Sluice Concentrates

If you are using a sluice box, at the end of the day you are left with black sand (which is much heavier than the quartz and feldspar sands which are light colored) and hopefully gold in your sluice box. Every attempt is made to easily remove most of the gold next to the river, but there is always some left in the sands and so you bring them home. Thus the predicament that most prospectors are faced with is born, fine gold and black sands.

The combination of the two can be a headache, especially if all you have to work with is a pan.  When I started prospecting, I bought a spiral panning machine that separates gold or heavy materials out, called the Desert Fox.  I came very close to selling the thing, because I was under the impression that it didn't work at all. I would run all of my concentrates at different angles and water speeds and get nothing but black sand, no matter what I did. It took me a while to figure out that there wasn't actually any gold in the material I was running(duh).

Once I actually started bringing home fine gold in the concentrates, the Desert Fox really showed its true potential. I'm now a solid believer that it can separate gemstones or any denser material for that matter, and it can do so quite efficiently when set up proper. Its ease actually allows me time to do work more while I'm at the river, instead of panning out my concentrates where there is water.

My process goes something like this:

When I run material, I use my snifter bottle to pick up gold I can see on the indicator matting. This gives me a peace of mind that the gold isn't going to travel further back into the sluice, where it has a greater chance of getting washed out. Also, I have the bulk of my gold (or so I hope) to pan out at the end of the day, but its always a manageable amount of black sand. Everything else sits in the sluice until a clean-up, where I dump the whole sluice load into a dedicated concentrate bucket.

This represents two days of sluicing. The concentrates come from Cache Creek BLM area by Granite, CO

When I take this home, the first step is to classify the material through a set of screens. The screens that I use are 1/4", 12, 30, and 50 mesh. The mesh size is measured by the number of openings in a linear inch.  I dump the black sands on the screens that are set up on a bucket. I take another bucket full of water and slowly pour it through while shaking to classify it.

All of this material was removed using a magnet. Magnetite retains the magnetic orientation of when it
crystallized due to its atomic structure, and will retain its magnetism for a very long time.

Once classified, I run them in the Desert fox starting with the material between 50 and 30 mesh, and move to the coarser material. Although the machine claims to be able to separate clean gold, I haven't been able to do so without feeling like I have lost some. I always set it up so that it takes a bit of black sands too, that way I can be absolutely sure I have gotten everything I can. When the material is well classified, and with the aid of a magnet, panning the gold from the black sands is a breeze and takes only a minute or two to get clean gold.

Some processed gold from the Desert Fox

Desert Fox doing what it does best.

I'm not sure that this machine can competently separate the fine, fine gold that slips through the 50 mesh screen, so I have been saving this material in a bucket for quite some time now. Ideally, I would like to run it through the Fox and then through a Blue Bowl, because I have heard they are better for this sized material. A Blue Bowl uses spinning water that empties into a hole in the middle of a bowl to allow the fine gold to separate. I would also be willing to invest in screens in the 100, 200 and 300 range, because I'm sure that there is a lot of gold in there that is otherwise practically inseparable.

I almost didn't run my 20+ material through the Desert Fox, because I thought that it might be easier to hand pan. I'm very glad that I did, though. When I was not expecting much gold at all from this material, the big guy on the right jumped out and ran up the spiral. It is my first nugget to register on a scale, weighing in at a massive .1 grams, making its worth around $5 currently.

For two days of moving around 15-20 five gallon buckets of dirt each day, its not a very good paycheck.
For spending two days outdoors, in the sun, and next to a creek with a huge smile the whole time, it is priceless.

Gross Reservoir

As the spring months roll around, there comes about this insatiable desire to get outside. After being bundled up all winter and working hard to finish my final exams, it was a great time to go and enjoy the warm weather.

I chose to go and spend a night on the shores of Gross Reservoir, it was an easy mile hike in, and I was hoping to gain access to some potential gold deposits in the gravels of South Boulder Creek, which have proven themselves historically and in my own pan.

The reservoir, approximately sixty feet below its full level, was amazingly desolate. Winds would blow the sand and mud from the exposed sides, whipping them into dirt devils and creating characteristic carvings on the sides of the banks. The bottom, covered with what would be a thick, oozing mud was dessicated into dramatic flats of mud cracks.

The river here was very interesting, because it flowed through a large basin of wind-blown sand with little to alter its flow. This last semester, in my Sedimentology and Stratrigraphy class, we learned how to identify the mechanics and formations of these river deposits. They were most certainly present and identifiable, I picked out parallel cross-laminations, some subaqueous dunes, and longitudinal point bars, all characteristic of a sandy braided river system.

Crayfish skeletons were abundant on the shores. As I stepped into the river to sample a long gravelly bar for gold, I almost crushed this very picture-compliant guy. 

I spent some time the next day sampling the area where the river meets the reservoir for gold. Most surface bars held some fine dust, and usually a decent amount of it. I didn't find anything that I could even call a flake, so i've concluded that the size of the gold depends on the size of the flood moving the sediments in. Finding a deposit from a large flood could contain some coarser gold.

Abandoned fluorite mine of Jamestown, CO

The Jamestown and Ward region, located up Lefthand Canyon endeared years of mining success during its booms, and like all other mining regions, misfortune and busts. The region produced gold, silver, lead, copper, and fluorite (then called fluorospar). Low grade fluorite is used as a flux in the melting of iron to increase fluidity, and so the region boomed during both world wars. Now, only a few year time residents and summer cabins remain in this area, but the aftermath of the mining is evident. Holes are dug into the side of the hills everywhere, and the yellow dirt can be seen pouring out onto the hills in many areas. These yellow rocks are sulfide minerals, which are frequently associated with veins of precious metals that have been deposited hydrothermally. These sulfides, when exposed to water with higher surface area react to form hydrosulfuric acid.

Chemically,

 2H20 + S ---- 2H2S +02

The additional oxygen molecule often proceeds to react to form carbon dioxide. The water that runs off  is then considered acid mine drainage. This region has a huge problem with this, and there are some mines designated as superfund sites that need to be cleaned up. One attempt to remedy this has been to put bags of limestone below the tailings piles, so that it will hopefully absorb the acid before it reaches the stream.

My mineralogy teacher, Joe Smyth, took us on a field trip up left hand canyon, and showed us some pegmatites, high grade metamorphic rocks, and then this fluorite mine. The few minutes we spent there wasn't enough for me, I have been back a few times exploring the area. The fluorite there is a pretty purple,  but doesn't occur in very solid crystals. The mine was originally a gold mine, but later was further developed for its fluorite.

The main pit. Fractures and fisures have been stained black by manganese bearing waters.

The pit was dug directly into the hillside, and the walls are about 60 to 80 feet tall. An old headframe sits on what used to be the side of the hill, and above the tailings pile. The tailings are a fine yellow dirt, that erodes easily into steep slopes, exposing the iron and wood fragments that make it so uninviting. The interior of the pit is also filled with this fine tan-yellow dirt, but no tetanus shot required.

Looking down at the side shaft. Pick axe for scale, ~3.5 ft long.

A small hole dug down connects through to the main pit. Its really quite tempting to climb down through it, but this is probably ill-advised with the unstable condition of the rocks. This shaft drops about fifteen feet before connecting horizontally with the main pit, still about forty or fifty feet above the bottom of the pit.

Quartz crystals in matrix.

                                                                                                                                                            










Some purple fluorite can be found in the walls and floor of the pit. It is quite rotted and is often found as a purple powder. Crystals here are rare, but I have found weathered cubes in some of the bigger boulders on the floor of the mine. Fluorite has a cubic crystal habit, and can form octahedrons, cubes, and plenty of like variations. On this trip, I wasn't looking for fluorite. I visited some outcrops above the mine and found some quartz crystals exposed from weathering on some fissures. They are a grey color, and embedded in matrix. I managed to chip away a crystal or two.

Two small, loose crystals.

Clear Creek Gold

With the few days left I had of spring break, and after being chased out of the central mountains by a huge storm front, I wanted to dig for some gold for a few days.  I headed out to Clear Creek early one morning to look for a place to dig. I was hoping to find some coarse, big gold that I knew was out here!

A wildfire in the gulch to the North had been spreading quickly, and on my drive up I witnessed some of the power and proximity of this fire. The canyon is curvy, and the hills on the side are steep. As I drove along on the road, without any cars around, I noticed that on the top of the ridge the trees were actually on fire. A 20' pine tree was a ball a flames, and the ground around it had 4-5 foot flames all around. It was absurd to think that the forest was burning right there so close to the road. I got another mile or two up the canyon to where I spotted a Jeep that I recognized as a man, David that I had met one other time before on the North Fork of Clear Creek.

I parked and walked down to where he was working. After doing a little sample panning, I decided on a spot on the upper part of this placer bar behind a large rounded boulder. The spot was showing a few specks a few feet down, but nothing too promising. I wasn't too far from David, and we would chat every once in a while about the history of the area, and our theories on the gold. After an hour or two, police sirens on the road caught my attention. A Jefferson County sheriff was yelling at us to leave, because the canyon was closing. We both began hurrying to clean up and pack our stuff back to our cars. By the time we could pack our stuff up, 3 other officers stopped and yelled at us to leave. David asked if I wanted to go  to his hole up the creek and dig there. He said he had been finding small nuggets, and guaranteed that I would too if I came with him. With my doubts, I followed him to his spot (which he asks I do not share the location of) where he had quite a large hole dug. Surrounding these boulders buried deep in the river, he said he had been getting the gold.

I began to dig, which wasn't easy because the hole was so deep and the footing precarious. My thigh-high waders were about an inch away from being filled in with cold, cold water, and in late March, the air temperature isn't quite optimal for swimming. I sluiced out all of my material, without seeing any gold that I could get too excited about. As it got dark, I cleaned up my sluice, and as I washed the top material into the bucket, there it was!
 
A Nugget!

My first decent sized piece of gold. It hasn't traveled very far, and is almost wiry.

Another day's work. Its not easy, but nobody said it would be.

A piece of gold that I could pick up and hold. I got very excited, and finished cleaning up with a huge smile on my face. We agreed to meet there the next morning, and continue digging. We did so for the next three days, and ended up finding some good gold.

In search of Barite and Topaz

The Granitic Tarryall Mountains, power lines and road signs.

   Some people choose to go to Mexico for spring vacation. Some people choose California, more choose Las Vegas, and more still like to take their break in Moab, Utah. Myself, I like Colorado.

I began my vacation by driving to Tarryall, to look for some Topaz that was rumored to be around these parts. The granitic mountains here are very pretty, and the scar of the massive Hayman fire that ripped through here years ago is beginning to heal. I spent the afternoon hiking the region accessible from Spruce Campground (or something like that), and looking at a lot of granite. Topaz crystals form in granite pegmatites, which are known to be found (in abundance) in the region.

A rundown on pegmatites:

      As a large body of granite is cooling (granite by definition cools very slowly), it is changing from a liquid to a solid. Large crystals are forming as the rock cools, but in a certain sequence of the available minerals. All materials melt at different temperatures, thus they will crystallize and come out of solution in the opposite order. As the rock is cooling, minerals that remain in solution tend to be rare earth minerals, and concentrate along with quartz, which has a very low melting/crystallizing temperature and form pegmatites. Beryl (aquamarine), Tourmaline, and Topaz are all examples of the gemstones that can form from the extremely slow cooling pegmatites. 

A perfect example of a meandering river, with some geese
standing on rocks most likely moved by glaciers

I found one pegmatite that had been excavated. The opening was 20' wide and 30' tall, with very steep sides. Contrasting to the entire mountainside, the walls were made up entirely of quartz. I carefully examined the walls for any sign of pockets where the crystals could form, but didn't see anything. The tailings didn't look too promising either, but I figured if somebody had come all this way to dig out that much rock, they had ought to have a darn good reason. I camped that night by the Colorado Topaz Mine, where an old screener box was sitting, without the screen. It looked like they had been digging around all of the large granite boulder sitting through the camp area. The nearby Colorado Topaz mine  is a  placer deposit of gem-quality Topaz, and has been a very sound producer. In the morning, I dug up a bucket of my own material to screen out when it wasn't freezing. 

The hole in which the barite was found. For scale, the green
screen in the upper part of the picture fits snugly inside the top of
a 5 gallon bucket. It was kinda nice to get out of the wind.

Driving on to the next stop, a barite crystal locality, I soon found myself in someone else's hole. Barite is a heavy mineral used for oil drilling as a thick mud, but occurs in CO in a rare blue variety. They occur in sedimentary rocks, and a formed under low pressure and temperature. They had dug down to the crystals, and must have either had their fill or gotten tired, because they left them exposed in the bottom of the hole. Sure, it wasn't the best hole for proper digging posture, and there wasn't much room to move limbs about, but it gave plenty of license for creativity.  After spending some time cleaning the specimens up, some are quite pretty, and I hope to return soon to dig out some more. The crystals will absorb UV light throughout the day and become more and more blue, so they are very pretty in windowsills.

Here the elaborate crystals are exposed in a mud filled pocket.
The bulk of the mud easily washes away, but the cracks are
filled in with mud, calcite, and iron oxide, but this is all
 easily dissolvable in a strong acid.

In the same day, I drove to Nathrop by Buena Vista, and in the whipping winds and ocasional flurries of snow went searching for garnets and yellow topaz that was rumored to occur there. It was so cold, so I practically ran to the top of the mountain that is of a certain rhyolite that is quite distinguishable. I looked all along the way, but only found one small crystal that I think has a chance of being a topaz because it is squarish and yellow/brown. I found out later that you need to split lots of rocks to find the gems, which I didn't split a single one. Regardless it was beneficial just to look at the geology of the area that they occur in, and now I know just where to go and what to do when I return this summer.

After and exhausting two days (and with a large oncoming storm front) I drove back to Boulder, ready for warmth. When I got there, I sat down, and wished I was still digging in a hole somewhere.

I guess thats just how it is.

A Weekend on the Platte

One day's worth of work. Note the piece of dull gray platinum.

 After taking advantage of the good weather and heading down to my new favorite placer deposit by Commerce City, I found myself digging in the sun, and finding some gold too. I had located this spot off of a website by a guy who lives in Denver and sells prospecting equipment. He was testing out his products at this placer and made quite the discovery.
     Turns out though, its not that new of news. These deposits are the same as the ones that the first pioneer dipped their shovels into on their way to California. Most prospectors didn't think much of it, and headed west. When they didn't find their fortunes in California, they thought back to the Platte that they found that fine gold in. From these same placers, they worked west into the mountains and found all of the lode deposits. They were again mined during the depression, which in my opinion strikes a bell will all of the digging has ocurred at this spot.

The second day's work. This is just what I picked up from
pans and the sluice, even more is in the concentrates!

        Fine gold is in abundance at this spot, and found about 6 inches below the surface. Gold is found in all areas of the placer, but the larger pieces are concentrated in a straight line. Test pans revealed on average 2-3 decent pieces and about 15-20 very fine colors to the pan. One day I was out I only classified my material to 1/4", and the other 1/8". When I classified smaller, I found my sluice worked much better, and my overall gold recovery was better, but this could also be because I dug along the "gold line".
 It was fun to finally get some gold! I estimate about 1.5 grams from the weekend, but I still have to run all the sluice cons through the desert fox, and then clean and dry all of the gold. Lots of work, but it is worth it!

Tour de Colorado ~ Part I

One year, for our high school spring break, three other friend and I decided to take my friends minivan, his saint bernard named "Bear" and drive it around Colorado for a week. Our plan roughly involved a loop, beginning in Fort Collins, in the Northern part of the front range down to Ridgway, in the Southwestern side of the state. Our friend's brother had a cabin there. We had no idea what Colorado had in store for us.

Snow falling at the sand dunes as the sun sets

Our first destination was the great sand dunes. We, being young, paid the national park fee, and went and found somewhere where we could camp wherever we wanted, instead of the cramp-grounds that they wanted us to go to. It's more fun that way. We bedded down for the night as it had begun to snow, and it was cold. When we awoke, there was about a quarter inch of snow blanketing the whole area, but the hot sun was working fast to melt it. By the time that we had gotten up and eaten breakfast, the snow was almost gone. We took our snowboards out onto the sand dunes and gave it a shot. You had to go straight for a long time to gain any appreciable speed, because the sand wasn't steep, but it was still fun. There is still sand on my snowboard
waxing iron, even this many years later. We hike to the tallest dune we could find, and basked in the hot spring sun. The views of the snow-capped Sangre de Cristo range were amazing. Now, looking back I realized I could have learned so much about sedimentary geology at this location. There are so many processes specific to sand dunes that create unique sedimentary rocks. Medano creek, the river channel that runs on the flank of the sand dunes has been subject to many geologic studies. The properties of the creek is very unique, flooding and subsiding periodically as the water seeps underground through the sand.

Our next destination was Ridgway, where Forrest's brother had a cabin.  We had heard about some hot springs, called Valley View hot springs, close to a town called Crestone. After locating the hot springs, and traveling down quite possibly the worlds straightest road, we found out that it was $15 admission for the day.  Being on a strict budget that did not allow for this expenditure, we camped out nearby and waited for nightfall, since the hot springs closed at 6.  We hiked in around 11 p.m. fearful that we would be heard and discovered. It was a stealth operation, and we were all as quiet as possible, but we didn't really know where the hot springs were or what to expect. Would there be a guard or nightwatch? People still soaking from the day?  We found a drainage with a strong sulfur odor, dipped a finger in and found that it was warm. Walking downstream, we found a pool for soaking, and the beginning of a long pathway connecting many other pools. In silence, we stripped to the nude and slipped in. Amazing. It wasn't long before we noticed a little dot on the side of the pool, that we were convinced was a motion detecting device. We were all scared and panicked, and about to run when we saw another. As it turns out, they were fireflies that lived next to the vapor coming from the pond, it was warm year-round and never froze, so they could live happily. I had never before seen one my whole life, and didn't even think they could live in Colorado. I have never seen another though, either. We spent the whole night soaking under a bright, full moon with completely clear skies. We checked the clock when we returned to camp, it was around 4:45 a.m. I don't think that i'll ever forget that night.

The next day, after sleeping in all day, we continued on our way to Ridgway, but not without heading down to Crestone where Forrest had said the architecture was neat. It really was, one neighborhood had hardly a single conventional house in it! Some were dodecahedrons, which is a flat dome shape that is supposedly more energy efficient. Plenty of sod houses, and ones that blended right into the environment and were hard to pick out. Houses in construction there revealed that these were not of normal composition. They were being built out of bags of material, like sand bags, and not with plywood and shingles. It was really neat to see how the "green" housing had spread through this community, it was really a strong feeling even just driving by these houses. I'm sure that much more thought goes into the interior and reasons for design of the house that we were simply unaware of.

We finally made it to Ridgway, which is below Ouray and Red Mountain Pass, which is all spectacularly beautiful.