(16) 1915 Mine Productivity Determination

I conducted an historical review on a small local Gold Mine and during the research I found an actual evaluation of the production of the mine completed in April 1915 by a local geologist. I have developed two slides that show the production values of the mine.

The first table below discussed the Mine Assay Values. Four samples were taken from various locations in the mine and assayed for gold and copper, the prevalent ores in the mine. Each sample was analyzed and they came up with a dollar value per ton. Today we use ounces of the ore instead of dollar value since metal prices fluctuate quite a bit. As noted on the table the 1915 gold and copper values were $21 per ounce for gold and $0.08 a pound for copper. I made up a second column for the gold and copper prices in 2012 with gold being at about $1,700 per ounce and copper being approximately $3.55 per pound. You can see that the average per ton was $27 and at today’s prices it would be $1,500 per ton. The results were that the mine had some good ore values.

He went on to determine if the mine operation could continue on the ore values that were found. This is where the second table below for Mine Production was used. This takes into consideration all of the individual operating costs. It is interesting to see how much each component would cost in 1915. To find out what the comparable prices would be today I used the Consumer Price Index (CPI) for today as compared to 1915. The factor was $1 in 1915 which would be worth $23 today. I developed a second column and used the price of each item times 23 to get the cost today.  The engineer totaled each of the individual cost of mine operations. Once he had those figures the mining mechanism, a 10-stamp mill, was factored in to determine how much ore could be processed. It was determined that the mill could process 30 tons per day. The profit was determined by subtracting the mine operating cost per ton from the mine production per ton and multiplying that number by 30. The geologist determined that the values obtained were adequate for the mine to stay in business. The actual operating cost today will be more, in that, there are other costs that are included such as reclamation costs that were not in place in 1915 and would make the final cost of operations much more and the total profit less.  

       

(15) American Boy 10-Stamp Mill Progress

I have been involved with the restoration of this 10-stamp Mill at the Mojave Desert Heritage & Cultural Association in Goffs, California. The restoration was started about three years ago and is proceeding well.

We last worked on the American Boy stamp mill on the weekend of April 11 through April 14:  There were (9) volunteers that participated in the significant progress made that weekend. The following work was completed:

Transition Deck Installation The purpose of the transition deck is to allow operators to access the upper ore bin deck from the back of the mill and walk around to the operator’s deck. This keeps the front of the stamp mill visible and eliminates the need for a pair of stairs in front of the mill. The picture below shows the transition deck being installed: 

Railing and Kick Plate Installation Railing had to be installed to keep the operators from falling off the deck and keeping them clear of the rotating equipment. The 6” kick plates along the base of the walkway keep tools and other items from falling on personnel under the deck. 

Installation of the Staircase The staircase was donated by the Superstition Mountain Museum, Apache Junction, Arizona. The staircase had to be modified to overlap the deck and assure that the staircase would be securely anchored to the upper deck. There was also a platform constructed to set the bottom of the staircase. The platform is not shown in this picture. 

Finished Transition Deck and Access Staircase The deck assembly went off with great success. The deck allows access to the operator’s section and protects the operators. 

Jackshaft Stiffener Installation The jackshaft moved slightly when running the mill, so railroad ties were used with concrete anchors to stiffen the jackshaft. The modification was a great success making the jackshaft “rock steady” during mill operation.  

Detroit Diesel engine The engine pulley was changed to a smaller pulley to allow the engine to run at its optimum speed (approximately 2000 RPM) and have the speed of the bull wheel at about 60 RPM. When the engine was run it sounded much better and will significantly improve the life of the engine. The engine was moved further away from the deck to allow better utilization of the engine adjustment. The engine was run twice and the bull wheels engaged. The belts tracked well and the overall operation is ready to start dropping shoes after the idler pulleys are installed. 

A presentation was made after the Saturday Evening Dinner. FedEx Express in Irvine, California donated drive belts for the American Boy Stamp mill. They also donated belts to two other museums. The picture below shows the collage of pictures of the Goffs American Boy 10-stamp mill, Cave Creek’s Golden Reef 10-stamp mill and Superstition Mountain Museum’s Cossak 20-Stamp Mill. In the picture from left to right we have Roger Camplin representing Superstition Mountain Museum, Nance Fite representing FedEx, and the recipient of the collage, Hugh Brown the Executive Director of the Mojave Desert Heritage & Cultural Association and finally Charlie Connell (author of stampmillman) representing Cave Creek Museum. 

The following are some additional pictures of the status of the mill in late April 2013. We are expecting the mill to be operational by September 2013.





(14) Upcoming Mining Artifact Shows & Events

UPCOMING MINING ARTIFACT SHOWS & EVENTS

2014 (UPDATE 6/2014)

I have listed a grouping of specialized mining artifact shows that are selling nothing but mining artifacts. There are not many of these shows in the US, but I have been to the one in Tucson, Arizona and one in Grass Valley, California. Both shows had some extremely nice items, both small and large such as small blasting cap boxes to ore carts and other large components. There have actually been entire stamp mills for sale at these shows. If you have never been to this type of show, I think you will find it interesting if you like old mining artifacts.

There is currently only one show in the Nevada City area that is rich in mining history and while you are there you should visit the North Star Mining Museum in Grass Valley and also the Kentucky Mine tour in Sierra City, California. They both have stamp mills that are in excellent shape.  

2013 Mining Antique Collectors Swap Meet and Auction

Date:                Saturday, June 28, 2014

Location:          Nevada City Elks Bldg, 518 Highway 49, Nevada City, CA

Swap Meet:      9 AM – 4 PM, open to the public at 10 AM, Set up 8 AM

Social:              4:30 – 6 No host bar at Elks

Dinner: 6 PM  $30 per person

Auction:            Immediately following the dinner

Further information?  dwkfargo@aol.com

(13) Constructing A Mining Ore Skip Cart

Constructing A Mining Ore Skip Cart

Mining ore cart skips were used on shafts that were incline. The incline could be anywhere from a 30 degree angle to greater than an 80 degree angle. The skips were constructed differently than the regular back dump and side dump carts that you are use to seeing. They were open on one end and could have the top partially covered. They would bring the ore up to the surface and then dump the material in an ore bin. The picture below shows an incline shaft cart in operation.

There are many different sizes and shapes of incline skips, but they all have a front end open with some coverage on the top of the cart.

I designed an incline skip to be used with certain size restrictions and the drawing below shows the basic size of the sheet steel parts for the construction of the box.

The drawing below shows the construction of the skip, including the overall dimensions for the skip.

The side view of the skip shows the bail. This device is tied to the back of the winch and controls movement of the cart. It is made from approximately 16 feet of 2" X 1/4" strap steel listed on the additional parts list. The 3 views of the completed skip towards the end of the lesson gives you a better perspective of the additional minor materials to construct the cart. You need to find (4) approximately 8" wheels and (2) 16" axels to fit the wheels to complete the parts for the skip.  

The pieces of the skip were made from 1/8” steel plate. There were over 100 cold rivets used to assemble the skip with no welding involved. This is patterned after skips made in the 1800’s. The more recent skips do not use rivets and are welded together.

I have some pictures of the skip during construction below that show how the skip was assembled. You have to be careful assembling the skip so that you can hammer the rivets without problems with clearance. You will need about 15' of 1 1/2" light wall angle iron to assemble the skip.  The first step was to install the angle iron and rivets on the back side of the box as shown below:

You will need about 6' of 1 1/2" flat steel to complete the front sides of the cart. The next step was to install the sides of the skip:

Once the side was riveted together I installed the bottom plate and installed the rivets on the final side of the box.

The picture below shows three views of the skip box completed. I had to install the small top cover and it was assembled with carriage bolts so that the top could be removed for maintenance. The last steel to be placed on the box was the bail. This allows you to pull the skip up from the mine and gives you flexibility to dump the skip.

Once the skip box assembly was completed we installed the wheels and axels on the bottom of the skip. The picture shows the assembled skip on an incline. The incline is still being constructed in this picture as well as the placing of the crusher over the skip.

(12) Restoring a Gardner Denver Mining Mucker

RESTORING A GARDENER DENVER MINING MUCKER

What is a mucker?

Muckers were used underground to remove rock and ore known as “Muck” after blasting in the tunnels. They were used from the 1930’s through the 1960’s and still in some small operating mines. The mucker weighs 4,300 pounds and operates on 60 to 100 pound air, no more than medium sized drifters. There are two air motors that run the mucker, a drive motor and dipper motor. The drive motor is located under the base and drives the four wheels to move the mucker back and forth. The dipper motor operates the shovel on the front of the mucker. It picks up the muck and flings it over the machine to an ore cart that is attached to the mucker. When the ore cart is filled, it is detached and taken to the surface and dumped.   The drawing below shows a side view of the mucker with the air motors.

The picture below shows a GD-9 mucker in operation on the cover of a tech manual for the mucker. You can see the ore cart behind the mucker. The dipper is full and ready to fling the material over the Muckers into the ore cart. 

Where did this Mucker come From?

The Gardener Denver GD-9 mucker that we restored was used in the Red Rover Mine in Seven Springs, Arizona. The Red Rover Mine was established around 1882 and was the most successful mining operation in the Cave Creek Mining District.  Copper carbonates, that contained as much as 2000 oz. of silver per ton, were found at the surface of the deposit. Major production at the mine occurred from 1882 to 1917 during which $200,000 in copper and silver was recovered, but between 1917 and 1953, it had been operated intermittently.

The mine was purchased by the Tozier Family in the early 1960’s. By the late 1960s they had found the money to do some under-ground mining.  A new drift/tunnel was dug into the hill under an old building which had been the Cook Shack. As the drift was dug, water and air was piped in and track was put down for the ore car and mucker.   Two family members ran the operation.  They would drill and shoot the rock face and then move the waste outside with the mucker and ore car.  They always moved carefully when the mucker was running.  The heavy steel shovel would jerk up and back to load the ore car.  It could have easily broken an arm or someone’s head if one got in the way. We visited the mine to see about some timbers to be used on a stamp mill restoration and that is when the two Muckers and ore cart were obtained.

How Did We get it from the Mine?

The mucker was acquired in March of 1996 from the Tozier family at the Red Rover Mine. The mine is located off the Seven Springs road, about 5 miles south of the springs. The access road is located on a dirt road that is about 2 miles long. About half of the road is actually a dry wash with large rocks that are shifted around when the rains hit. It is not your ideal road to bring the 4,300 pound mucker out in the back of a pickup truck. We did have about 15 volunteers to help in getting the mucker and some other items that had been acquired from the Toziers. We had no jacks or other devices to raise the mucker off the ground. Everything was done with levers and cribbing timbers. The pictures below show the various stages of the transfer of the mucker into the truck bed:

We moved the mucker out to a location near the truck.

We jacked the mucker off the ground about 3 feet with nothing but levers, cribbing timbers and brute strength.

We dug holes to back the truck into and then rolled the mucker onto the truck bed.

Restoration of the Mucker

The mucker was totally restored back to operation. This was done in several steps over a couple years.

The first thing that was done was to check out the air motors and make sure they are still operable. There was still oil in the air motor sumps. This meant that the basic machine will run. The air motor shift valves were removed and it was found they were in good condition.

The next part of the restoration is as follows; degrease, sandblast, prime and put the original color paint on the machine. The machine had to be degreased, since the oil that is in the air motors ends up all over the frame. This is due to the air that goes into the air motors and has oil in it to keep the parts lubricated during operation. Years of use builds up a thick coating of oil and dirt that had to be removed from the entire frame. Once that was done the entire machine was primed with grey bridge primer, a very resistant sealer to oil and grease. The final top coat of paint of Gardner Denver Green was put on the entire machine.

Next we had to work on the linkages, air lines, shifting valves and the motor control lever that was frozen, and also dipper chains that was totally stiff from rust and contained years of grease and dirt. It took a week of soaking to clean the drive chains. We also had to remove the drive motor controller and soak it with Kroil to break it loose. The last thing we worked on was the removal of the shift valve and then cleaned it out. All of the parts were reassembled and the mucker was ready to go. We spent about 2 months working on the moving parts on the mucker to get it running correctly.

Mucker Operation

The restoration took several years between the acquisition, sandblasting, painting, fine tuning and operation. The picture below shows the engineers checking out the machine.

The pictures below show the mucker in operation.

(11) Stamp Mill Forging Companies

I have noticed that there are many foundry companies, some large and some small, that manufactured stamp mill mortar boxes and other stamp mill components. I also noted that they are located in several locations. After conducting a review of stamp mill foundries that have been in business over the years, I have found (28) companies located in California, Nevada, Colorado, Illinois, Alaska, Arizona, North Carolina, and even in Canada. I discovered a total of 46 mills during the search.

Several stamp mills did not have any name or identification on the mortar boxes or major components. This represents about 25% of the mills that I researched. I did place one of the mills on the listing that I have not learned the foundry it came from as of this project completion. I have identified the mills that are “operable”. This means that they can rotate the mill. The mill at the Kentucky Mine is rotated by the tour guide grabbing onto the drive belt and pulling it until the one stamp that is engaged, is lifted up and then drops. On the other hand the stamp mill at the Arizona Mining & Mineral Museum operates at 60 RPM, has a feeder that works, and the resulting ore is processed though a gold wheel.  

I have visibly verified all but two of the locations. They are in Georgia and North Carolina and I have not had the chance to go to those locations for first hand validation and video taping. Both of those mills do operate.

This is by no means a total list, since I know that it has not been possible for me to travel to every part of the US and Canada. I have spent some time investigating Australia and Tasmania, and there are stamp mills in both areas. This is for another project.

I assembled a listing of public stamp mills that are being operated at the end of the slides for your information. This will allow you to gather more information and maybe visit the museums listed.

If there is any information that is not correct, please contact me by writing a comment in my Blog.

The following slides are in alphabetical oder by foundry. Enjoy!