick is first rate!

Craig

 

[John J]

Thanks for your  special reply.   I really enjoy all your post.   

I also find bandon buildings ( especially industrial) most facinating.   I wish I could come up there and explore.

I set this thread to let me know when you post again.  

I know you have a lot to do to get ready for "THE SEASON"  

 

[blackburn49]

Bonanza--Where It all Began . . .
Looking up the aerial tram toward the Bonanza Mine in 1917 (click for larger image)
How many times have I said that? "Where it all began."  This was the place. It was here that the initial discovery was made and the mining claim laid. This was the very first of the Kennecott mines in what would turn out to be a long string of them around the world. For me personally, this was the place I first recognized through this very photo as it appeared in Lone Janson's "Copper Spike" many years ago as a place that I knew was somehow a part of what I am or what I was. 

This was the start of all of it--a lonely mine at the elevation of 6,000 feet along the southern slopes of the Wrangell Range.  And this was what launched Kennecott to world status because of its incredible richness that just never seemed to end.

By the time the original Kennecott Mines Company began working the Bonanza site they had already begun scoping out the Jumbo and Erie claims, knowing that soon they would be developing mines in those places as well. Within a few years they would also add the Mother Lode and the Glacier mines. 

The mines ran along a roughly west-north-west axis for a distance of approximately four miles.  And in time all of these five mines would become connected underground.

 

[blackburn49]

The Kennecott Mines Contour Map
The Historic American Engineering Record Recording Project produced this map in the early 1980s fro the National Park Service and the Cordova Historical Society. It shows the relationship of all the mines to the Kennecott mill site at the end of the railroad. You can also see a wagon trail which continued on to the base of the Erie Mine. The two main trams were the Bonanza and the Jumbo--both approximately 16,000 feet long.

The Bonanza Ridge in this map runs roughly left to right with the Mother Lode on the other side of the ridge--facing east.  All the other mines faced west. Mother Lode, which started as a separate company, had its own tram line to a base point on McCarthy Creek.  Erie and Glacier mines also had trams, although the Erie tram was only for men and supplies. All the Erie ore was sent through a long cross cut tunnel to the Jumbo incline shaft where it was trammed to the surface and then sent down the hill to the back of the Kennecott mill.

Click map for larger one

 

[blackburn49]

The Kennecott Map Showing Kennecott and Mother Lode Claims
This map, properly oriented north, was drawn by the very last superintendent at Kennecott, Walter Richelsen, in 1924 in advance of a visit by the Big Man himself, Stephen Birch, head of Kennecott.

You can actually see part of the main crosscut tunnel drawn between Erie and Jumbo. Click for a larger image.

 

[blackburn49]

The Cross-Cut Tunnel
I took a part of the contour map shown in the previous post and added some of the significant tunnels. We will be most interested in the main upper cross-cut tunnel seen here in dark red. It extends from the Erie main adit on the far west end of the claims to the eastern limit of the Mother Lode claims where it actually surfaces at the 1600 foot level--that's 1600 feet below t he main adit of Bonanza mine.

The green line represents the Jumbo incline. The blue represents the Bonanza incline, a crosscut over to the top of the Mother Lode incline, and the top part of the Mother Lode incline which bottoms out at the 2,800 level.

The orange line is the crosscut between Jumbo and Bonanza at the 600 level. When this tunnel was completed, the power lines that terminated at Bonanza were run underground through that cross-cut. Prior to that, those lines had to run over the top of the ridge and then down to Jumbo, exposing the line to high winds and avalanches. This crosscut also ended at a surface adit on the right side as you see it here.

The purple line was the 800 level cross-cut that extended from a point in the Bonanza incline over to the main adit at the Mother Lode on the other side of the ridge. This was known as the Rhodes tunnel.

Click for a larger image.

 

[blackburn49]

Geology of Kennecott
simplified version
You definitely need to click this map to make sense of it.

What is important here is that we have an underlying level of unknown depth of Nicolai greenstone which is essentially barren of minerals. Above it is the Chitistone limestone.  That is a dolomite which is the host rock for the copper veins which are mostly of chalcocite, chalcopyrite,  malachite and azurite, with the chalcocite being the dominant mineral.  The plane where the two join is known as the contact zone and it is very obvious because of a distinct change in color. The mine adits were all located at the base of this contact zone as you can see from the map. The plane inclines at a roughly thirty-degree angle, which is what determined the angle of the various incline tunnels. Jumbo was 33 degrees. Bonanza was 30 degrees and Mother Lode was 26 degrees.

The large porphyry formation to the south is significant to the occurence of such rich copper veins to the northwest, but is itself largely barren.

 

[blackburn49]

The Rock Glaciers
The previous map showing the geology of the Kennecott area indicates the presence of several rock glaciers. The one most commonly seen is this one behind the Kennecott mill site. When walking up the trail on the way to the Bonanza mine there is a particularly spectacular view of it. These features are approximately forty percent ice with the remainder being crushed rock. They act in the same manner as piedmont glaciers, advancing very slowly, but receding at a much slower pace.
The presence of so many rock glaciers affected mining operations because these features had to be avoided. Thus, many of the tunnels, including the main cross-cut, had to be routed around one of these--the Amazon Glacier. Additionally, the Jumbo and the Mother Lode man camps were built upon these, creating on-going foundation problems.  Click for larger image.

 

[blackburn49]

The Contact Zone
This aerial of the Bonanza Ridge dramatically reveals the contact zone. All mining occurred just above this zone up to a distance of approximately 300 feet from the base, but no farther.  Sometimes the lengths of the veins would exceed 1,000 feet.  The Erie, Jumbo and Bonanza adits and the adjacent surface camps were all placed right on the contact zone.
If you look closely you can see the abandoned Bonanza camp. You can click the above image for a closer view of the landscape, but also take a look below:
This is the detail from that photo showing the buildings perched precariously on the very steep hill. You may also click this image for a wider view.  The photo was taken in 1955.

 

[blackburn49]

The Bonanza Minesite in 2001:
Not much remains these days. Here you see the head of the tram terminal / ore bunke and the remains of the transformer building in the background.  All the rest is gone. It is difficult to tell from this photo, but it is another 1,000 feet from the adit level to the top of Bonanza Peak just above the old mine. (click).

 

[blackburn49]

The NPS Kennecott Drawing:
This rather simplified drawing shows some of the existing buildings at Kennecott in the context of the Nicolai greenstone and the Chitistone limestone. It shows the Bonanza mine at 4,000 feet, but what that actually means is 4,000 feet above Kennecott, which is at the 2,100 foot level for track grade.  Also, Bonanza Ridge tops out at about 7,000 feet, not 6,000 feet.
Click for a larger image

 

[blackburn49]

The Abandoned Bonanza--a Closer View:
Here it was about 1965. So much of it is gone now, but try to imagine what it would have been like to have gone through these buildings back then.  That barrack on the right was probably the largest such building ever built in Alaska at the 6,000 foot level at three stories plus the basement and attic areas. It was designed to house 84 men and seat up to 150 for dinner. (click)

 

[blackburn49]

Bonanza Main Barracks, circa 1918:
I have several photos of this structure. In front is the boiler building. Behind it and slighly up the hill on the right you can see a stack the seems to come out of the ground. It does. That is one of the entrances to the mine.
The other major entry point was behind the ore bunker that you see on the left.  The ore reached this bunker by means of hand-tramming on 30 inch rails. The ore was then dumped into one of two compartments of the ore bin. Below the bunkers were chutes that allowed the ore to enter the aerial tram buckets for the 45 minute ride down the hill. (click).

 

[blackburn49]

Aerial Tram:
This is one of the aerial tram towers, probably near the top of the Bonanza tram line.  Instead of an ore  bucket, what you see is a sling, which was used to transport material up to the mine.

Click for larger image

 

[blackburn49]

Riding the Aerial Tram
Picture shows  an ore bucket as it crosses one of the canyons before reaching the mill.

/> Miners choosing to use this means of travel had to sign an agreement with the company exempting the company from liability. More fatal accidents occurred with this tram than inside the mine itself.

These buckets were moving at five miles per hour. Clearance at the towers was not much. The miner had to be prepared to duck.  

 click either picture  for a larger view

 

[blackburn49]

Early Days: 1907 (?)
Here are two grainy images of the site before the tram was fully operational with the second view looking down in the direction of the tram.  As you can see, the first tram head was very rudimentary.
Those are mining engineers taking samples of the slide area. This was loaded with broken up ore of varying degrees of richness. Much of this slide was eventually scooped up and sent down the tram line.

Even though these images are not that good, you can click onto either of them for a larger size.

 

[blackburn49]

Bonanza Mine Plan, 1911
The tunnel ran through the ridge to the cliff face on the other side. This cliff  is where the high-grade ore was first spotted in 1900. Over time several tunnel openings were developed along the surface of the cliff. 

Click map for larger size