The Great Mine

The “Great Mine” north of the Superstitions was described in the Phoenix Herald and Republican in 1893.  the late Joe Ribaudo discovered the article in the book “Arizona, the Last Frontier”, by Joseph Miller. Here is an excerpt from the newspaper article:

“Over on the north side of this wonderful mountain so peculiar in shape, standing like the ruins of some great walled city with its tall spires and huge monuments, there has been discovered an ancient mining camp. Whether this mining was done by the Indians and Mexicans of the last century, or whether the operations date to years when de Vaca and Black Stephen started from the coast of Florida to find the gold fields toward the setting sun, may never be known. It is certain, however, that there are shafts and tunnels and drifts and stopes and the clearly-defined walls of a great mine. On the dumps are found tons of rock which without doubt came out of these workings.”

The description is of an underground mine, but how can you see the walls of an underground mine? It was surmised that the only thing it could be referring to is “subsidence” or the “cave zone”. The article said the prospectors found the mine in 1888, and they went on to find ore much richer in the Goldfield area. If this large cave zone was seen it 1888, it certain that it is still able to be seen today, even if erosion has taken place?

The greatest challenge during the search for the lost Peralta Mines has been coming terms with just how extensive the mining operations actually were. The cart ruts (on the “Mill Site and Mercury page) told of countless loads of ore going to First Water Canyon, but it didn’t completely “sink in”.  The hinge in the basalt (Cerro Negra) indicated on the Minas del Oro map had to be the key to the location of the underground mining operations.

The Great Mine had to be at Cerro Negra.

While looking at Cerro Negra with Google earth and rotating the view to look south,  the full magnificence of some of  the mining that had taken place was finally seen, and it was breathtaking (see photo below).

This is photo below is looking south towards the Cerro Negra ore body. Much of the center of the uppermost portion of of the deposit has been removed that is nearby the rhyolite, forming a deep subsidence zone; It is guessed that a thickness between 20 to 40 feet was mined. It appears that they focused on the richest supergene ore beneath the drainages. It is known now that the ridges to the east and west of the subsidence zone are elongate silica mounds and the “saddle” between the ridges is a smaller silica mound.

The Subsidence Zone of the Great Mine Looking South

Below is what the rhyolite looks like at the volcanic neck.   This rock is key,  because this comprised the debris that made the strato volcano and was leached by the brine.  It is the source for the massive hematite found on Cerro Negra, the magnetite  for the alteration of the rock inside the caldera, and the magnetite for the 400-500 foot wide zone of highly magnetic granite that surrounds the caldera. It is also the source of much of the GOLD (a .02 opt gold assay was gained from the contact of the porphyry).  There are numerous short dikes of this red Rhyolite on and surrounding Cerro Negra and within the caldera.

Rhyolite Porphyry

There is definite proof of subsidence, and this is on the ridge just north of Cerro Negra (the photo is looking south). This probably appeared long after 1848, after the timber posts and matt rotted and compressed (see the Top Slice method below). These are beds of silicified tuff that are tipped into the subsidence zone; the edges are not eroded (Flatiron is in the background).  Even though a lot of mining took place here, they still barely scratched the surface of the deposit.

West side of Subsidence Zone looking South

The Hoddenplye Map

The Hoddenplye Map below depicts the mine very well, and shows the subsidence zone. This appeared about 1895 (thanks again, Tom Kollenborn).  Note the tiny hole through the top of the mountain, again. This map also shows the “placers” in First Water Canyon that were likely from the reprocessing of sand from earlier operations that did not use mercury  (see the Mill Site and Mercury page).

Hoddenplye Map

The Ortiz Map

At the spot labeled “portal” in the “Subsidence zone of the Great Mine” photo above it was observed that bees were flying out from beneath large rocks beneath a short cliff during the worst of the recent drought. There was green grass there, and they were accessing water. A hole was dug down at the rock face above the bee hole and the brow of a tunnel is believed to have been reached with a shovel; there was a very large stash of saguaro fruit there from pack rats, so there is a significant void.

It is believed that this is the same portal as indicated on the Ortiz Map below of 1884 (thanks again Tom Kollenborn).

Ortiz Map

When the Ortiz map was placed over a google earth photo of the Cerro Negra area using the portal location and the Rhyolite contact as anchors, it can be seen that the miners had tunnels on each end of the subsidence zone, and they explored and mined extensively along the Rhyolite front.  It is believed that some of these tunnels were used to assist in draining water to the portal.  The exact match of the Ortiz map to the topography, portal, and Rhyolite is stunning; this is impossible to be a coincidence. The Ortiz map was not rotated to fit the photo, and it is clearly evident that the tunnel system was surveyed and the map was created using due north.  It is believed that the richest ore in the district came from the area labelled “STOPES”.  This is the contact zone or “skarn” between the Rhyolite stock and the limestone rich upper portion of the Whitetail formation.  This is similar to the ore forming conditions at the famous Little Jonny Mine in Leadville CO.  This was the richest mine in the world for decades.

The overlay above is damning evidence of how the area was extensively mined at relatively shallow depths. The ridge from the portal southward is a elongate silica mound, and the tunnel follows it exactly.

All of the potential cave zones are not shown to prevent the overlay from getting “muddied up”.  The small subsidence zone in the photo is a elongated depression that runs through the center of a silica mound.  The reddish silica in the depression is highly magnetic, and in the photo below (in the rain), the magnet stays in position easily on a vertical face. It appears highly likely that there was a stope beneath this area.
Highly Magnetic Red Basalt

The Burbridge Map

Ironically, the first time the author ever stepped foot in the “subsidence  zone” of Cerro Negra was about 15 years ago.  It was  known than that it was something good because of all the quartz veinlets in the depression, but had no knowledge of IOCG  deposits and silica mounds, and it wasn’t even known that the neck of the volcano was only about 200 feet away.

10 contiguous claims were held at the time, and felt it extremely important to put a claim on this ground, so unknowingly put the center of claim marker #11 right in the middle of the cave zone, creating a claim separate from the rest. That one claim, at the same bearing N20W as the other 10, covered almost the entire Cerro Negra deposit and aligned perfectly with the subsidence zone between two large silica mounds as it is now known.

From almost the time #11 was staked, the author has believed that at least the satellite workings on the right side of the Burbridge map below (thanks again Tom Kollenborn) were at Cerro Negra, but could not “see” the  relationship and alignment before discovering the susidence zone on Google Earth.

It has always been the author’s belief that the Burbridge Map with the translated title, “The Esteemed People of the Salt River District of the North” was a map of an exploration project. The original was dated by the University of Arizona as truly being from the 18th century. Considering the fact that the Spanish drove a tunnel several miles long to drain the mines of Pachuca in the 18th century, this really was “light work” for them.

Burbridge Map

The Burbridge map was overlain on the same google earth photo as the Ortiz photo above (2012 is best). Below is the result:

Burbridge Map overlay

The edge of the Rhyolite, subsidence zone, the saddle (shown below) and other features were used as anchors and the Burbridge Map was not rotated to fit.  Once again, the match was stunning.

The Callejon, or “Straight Pass” also matches perfectly just south of the cave zone and it is known now that this is a smaller silica mound.  The Pass can be seen in the photo below in the caved zone.  The photo does not really do it justice, but it is pretty neat to walk across this saddle in the field, and it’s an easy shortcut.

Although the Burbridge map is not as accurate as the Ortiz, the shafts on the Burbridge map align generally with the tunnels on the Ortiz map, (they deepened them for the lower level).  Applying some mining knowledge, the Burbridge map would be the upper level of the mine, and the Ortiz would be the lower level.

Where the crew of Mandozo Segundo Marzo (shown on the Burbridge Map) drove their tunnels and sunk shafts in 1753 is where the edge of the subsidence zone is today. They simply blocked out the ore for others to follow, and it took almost 100 years to create the subsidence zones that remain on and near Cerro Negra today.

The Top Slicing Mining Method

The only mining method available in the mid-1800’s and earlier for mining thick bulk ore was the top-slicing method. This was the precursor to block-caving, and top-slicing was used at Inspiration and Morenci, Arizona.

Below is a diagram of the old top-slicing mining method.  The Peralta’s would have used a simplified version of this method, with much less tunneling and no raises (vertical openings). If this is indeed a cave zone shown above, this is how they did it. This takes quite a bit of timber, and the Peralta’s did not have much nearby. This must have been the number one limitation regarding the amount of tons they could mine from underground.


Below is a photo of the cave zone next to the saddle area. In the background can be seen El Sombrero at the bearing of S65E. It appears like the rock over the stope is STILL subsiding even today on the sides of the cave zone as the decayed timber mat is crushed below.


A layer of basalt covers the deposit, and jasper, jasperoid, and some gossan has been ejected through the basalt. The ejected material can be found in large quantities today. Because of the abundant limestone cobbles that were beneath the basalt before the IOCG was formed, jasperoid replaced the limestone, and some jasperoid cobbles have been ejected also.

It is believed that the area labeled “STOPES” above was mined by the Stull Stoping method shown below.

Stull Stoping

Below is an illustration of miners mining off of stulls.

The Bicknell Article

To lead into another aspect of the “Great Mine” subject, below is the Bicknell article that was published in January 13, 1895 in the San Francisco Chronicle.


The part of the story that is most unbelievable is where they abandoned the shaft that was being mined by the Mexicans, after they threw the bodies inside, and then they saunter on down the hill and find an outcrop of auriferous quartz.   It is not completely clear though from Bicknell’s writing whether they find a second shaft or not, or start from scratch.

It would seem plausible that if they found a quartz outcrop in say 1868?, and it was fairly large, it would still be there today, unless this happened in Goldfield? How could anything like this escape the eyes of so many for so long and be right out in the open?

The possibility of something like this really exists.

Below is a photo again of the cave zone with the location of a vein and breccia pipe added. This vein has a strike length of over 150’, and its width is about 15 feet wide (really).  There are dozens of other narrower quartz veins in the cave zone, and veinlet swarms.


The breccia pipe is made entirely of the material in the photo below. It is laced with drusy quartz, and copper staining can be seen with a loupe.


These are large quartz crystals covered by chalcedony on the vein that outcrops:


In conclusion, it is very possible that the stories of old could have happened nearly exactly as they were told.

Sims Ely and the Lost Dutchman Mine

Sims Ely wrote the first book about lost mines or “lost mine” in the Superstition Mountains, and he coined the phrase “the lost Dutchman” with the title of his book, the “The Lost Dutchman Mine”. In his lifetime of searching for the mine, he did not find much physical evidence, but he found 40 acres of mesquite stumps near LeBarge Canyon (he spelled it that way) in about the year 1900? He found the diameters and the density of the mesquite remarkable in that the Superstitions were very lacking in trees of this quality. He researched the possibilities, and came to the conclusion that the trees were used in the mine he had been looking for.

Sims was not a mining man, and he wondered what kind of mine would use that many mesquite trees. The square-set mining method, which uses a lot of timber, was not invented until well after 1848, and it needs straight, and much larger timber. This miner offers that the twisted trunks of the mesquite, that are not big enough for timber, were only good for the mining method described above, the top slice method. Their intertwined trunks would have worked fairly well to make the timber mat for the technique.  Sections of the logs would also work well for the Stull Stoping method.

It is not known precisely where the “soldier camp” is that Sims said the stumps were found, but it appears to be about 3 to 4 miles east of the “Great Mine”. It appears that neither the “Great Mine” or the stumps could have existed without the other.

Magnetism as a Pathfinder to mined areas on Cerro Negra

Once the conclusion was drawn that the Prospect was on large IOCG deposit, things began to click. There has to be lots of magnetite for this to be an IOCG. A small, but powerful Neodymium magnet attached to a piece of dental floss was used to conduct a magnetic survey of sorts on the ground.  First, it was learned that all of the soil in Area 1 was loaded with magnetite.  Just by kicking any dirt to loosen it and placing the magnet down brought instant results.  This was emplaced by the fluids emanating from an IOCG deposit below.
Area 1 Magnetic Soil

By testing the basalt around Cerro Negra it was learned that there was a zone of highly magnetite-enriched basalt near its base and near the top.  The next 2 photos show what some of it looks like.  Some of the magnetite-altered basalt is very red inundated with swarms of tiny veinlets of quartz.
Highly Magnetite-Enriched Basalt (glows red under SW UV)

The highly magnetic basalt and veinlets are evidence of a very large epithermal system that is beneath the basalt.

The below rock type is highly magnetic and is a type of silica found on some of the silica mounds. It is extremely tough rock.
Highly Magnetic Basalt

The cave zones surrounding Cerro Negra typically have highly magnetic silica in the bottom of them. Some of the silica is inundated by swarms of quartz veinlets.  Below is a photo of the largest “Great Mine” subsidence zone.  The magnet easily stood on its edge.
Magnetic basalt and veinlets in the Great Mine subsidence zone

There are other subsidence zones on the side of Cerro Negra that closely match the shafts shown on the Burbridge map.   Below is a photo of what is believed to be a pillar on the southwest side of Cerro Negra that “punched” through to the surface. The pillar is non-magnetic.  The rock surrounding it is highly magnetic and chlorite-altered.  This appears to be a waste zone below that was bypassed below and the rock caved around it.
Pillar that has punched through to the surface

Below is a photo from standing on top of the pillar looking southwest which shows the subsidence surrounding it. All of the silica in this subsidence zone is highly magnetic.
SW subsidence

Below is a potential subsidence zone on the northwest side of Cerro Negra.  The rock on the right side of the entrance to this zone is extremely magnetic.
NW Subsidence zone

The Filled-In Shaft

The million dollar question remains: Where is the shaft that Bicknell  described in the article above?  Bicknell interviewed a lot of people and it was unanimous that the mine was accessed by a steeply inclined shaft that was about 80 feet deep.   There is an often-repeated Apache Legend that 40 Apache women and 2 boys left the San Carlos reservation for a “moon” or an entire winter to “hide the mine”.  Stories passed down tell of the 40 Apache women hiding the mine (assuming filling the Bicknell mine shaft) in 1882.  The newspaper article described above told of of the prospectors finding the Great Mine in 1888.

An excellent story about the shaft and Walter and Lydian Perrine is at the link below.  The was written by Jim Hatt, another tireless researcher and great man that has passed.  Sadly, many photos and video links on this site no longer work.

A summary of part of the story is below:

Lydian Perrine, a full-blooded Chiracahua Apache,  was born near the base of El Sombrero(Weavers Needle) in 1860.  She was present when the shaft was filled.  This makes her  22 years old at the time of the shaft filling.  She told her grandson, Walter Perrine (whom she raised) that she was lowered into the shaft before they filled it and that there were two “caves” at the bottom.  In miner-speak, these could have been “stopes”, where the ore was removed.  Lydian could have quite possibly have been the last person to enter a portion of the underground workings of Cerro Negra.
Lydian Perrine (

The ore of IOCG deposits is often very, very tough rock, where openings of great size can be excavated without the fear of collapse.  It is suggested that the “caves” Lydian described are still open today, and can be detected seismically.

One story says the Apache women capped the shaft with a cement made of ground-up caliche.  This sounds far-fetched, but the Apaches did know how to make adobe.

Adobe is very erosion resistant as evidenced by the Casa Grande ruins.   There is a fairly large area covered by the material in the photo below in the location labeled “filled in shaft” in the cave zone photo above.  The shaft would have been needed to be capped with material of this nature because of the steep hillside where the shaft is located. Any fill would be washed away at the shaft collar betraying its location. There was a small hole dug in this material and the photo below is of the side of it.  There is basalt in the bottom of the hole to right in the photo (looking uphill), but it dives steeply to the left.
Adobe at the Filled in Shaft

Note the fragments of rock that are in this material; is a mixture of a variety of rock of all kinds.  There are fragments of tufa (warm spring deposit) in the mixture. There are many tufa mounds throughout the caldera and close to Cerro Negra and they can easily be mistaken for caliche.  So, the story may have legs.
The covered shaft looking uphill

Above is a photo of the adobe area looking uphill.  The small hole dug by the author can be seen.  Recently, there must have been the heaviest rainfall that has fallen in 15 years in the area.  It caused a great amount of erosion everywhere.  By zooming in, it can be seen the veneer of basalt gravel has washed away exposing the adobe.  The adobe area is over 40 feet long uphill-downhill and at least 15 feet wide.  It is surmised that this was the portal for an inclined shaft.

This spot also roughly aligns with the shaft that is solid black on  the Burbridge map.  Maybe the solid coloring on the original means “filled in”? This would have been colored-in over 100 years after the map was created.
The adobe exposed by recent rains
Camouflaged. Looking north at the toe of Cerro Negra. The adobe area is by the Ocotillo.

Above is what the hillside looks like today looking down towards the adobe covered area.  The author has questioned the use of adobe because of its color on basalt,  but the great amount of rain this year has allowed for grass to grow in quantities not seen before.  This is how it must have looked like 130 years ago during the wetter climate, and there must have been a thick layer of brown dead grass to cover and conceal the adobe.

As a final note, below is a drawing that is from the Jim Hatt article. It is somewhat crude, but is shockingly representative of the arrangement at Cerro Negra looking south.  It appears that Lydian told Walter Perrine the location of the mine as the story tells, and he spent a great amount of time looking for it in the early 1960’s, but in the wrong place.