The American Mine, Yellowstone District, Cochise County, Arizona
By Rolf Luetcke
The story of my personal experience with the American Mine in SE Arizona began only about 5 or 6 years ago. I had heard of this mine on a few occasions but had never actually been there.
My wife Mary and I were exploring some of the mines in our vicinity when we came across the mine on mindat. It was not too far away and we decided to see if we could find it.
Turns out it is 25 miles from our house to the mine. When we drove the paved road from Benson Arizona up the San Pedro River valley through the small town of Pomerene we had been this road many times. When we got to Three Links Road we had also driven this road, which is a dirt road that crosses the open country of the valley and ends up going East past the Winchester Mountains and on to Willcox. During wildflower blooms after a wet winter the plains off of the Three Links Road are full of flowers. Since it has been nearly a 20 year drought it has not been good for flowers in many years.
We found the small dirt road we had found on the topographic map that led to the American Mine and it was about a mile from the main dirt road to the old mine.
Historically, the American Mine was discovered in about 1880 and worked off and on several times. The mines depth went to about 100 feet and the dumps are somewhat spread out. The estimates of ore removed from the mine was about 125 tons. The literature on the mine states it was flooded in the 1960's and has water at the bottom. There is a big cattle water tank right near the mine and that is the end of the side road.
We parked next to the one open shaft to the mine. There is a little rise to the mine shaft but it is not fenced and a fall could happen quite easily since the surrounding dirt is loose. Care is advised here if you plan to visit the mine.
The thing we noticed right away was the heavy black crystals of the main mineral lying on the old dumps of specularite, a variety of hematite. There was also quite a bit of blue from chrysocolla.
We collected a number of pieces to take home to study on our first trip to the mine.
We also noticed that about a quarter mile South of the actual mine was another small pit. We stopped at this pit as well and the ore was exactly the same as at the actual mine. In line from this pit to the mine we could see numerous scrapings where the same vein had been followed and a bit of exploration had been done. The ore veins with hematite here trended basically South to North.
The granite of the area was intruded by quartz and the ores are heavy with hematite. The mine had been mined for lead, copper, silver, gold, fluorspar and baryte.
Out of all the material we took home to study we found a number of minerals but never did see the fluorite they had been after to some degree or the lead and silver mineralization.
When I first looked at the mindat page I saw one photo of a mineral from there, geyserite. I had not heard of it and looked it up. They said it was associated with intrusive hot waters or gasses and was a variety of opal. This didn't seem to fit for me and I didn't see anything that looked like this piece on the dumps.
When I read the description of the geology of the mine I read about the jasperoid body that had been the control for the ore veins. We had never seen any of the jasper material in the first few times we visited the mine.
When I broke up the material to examine after the first trip I found one of the hematite pieces that had a number of holes with lustrous crystals that sparkled in the sunshine. When I took the piece to the microscope I saw it was clusters of baryte crystals that were sparkling. Along with the baryte was also quartz, water clear and in some places with a frosting over much of the tops of the crystals. I found one piece that had these nice baryte crystals. No other pieces with the baryte crystals have been found by us since.
Most of the hematite was in massive form called specularite but occasionally there were free standing hematite crystals. One find had a pocket of free standing black hematite crystals on colorless quartz crystals. When the light hit the hematite crystals from behind you could see the deep red color showing through the crystals.
On a recent trip with a friend to look for possible gold we picked up chunks that looked a bit different. When I got home the one light colored chunk I had brought home was much lighter in weight than the normal black to dark brown hematite ore. When I broke up this piece and looked under the microscope I saw it was part of the granodiorite stock that had been in the area. Since there was a bit of copper color as well I studied the piece. On examination I found about 8 minerals in the material. A pink feldspar, colorless quartz, white to light greenish mica variety sericite, red to black hematite and some tiny tetragonal black crystals. When I broke off a few of the tetragonal crystals they were strongly magnetic and showed they were magnetite. The magnetite crystals were tiny and not very well formed and most seemed to form in clusters or what I started calling pods. Near the black magnetite clusters were some other pods of a brown mineral. These pods were very small and were hard to find identifiable crystals. As I looked at all the pieces I came across the tiny bipyramidal crystals that were lustrous, striated, translucent and my first thought was anatase. I had never found anatase in our area before and I looked in my Mineralogy of Arizona book and it was not listed for Cochise County. On mindat it was shown to be here at several locations in our county.
Since I only had one piece of the lighter material we took another trip out. I fortunately remembered where Mary had picked it up. There was more of the material and we brought some home. On looking around Mary found two pink, fist sized pieces she also had me take along. They were the only pieces of this pink material she had seen on the dumps.
When we got home I found the light colored material was the right material and it also had anatase in it. Unfortunately no larger crystals were found.
When looking at the two pink pieces Mary had picked up two things fell into place. I saw under magnification that it was the jasper material they had mentioned in the mine description. When I broke the one piece I also found something I had not found before. There was the geyserite that I had first seen on the mindat page. The geyserite I found was how I had envisioned the material to have formed. It had formed either from hot intruding waters or gasses and the opal deposited in coarse, minute splinters and at a later time the colorless, botryoidal opal had deposited as well. It fit the description of geyserite perfectly. The jasper also fit and at places was one pink color of massive material and on the edges had incorporated tiny fragments of other material in the jasper. Not much of this material seems to have come up from underground because it had not contained any of the mineralization they had been after.
It was no wonder I had not picked it up before, it was not associated with the hematite ore from the mine but a completely different rock type. I had overlooked the pink material on previous trips.
This made several things fall into place and the description of the geology was finally complete in my mind.
Some of the minerals they had listed for the mine I have not found. Lead minerals seem not to be in the dumps, at least we have not found any. The same goes for the silver mineralization, none has been found so far by us. Copper and iron were easily found, as was some baryte but fluorite has not been found by us either.
We have found about 20 different minerals and varieties at the mine, which at first looked like it would not have nearly as many minerals to be found. Most of the minerals were micro minerals but the iron and copper colors were still to be found in larger pieces which were mostly decorative and not of specimens quality.
We have not found any pyrite that has not been completely replaced by iron. Some of the other minerals listed on the mindat page have also been missing on the dumps. The dumps still have color and for visitors there is a good amount of material still lying on the ground.
I found it interesting how many times one has to visit a certain locality to fit all the pieces of the deposit into place. The American Mine was no exception but it has produced some nice micromount material for our collection.