Bonanza Gold

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cuzzinjack
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Bonanza Gold

Post by cuzzinjack »

Hello,

During my mining career, I have always been fascinated by Bonanza gold ore, how the wonderful rock was formed, and how and where it has occurred.
The richest gold mine in the world for decades was the Little Jonny Mine (or Ibex) in Leadville, Colorado (about 1893 to the 1930’s). The Superintendent of the mine was the husband of the “Unsinkable Molly Brown”. Below is a photo of the mine at timberline (12,000 feet):

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Below is a write-up about the mine:

“During Campion's days, miners found the 'golden stairs' and ‘millionaire's chamber on the third level between Numbers 1 and 2 shafts of the Ibex (Number 1 was the Little Jonny). The stairs – a step fault – had wire and sheet gold; the chamber - a cave – was similarly inlaid. “It (the gold) could be pried off with a chisel or screwdriver,' said one observer” (Gilfillan, 1964).
Emmons (1927) describes another find as follows: "Wire and leaf gold occurred very abundantly in a seam of sulfide which was found on the sixth level of the Ibex about 200 feet south of the Big Four shaft and which was associated with certain highly siliceous ores interbedded with black ‘Weber shales.' Some of the richest ore found in the Ibex mine was taken from this locality. The oxidized siliceous ore in one of the stopes above the third level of the same mine contained a small but remarkably rich seam of leaf and wire gold mingled with decomposed silicified porphyry. Sixteen sacks mined from this seam carried more than 50 percent of gold. In a specimen from this locality, seen in the office of the Ibex Mining Co., the gold occurs in a seam of compact jasperoid between limestone and porphyry. The jasperoid is stained deep brown by iron, has a conchoidal fracture, and contains sheets of gold in the joints. Some of these sheets are from 1 to 2 inches across. The gold is pure yellow and 860 fine. Another specimen in the company's office, from the sixth level of the Ibex mine, shows a large cluster of zinc blende and pyrite crystals which form a coating half an inch thick on a quartz seam. The quartz, partly stained by oxidation, shows many irregular openings which contain free gold, mostly in long wires but partly in leaf-like plates.”

Sound familiar? A similar cave was found at the Cresson Mine in Cripple Creek. Below is a piece of gold ore from the Little Jonny (24 ounces)

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I worked at the Black Cloud Mine for over 8 years, which was about 1 mile away from the Little Jonny. A retired miner I knew was raised in Jonnytown near the mine, and he said as a boy he saw 2 miners carrying what looked like a cabbage head of gold in a dynamite box to the mine office to get locked up in the safe. The Black Cloud was a lead-zinc-silver-gold mine without the bonanza gold, but one time a contracted driller cored through a half inch vein of pure gold, and he gave the core to the General Manager. The GM split the core and gave the driller half of it for his honesty. It was a beautiful specimen.

One evening after work at “The Cloud”, I was informed that a woman named Mary Ann Sadar (80 years old) had 2-5 gallon buckets of concentrate she wanted someone to look at. I was told that her late husband was the mill superintendent at the Little Jonny. I was very interested. She gave a friend of mine and myself two buckets of jig concentrates (sand), two small full jars which she said were silver nuggets and a another jar which had 3 golf ball sized chunks of what she called “silver amalgam”. We agreed to split any proceeds 50/50. To make a long story short, we processed the material into small bars, it was almost all gold (25 ounces), and we gave her a check for 5,000 dollars. It kind of took her breath away. It was kind of cool being loosely associated with the Titanic thread.

So how about the Peralta Mines? It is known where they were located, and an IOCG (Iron Oxide Copper Gold) deposit is located there, but the paradox is that IOCG deposits are not known for bonanza gold, and the Peralta’s had to be mining the type of stupid-rich ore that is described above. What was the mechanism that made the ore they mined so rich if it can’t be an IOCG type deposit?

Finally, there was a break in the case. There is a conical shaped hill on the north side of the Molly Marie Prospect that I have pored over for years off and on. I thought it was just silicified basalt, and finally I had an epiphany………. the hill was a sub-sea hydrothermal silica-hematite mound (vent) composed almost entirely of silica (quartz). There was another large one right next to it. I knew that there was a vent in the area because of the abundant banded jasper (jaspillite) found, but I guess the reason it took so long to figure it out is because I just couldn’t accept the fact that something so large, rare, and important could be undiscovered. This is what the hill looks like from the Needle Overlook parking lot (it’s the hill on the left).

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A light came on, and armed with this concept, I decided to look at all the basalt on the property, very carefully. Lo and behold, about half of the mapped “basalt” on the claims is not basalt at all, but basalt covered with hydrothermal mounds of silica (quartz) rich in hematite. There in an entire FIELD of hydrothermal silica mounds! This in itself was not a shocker considering the IOCG deposit formed under a brine lake and there was a great amount of hydrothermal activity. The shocker is that I had walked over the basalt literally thousands of times and it hadn’t clicked! I have not been able to find even one instance of an IOCG that has been found in the world that is this complete, with the silica mounds, but it seems logical that all IOCG’s would have them before erosion takes place. This a photo of one of the smaller mounds that has been partially eroded.

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This is a photo of a piece of the silica that has been sawn:

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In defense of myself and the oodles of prospectors that have crossed the area, there is strange phenomenon regarding these silica mounds that must have caused others to miss this also for over 130 years. First, a piece of the silica must be crushed to powder with a mortar and pestle or other device; prospectors used to do this in lieu of fire assaying. Some of the crushed silica is a light gray and some is pink because of the hematite. Most of the silica is very brittle. I use a piece of window screen to separate the larger material when I use a mortar to make sure all of the rock is pulverized. Then, the sand must be rinsed in the pan until the gray or pink cloudiness is gone. Don’t let any of the sand out of the pan. Now drain just the water out of the pan. What remains looks like an entire pan of black sand. Now, try a magnet on it. It isn’t magnetic! (there is a little magnetite at the bottom). I think that is where the old timers quit. They thought, “hell, this is just basalt”, and threw the stuff away. Not so fast. under a 20x loupe, it is revealed that the sand is pure clear silica (quartz), but each grain is at least partially coated with black manganese. Much of the manganese has been knocked off, but the quartz grains are clear, and the manganese behind is projected through the un-magnified clear grains making it all of it look very black!

Below is a pan of the black material:

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This is what the sand looks like up close:

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I remembered that I had sampled two of the mounds (even though I didn’t know what they were at the time) and went back through some old records and found the fire assays from Jacobs Assaying in Tucson from about 15 years ago and a map that was made to show their location. They assayed significant gold, but not bonanza gold of course. The bonanza gold is at the base of the larger mounds, concentrated and deposited by supergene enrichment. It is extremely ironic that 3 of the samples that ran significant gold were located on the mound where the Ortiz tunnel terminates to the west where there is an obvious subsidence zone through the center of the mound that appears to be located on the feeder structure for the mound. The small oval on the western side is the subsidence zone.

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There are more photos of the silica, etc. on the opening page of my website:

https://mollymarieprospect.com/

And, the conclusion page has been greatly expanded summarize the work that has been done and the discoveries that have been made over the past 20 years:

https://mollymarieprospect.com/blog/conclusion/

cuzzinjack
cuzzinjack
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Re: Bonanza Gold

Post by cuzzinjack »

Hello again,

Below is a photo of the hill that can be seen from the sidewalk, looking south.

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A photo of the silica beds on the hill is below. This photo in itself is pretty damning evidence of what the hill is: a giant silica/hematite mound.

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This hill is very similar to a VMS deposit except there is a lot of iron oxide instead of pyrite. The kicker is, there is an entire mound FIELD on the Molly Marie prospect, and a great IOCG deposit lies beneath them.

Below is a diagram of an idealized VMS deposit.

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The richest gold mine in the world from 1994 to 2008 was the Eskay Creek mine in British Columbia. It was a VMS deposit, a type of deposit which typically does not have high grade gold, and it was concluded that the reason it was so rich is because it formed under shallow water (like the Molly Marie Prospect deposits did). They have been looking for another one ever since.

I think this Prospect will soon be the richest gold mine in the world.

cuzzinjack
cuzzinjack
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Re: Bonanza Gold

Post by cuzzinjack »

To continue with this thread,

The photo below is of the banded jasper that was deposited and is found outcropping to the west and southwest of the hill (mound) that is described above (the hill is in the upper left of the photo).

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This striking banded jasper is found surrounding undersea vms and silica mounds as shown in the diagram below. It is called the “exhalite horizon”. This is similar to the diagram above, but from another geologist’s perspective.

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Why is this important regarding the Peralta Mines? Because on the southern half of the hydrothermal silica mound field the BANDED JASPER HAS BEEN REMOVED.

Cerro Negra, the largest mound of all, and site of the “Great Mine”, has none of the japser surrounding it, and it should be able to be found there in great quantities; there have been a few pieces found though.

There is great evidence that the mines were hidden, and it can be proven geologically.

On a related subject………….. about 7 years ago, a mercury vapor detector was rented to prove the cart ruts in solid rock and that the ore from the district was processed in First Water Canyon. The details of the investigation were posted on this site.
On the last day of the rental, a cursory inspection was made on the south side of the Molly Marie caldera. The alarm on the detector was sounding off in the open air frequently while on the “basalt”. I was wandering around aimlessly on the basalt trying to figure out the source of the mercury. I thought it was from ore processing and posted the theory, again on this site.

It is known now that I was walking on and amongst hydrothermal silica mounds, which typically contain significant mercury.

cuzzinjack
cuzzinjack
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Re: Bonanza Gold

Post by cuzzinjack »

Hello,

Over the past month there has been a lot of searching, researching, soul-searching, second guessing, and total disbelief. How could something this big have escaped so many for so long (yours truly included)?

Here is a google earth photo of the mounds that have been identified. It is estimated that about 80% are shown here:

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This is where one of the mounds was cut by gully/wash/arroyo. This is almost solid quartz.

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This is what some select pieces of silica look like. This photo is high resolution and zooming will show the abundant iron oxide and the green apatite.

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Finally, a near surface deposit has been found to match the legend; a type that has not been found before (as far as can be found so far).

Below is Cerro Negra area with the Ortiz map placed on top. This Spanish/Mexican map has been found to be the most accurate, surveyed to true north.
It is clear that the Peralta’s were targeting the mounds, and some were more valuable than others.

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cuzzinjack
cuzzinjack
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Re: Bonanza Gold

Post by cuzzinjack »

Hello,

About a month ago I was speaking with an experienced Arizona mining man, and he told me it was commonplace for the small miner to use a bathtub to precipitate copper from the weak sulfuric acid used to leach copper from crushed rock containing chrysocolla. The porcelain coated tub (resistant to acid) was filled with shredded steel cans, and the pregnant copper solution was added. The copper replaced the steel in the tub and copper was left behind.
When he told me this, a light came on, and I remembered a bathtub that is in the silica mound area. I have long wondered why someone would go to the trouble of bringing this out to the desert. Below is a photo of it.

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It is guesstimated that this was brought out here in the 1960’s. There are random pieces of chrysocolla scattered throughout the mounds, and prospectors realized the copper potential. There are three places in the area of the mounds where it can be seen that mining barely got started and it was stopped. A vertical 3” diameter drill hole is found not too far from the bathtub. It appears to have been drilled with an air track drill as a blasthole, but was never blasted. There are likely more holes in that vicinity. In another area, one blast was done, the rock was removed, and a large area was cleared to bare rock to drill more blastholes, but the drilling was never done. There is significant chrysocolla found there. On another mound, a large blast was done, but the rock was never removed. There is also significant chrysocolla in that area. At Cerro Negra, a shaft with a concrete collar was sunk only 20 feet (although someone could have been killed there).

What is odd is that in all of these locations, the prospectors barely got started; they did not far enough along to experience success or failure. Why did they all stop so soon?

cuzzinjack
cuzzinjack
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Re: Bonanza Gold

Post by cuzzinjack »

Hello again,

On my wall I have a mining claim map of Leadville, Colorado from 1901. A photo of a portion of it is below.

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Below is a zoomed in portion of the area of discussion. The Little Jonny, the Black Cloud, the Irene, and the Yak tunnel have arrows calling them out. The curved lines on and near the Little Jonny are narrow gauge rail on the surface; the rail was servicing the richest mine in the world!

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Our secondary escape shaft was the Irene shaft and it wasn’t very far from the Little Jonny. We mined the orebodies between the Black Cloud and the Irene claims, and they each had a shaft on them by the same name. My initiation as a young engineer was to “break trail” in the Yak Tunnel from near the Irene to the portal 3 miles downstream. The iron hydroxide (from decomposition of pyrite) was knee deep, and the leader had to break trail in this orange slime for others to follow. You carried a pole to balance off the walls of the tunnel, and had to feel for the rail with your feet. The drainage ditch was very deep along the side and you didn’t want to fall in!

The Little Jonny ore occurred next to Breece Hill, which was a stock of porphyry. Very similarly, the Peralta’s targeted the zone next to the Rhyolite porphyry in the diagram below. I believe that is where they mined the richest ore. The upper Whitetail formation has a high percentage of limestone cobbles and some cobbles can be found on the surface where they have been replaced by the rock jasperoid; this is described similarly for the Little Jonny above.

Stopes are where ore is mined. The logs from the “stumped out” area described by Sims Ely would have had a great use here. The logs would be used as “stulls”, and are installed from wall to wall in a narrow vertical open stope to have something to stand on when mining upwards. The amount of ore they left behind must be incredible.

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In the bigger picture however, the IOCG mound field is over one mile long and including the breccias, is almost a half mile wide. At 1000’ thick The IOCG ore could be a BILLION tons in size.

cuzzinjack
cuzzinjack
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Re: Bonanza Gold

Post by cuzzinjack »

Below are some diagrams regarding mining with stulls. The first diagram shows stoping off of stulls, and the second shows the different uses for stulls. These came from https://www.911metallurgist.com.

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[/img]https://mollymarieprospect.com/update2/ ... es.jpg[img]

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Re: Bonanza Gold

Post by cuzzinjack »

Sorry here is the second that didn't post.

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