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    Mojave Desert Heritage & Cultural Association

The Gibson Gyratory Crusher Project

The Gibson Gyratory Crusher - Background information and restoration history

06/01/2018  Story by Charlie Connell,  Edited by Debbie Miller Marschke 

Ore crushing machines are typically large and unwieldly. This Gibson Gyratory Crusher was an attempt to make it easier for the miners and mining companies to extract the precious metals from the ore in remote locations. In this case, the design of this particular machine was made to allow the mill to be easily moved to these areas and the geology tested to determine if the location was worthy for full scale mining. There is a Gibson Gyratory Crusher that operates at the Mojave Desert Heritage & Cultural Association in Goffs, California. This is the only one that I know about that operates in the USA.  The following is the information that I have found of the historical account for the Gibson Gyratory Crusher:

Patent Information The Gibson Gyratory Crusher serial # 217,750 was produced by W. W. Gibson and patented on June 22, 1920. I obtained information from the Internet on the United States Patent Office of the patent that discusses the construction of the mill along with pictures of the crusher’s parts. The patent states “The object of the invention is to provide such a mill, which, while substantial and durable in construction, will be very efficient in proportion to its weight, and therefore can easily be transported into inaccessible mining districts, and which can quickly set up.” In other words, it can be used as a test mill. It resembles a large mortar and pestle. The mortar being the round base of the machine that crushes the ore and the pestle being the large shaft that is operated by an eccentric and causes the circular motion that crushes the ore. I do not know of any similar mills produced in that time period. I have only seen one other mill in Jerome, AZ and it was in bad shape. The pictures below are from the patent serial # 217,750.



How the Gyratory Crusher Works  

Mining is an ardous business.  There’s a lot of legwork involved in locating a lucky strike, but that’s when the hard work really begins. All the rock that potentially could contain the precious metals needs to be taken out of the ground and reduced into manageable portions. Quite simply, the next phase is taking the big rocks and turning them into smaller rocks. Miners would typically have on hand some type of jaw crusher or processing equipment to reduce the ore into smaller chunks so it can be processed by a mill. When the rock has been sufficiently reduced to an appropriate size, it is fed through the Gibson Gyratory Crusher which further refines the material into dust or powder. For the Gibson, the material needs to be less than one inch in diameter (that is because as the stem turns, the die only raises up about two inches. The material needs to easily fit into this two inch gap as the die is raised, so that when the stem turns and the die is pivoted, the material is crushed ).  Typically, the ore will be reduced to the one inch chunks by a jaw crushing machine (there are several of these on display at the MDHCA at Goffs). The Gibson Gyratory Crusher works upon the same principles as a hand-held mortar and pestle, just within a much larger scale.  The one inch diameter chuncks of material are fed into the machinery and as the heavy shaft turns in circular “gyrations”, the ore is crushed beneath it. There is a sump (catchment area)  located between the annular die and the launder crusher outlet that is called the "Annular Chamber" that holds mercury. When the crushed material passes over the chamber, the fine gold would be captured by the mercury. The picture below shows the Annular Chamber #89, Annular Shoe #33, Annular Die #53 and the Launder #84, the crusher outlet.



Early Operational History 1930's The Mojave Desert Heritage & Cultural Association has some historical photos of an early Gibson Gyratory Crusher that was located at the Golden Queen Mine area in the Soledad Mountains (Mojave Desert)  in California. The picture below shows a crusher in operation circa 1930’s. The picture has a couple early 30’s vehicles in the background.


As noted in the patent information section, the mill was portable and was taken to remote areas to test for precious ores. The picture below shows the mill setting in a yard, ready to be taken to the field and used to test the area for various ore bearing deposits.



Later History  - “The Move” The crusher was sold to the Mojave Desert Heritage & Cultural Association (MDHCA) in Goffs, CA in 1999. The following bits of information were extracted from the Mojave Road Report Publication of the Friends of the Mojave Road and the Mojave Desert Heritage & Cultural Association, Report number 187, dated January 2000. The report discusses the day by day account of the purchase, disassembly, relocation to Goffs on the 16' Big Tex Trailer and assembly of the crusher at Goffs by Bill Fullerton, a crew of volunteers and with assistance from the folks at the Golden Queen Mine.  This activity was completed in the winter time and the assembly crew braved the wintry weather to get the crusher reassembled into a static display. It was reassembled on the MDHCA property along the “Boulevard of Dreams”.  As with most of the artifacts on display at Goffs, it is a source of pride to have another piece of history conserved for future generations. Potentially, anything can be restored or rehabilitated with the right expertise and perseverance. After our successes restoring the Stotts Stamp Mill and The American Boy Stamp Mill, the project crew started looking for their next challenge.

Restoration Phase It was decided to try to bring the crusher back to operational conditions in 2016. There were a lot of questions about the integrity of the mill, the speed and the device that would drive the crusher since there was not a tech manual for the crusher. This restoration was very simple with only four concerns.

Missing Components We compared the patent drawing to the physical crusher and found three missing items: The cylindrical screen #83 that separates the outlet from the die and launder outlet was missing. This screen ensures that only the fine particles leave the crushing area. This would cut down on the efficiency of the crusher, but we are not running a production mill. Another missing part is the metal wall #86 that prevents any of the pulp from splashing outside the launder. This again is a minor concern since we keep the water flow down so that it does not wash out of the launder. The access port Door #27 is missing. This permits access to parts needing adjustment or oiling. Again, this is not necessary for proper operation of the crusher.  

Mill Structural Integrity We went over the mill and tightened down all the bolting and added some additional timbers to strengthen the mill. We focused on the drive mechanism to ensure the eccentric rotated in a stable manner. We rotated the mill to check the rigidity and found the mill to be solid. The original set up of the crusher was for a static display only.

Driver We know that the component used an electric motor as identified in the first picture above and the patent says that the speed of the drive shaft to the pinion gear would be about 200 RPM. We did some calculations and found the required speed of the mill at about 52 RPM. We ended up using a fractional Hp motor and a double belt drive. The motor was mounted on a hinge device that used the weight of the motor to obtain the proper tension on the belt drive. The motor had plenty of power to run the mill.

Gold Recovery Next, we had to set up a device that could catch the concentrates. We constructed a standard sluice table with miners’ moss and riffles to catch the gold in the crusher ore. We installed a pump in a trough and recirculated the water. 

Mill Operation Phase After over 80 years we ran the mill with water and crushed our first ore on Saturday, April 22, 2017. By the way this is the only Gibson Gyratory Crusher, to my knowledge, that operates in the USA. I have only seen one other gyratory crusher in the USA and it was in pieces at the Gold King mine in Jerome, AZ. The initial run of the gyratory crusher was during the MDHCA  "volunteer working weekend" event (the organization calls it "Encampment", which occurs each April, annually)  with about 25 observers present. Everyone was impressed with the accomplishment.

Volunteer Crew 1, December 1999 : Leader: Bill Fullerton. Crew: Charles Hughes, Ed Ditmer, Dave Given, Doug Given, Ray Kath, Patrick Lewis. They moved the artifact from The Golden Queen to Goffs, and reassembled it for static display.

Volunteer Crew 2, 2017: Leader Charlie Connell. Crew: Roger Camplin, Dale McBride, Nance Fite, Phil Motz, Stuart Harrah, Paul Haueisen, Chuck Messersmith, Gail Andress, Rick Nesbit, and Don Cleland. This group placed the crusher back in operation over the course of one year's time.