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Main waste rock dump at the Tintic Standard Mine.

Main waste rock dump at the Tintic Standard Mine.

In this post, we will report results and draw conclusions for our study of soil contamination in the Tintic Mining District. This study was supported by a grant from the American Chemical Society.

Students from Walden School of Liberal Arts brought back 42 samples of soils from the area in and around Eureka, Utah. Our purpose was to test for heavy metal contamination, especially lead. Previous tests done by the Utah Department of Health and the EPA showed lead contamination to be widespread throughout the town, due to the presence of historic concentration plants in the town and the use of mine waste rock as fill in many lots. Since there are mine dumps on the hillsides south of town, rain runoff also brought lead contamination into the residential areas.

Western side of the Swansea Consolidated mine dump near SIlver City.

Western side of the Swansea Consolidated mine dump near SIlver City.

These tests led the EPA to declare the town a Superfund project and spend $26 million to replace soils in some areas of town (but not all). They also placed limestone riprap over the mine dumps to prevent further runoff. The process took ten years and completely changed the look of the town, damaging or destroying several historic landmarks along the way, such as the headframes for the Eureka Hill and Gemini mines. Two landmarks, the Bullion Beck headframe and the Shea building, were restored. The rest have been left in ruins.

Middle section of the Swansea Consolidated mine dump near Silver City.

Middle section of the Swansea Consolidated mine dump near Silver City.

All of the tests we conducted were put into numerical form and entered into a spreadsheet so that we could compare the results. We used an ALTA II reflectance spectrometer to measure reflected light at eleven wavelengths, including four infrared wavelengths. We also tested the pH of the samples using several methods, including universal test strips, a garden soil test kit, and a pH meter. We tested for lead using a sodium rhodizonate solution, which changes from orange-red to pink in the presence of lead in neutral soils and to green or blue in the presence of lead in acidic soils. Please see our previous post for details on these tests. Since the rhodizonate test was qualitative, we assigned numbers depending on the color of the final solution so that some comparison could be made.

For the samples, we selected ten areas inside the town of Eureka, including some where the soil has been replaced and others where the soil is original. We tried to pick areas that were representative of the town as a whole. At each site, we sampled the surface soil and soil about six inches below the surface. We also sampled 12 sites outside of town, including areas away from town as controls and areas on or near exposed mine dumps, such as those from the Tintic Standard, Swansea Consolidated, and Tesora mines. We also took samples from gullies or washes downstream from mining areas and dumps, and from an exposed ore body (which has not been mined or processed) at a road cut along U.S. Highway 6.

Test Results:

Chart 1: Comparing Different pH Tests of Soil Samples. The readings taken with our portable pH meter provide the most consistent results (and can be done easiest in the field).

Chart 1: Comparing Different pH Tests of Soil Samples. The readings taken with our portable pH meter provide the most consistent results (and can be done easiest in the field).

As you can see from Chart 1 shown here, of the different methods we used to determine the soil pH, the pH meter was the most sensitive and consistently accurate. It was also easiest to use. It showed that most of the samples, were slightly acidic (between 6 and 7), but the samples taken from mine dumps and the areas immediately downstream were extremely acidic; in fact, some samples had a pH too low for our meter to read, which had a low limit of 2.5. Although not shown on this chart, the samples taken inside Eureka on our fourth collection trip all showed pHs near neutral (6 – 7).

Our lead test showed no discernable lead inside Eureka, even in soils that had not been replaced by the EPA. This is probably because our test is not sensitive enough for low lead levels. It becomes hard to distinguish the original color of the rhodizonate from the natural color of the soil unless there is enough lead present to create an obvious color change. In Chart 2, low levels of lead correspond very well with neutral pH soils.

Chart 2: Comparing Soil pH with Lead Levels. The lower the pH (more acidic) the soil samples were, the more lead was present with a correlation coefficient of rho = -0.876.

Chart 2: Comparing Soil pH with Lead Levels. The lower the pH (more acidic) the soil samples were, the more lead was present with a correlation coefficient of rho = -0.876.

The most interesting result of our study was to compare pH with lead levels. Chart 2 shows that the highest lead levels were found on or immediately downstream from mine dumps, which correlated very well with low pH levels with a correlation coefficient of rho = -0.876. Mine dump soils had high lead content and were highly acidic. Of course, this doesn’t imply causality: the high acid doesn’t cause lead, and the high lead probably doesn’t cause the acidity, but if one is present, so is the other.

Chart 3: Comparing Soils at Mine Dumps with Healthy Soil Using the ALTA II Reflectance Spectrometer. Healthier  soils were darker and richer in humus, whereas mine dump soils were pale and yellowish.

Chart 3: Comparing Soils at Mine Dumps with Healthy Soil Using the ALTA II Reflectance Spectrometer. Healthier
soils were darker and richer in humus, whereas mine dump soils were pale and yellowish.

In Chart 3, the reflectance spectrometer tests were inconclusive as far as detecting a signature for lead. We compared the results shown with samples of pure lead, pure galena (lead sulfide), and silver-lead ore. There were no obvious wavelengths that gave a definitive fingerprint for only lead.

The one useful result of the spectrometer tests was to confirm the overall health of the soil samples; those with lower percent reflectance overall were darker, richer, more healthy soils with more plant life growing. The lighter soils had less plant life and higher overall reflectances. The soils at mine dumps were yellowish to light purplish due to the presence of sulfur compounds, and these also had no plant life, lower pH, and higher lead.

Chart 4: Comparing the Levels of Nitrogen, Phosphorus, and Potassium in Soil Samples. The nitrogen and phosphorus tests gave no predictable results, whereas the potassium test showed higher levels of potassium in mine dump soils with high lead content (rho = .687).

Chart 4: Comparing the Levels of Nitrogen, Phosphorus, and Potassium in Soil Samples. The nitrogen and phosphorus tests gave no predictable results, whereas the potassium test showed higher levels of potassium in mine dump soils with high lead content (rho = .687).

Chart 4 shows the tests we conducted on soil nutrients. The nitrogen and phosphorus tests were inconclusive, and are probably due to the poor quality of the garden test kit we used. The potash (potassium) test did show higher potassium in the mine dump soils where lead levels were also highest, although the correlation was only moderate (rho = 0.687).

Conclusions:

A visual inspection of the mine dumps outside of Eureka, Utah in the Tintic Mining District shows that the waste rock and soils are highly contaminated. No plants grow on the dumps or in the gullies immediately below them. They are stained a bright yellowish-orange, and soils in the nearby gullies have layers of red, yellow, and even green. Overall, they are lighter and less rich than nearby soils with plant life. Our tests show that these mine dump soils are acidic and have high levels of lead contamination.

Similar mine dumps were located at the west end of town (around the Gemini and Bullion Beck headframes) and south of town (Chief Consolidated and Eagle and Bluebell mines). If the same pattern of contamination occurred there as what we found in the Swansea, Tesora, and Tintic Standard dumps, then it is likely that the soils downstream in the residential areas of town were also contaminated by lead and sulfur compounds. We did not find evidence of this in our tests of original soils inside town, but our test was not sensitive enough to find the lowest levels of lead. Soil pH throughout the town was slightly acidic, which may indicate sulfur or even lead content. We were not able to get the data from the original EPA tests.

Soil discoloration in the wash west of the main Swansea mine dump at Silver City.

Soil discoloration in the wash west of the main Swansea mine dump at Silver City.

Both pH and potassium content appear to be well correlated with lead content, with pH having a particularly high negative correlation (-0.876). Perhaps pH can be used as a marker, since it is easily measured. Where lead is suspected, a pH reading showing high acidity would indicate a strong possibility of lead. It would be interesting to see if the two measurements decouple as one travels further downstream from the mine dumps along washes and gullies. Do the lead and the acid travel the same distances?

Soil layers showing different types of contamination, in the middle wash downstream from the Swansea mine dump.

Soil layers showing different types of contamination, in the middle wash downstream from the Swansea mine dump.

Much remains to be tested. We have some additional grant funds that we will use to send four samples to an outside lab for detailed element analysis. I also hope to take all our samples to a local university and use an X-ray Fluorescence Spectrometer or Raman Spectrometer to get an accurate and precise readout of the lead levels and other heavy metal content. We need to determine the amount of sulfur compounds in the soils, and how that correlates with pH. We also need to pass our samples through a soil sieve and measure the relative sizes of particles and the amount of humus in each. We should test the mine dump soils to see if plants will grow in them compared to the other samples. Finally, we need to return to the site and collect more samples of other mine dumps, as well as the soils around and downstream from the dumps we’ve already tested. We need to determine how far the lead contamination and acidity travel down the washes and gullies and the extent to which the slope of the land affects this.

As with any field research study, it’s hard to keep all the variables constant. We’ve been careful and consistent with our tests, recording each location and using controlled testing conditions in the lab. But there are factors we can’t control. It could be that the low plant life on the dumps is simply because this is a desert, and plant life takes time to get established after soils are disturbed. The dumps were all dug up and the best materials were transferred to a leaching pile nearby in the 1980s. 30 years is not enough time for climax vegetation of sagebrush and juniper trees, but is enough time for grasses and low brush to grow. In general, soils in the area are poor in nutrients except where higher levels of water (such as in washes or gullies) allow more plants to grow and decay into better humus.

Staining on the asphalt where water draining off of the Swansea mine dump runs over the road near Silver City.

Staining on the asphalt where water draining off of the Swansea mine dump runs over the road near Silver City.

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Mine dump at the Tintic Standard Mine near Eureka, Utah

Mine dump at the Tintic Standard Mine near Eureka, Utah

On Tuesday, March 12, 2013 I took three students down to Eureka, Utah to collect our third set of soil samples for our Amercian Chemical Society grant project. Jeffrey, Sean, and Indie helped to collect samples and measure the soil pHs, as well as explore the history of the Tintic Mining District.

Mine dump with contaminated soils at the Tintic Standard Mine

Mine dump with contaminated soils at the Tintic Standard Mine

This time our first stop was at the old Tintic Standard Mine workings above Burgen and Dividend in the East Tintic District. Of all the ore bodies in the area, these on the east side of the Tintic Mountains were the last discovered and the Tintic Standard Mine was in full production by the 1920s. A reduction mill was built across Goshen Valley at the warm springs near Genola. Workers lived in a company town below the mine called Dividend. The mine produced well into the early 1940s, when it was partly shut down for the war effort, then re-opened. Work continued sporadically into the early 1970s.

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Collar and shaft at the Tintic Standard Mine. Even with a chain link fence around the hole, the loose soil at the collar could cave in and makes this shaft a dangerous place if you get too close.

There are still quite a few artifacts and ruins at the site, and care must be taken as there is a large vertical shaft with loose dirt around the collar, so you should stay well back from it. There is a large glory hole on the back hill and two water tanks further up, with the remains of a wooden ditch that brought water down to the company buildings and change room. The main portal to the mine went back from the change room, where there is still an old stove to keep the miners warm. That portal has been sealed off.

Stove in the change room at the main portal of the Tintic Standard Mine. This portal was active off and on into the 1970s.

Stove in the change room at the main portal of the Tintic Standard Mine. This portal was active off and on into the 1970s.

After exploring around, we collected some samples from the mine dump at the bottom of the hill where melting snow had created a clayey puddle. We also collected several samples along a trench that had been cut into the waste rock dump, where the soil was discolored with purplish or yellow deposits. The pH indicator needle pegged several times, showing an acidic pH of less than 3.5. It will be interesting to see what kind of lead content these samples have.

Jeffrey and Indie taking samples at the Tintic Standard Mine

Jeffrey and Indie taking samples at the Tintic Standard Mine

We then drove into Eureka and scouted around town for some additional sample sites to collect on our final trip on Thursday, as well as to look around the mining museum, old City Hall building with its jail in back, and the cemetery. I showed the students how miners worked the air-driven hammers and how water was sprayed into the holes through the center of the drill steel. We looked at the skips or man cages, the water removal buckets, and the mucker machine out front. We walked around Main Street, which was very quiet for a Tuesday afternoon. Only a few cars were driving through.

David Black by City Hall on Main Street in Eureka, Utah.

David Black by City Hall on Main Street in Eureka, Utah.

Water chute, tanks, and old foundation at the Tintic Standard Mine

Water chute, tanks, and old foundation at the Tintic Standard Mine

We drove out through the west end of town on Highway 6 and took a detour through the cemetery, recording with the Flip cameras as we went.  We explored around the town of Mammoth and collected samples in a wash at the mouth of Mammoth Canyon. We then went on around to the Swansea mine dumps at Silver City to continue collecting samples.

Ruins of the old power plant in Eureka. Heavy machinery moving through town has contributed to the deterioration of historic buildings like this one.

Ruins of the old power plant in Eureka. Heavy machinery moving through town has contributed to the deterioration of historic buildings like this one.

Since last week, the snow has mostly melted and the ground dried out to where we could walk on it in most places without leaving muddy footprints. We sampled in several washes running off the main dump and in soils between the washes where some scrub brush survives. The main wash feeding off of the dump had several layers of brightly colored soils, ranging from reds to yellows to even a shade of green.

Mammoth Mine, headframe, and glory hole. This was the deepest mine in the district, with the richest concentration of silver and gold ore.

Mammoth Mine, headframe, and glory hole. This was the deepest mine in the district, with the richest concentration of silver and gold ore.

I can see we need to do more studying here, to see how much lead and acidic runoff continue down these washes into the valley beyond. The runoff water has left a red stain on the asphalt of the road over a hundred yards from the main dump. The soil on and near the dump itself and in the bottom of the washes is devoid of life. Even though the last time this mine waste was dug up was the 1980s, when the leach pile nearby was created, no plant life has yet to colonize the contaminated soils in about 30 years.

Sean and Indie at the Silver City mine dump.

Sean and Indie at the Silver City mine dump.

David Black taking pH readings in the middle wash draining the mine dump at Silver City.

David Black taking pH readings in the middle wash draining the mine dump at Silver City.

All told we had an enjoyable and low-key trip, and even though it was overcast the day was fairly warm. We had now collected all the samples we needed outside the remediated zone.

Contaminated soils in the wash draining the Silver City mine dump.

Contaminated soils in the wash draining the Silver City mine dump.

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Science Research Class at Walden School on our second collection trip.

Science Research Class at Walden School on our second collection trip.

After our fall semester, my research science class ended and the two sections of chemistry were consolidated down to one, with me teaching a computer technology course third period instead of chemistry. Without the two classes that could support the Tintic soil analysis project, I had to put the project on hold until I could get some more students involved. We also had an unusually cold January and February, with snow staying on the ground. This hampered our ability to collect samples. Between 3rd and 4th terms we hold a two-week Intersession at Walden School of Liberal Arts that allows us to teach specialty courses, and I dedicated my course entirely to finishing the Tintic project.

Altogether five students took the course, including Jeffery, Indi, Sean, Jem, and Aaron. To finish collecting all the samples, we had to take three additional trips down to the Eureka area. We were fortunate that the weather cooperated and warmed up enough that the snow melted.

Our second collection trip was on March 5 to the area of the Knight Smelter, the cyanide leeching pile, and Silver City. We stopped at the Bullion Beck Headframe on the way to take a group shot.

Ruins of the Knight Smelter built by Jessie Knight to process silver ore.

Ruins of the Knight Smelter built by Jessie Knight to process silver ore.

The Knight Smelter was built by silver tycoon Jesse Knight, who made his initial fortune with the Humbug Mine, then expanded along the Iron Blossom lode. Eventually, Uncle Jesse needed a smelter to concentrate and refine the ores from his mines, and he built it south of Eureka near the Union Pacific line. To connect his mines with the smelter and the Union Pacific main line, he built a narrow gauge railroad so that the smaller engines could make the turns and the steeper grades. A fairly level grade was built around the hills into his mines, and the road I walked on to the Iron Blossom #2 last fall followed this old grade. Jesse Knight contributed quite a bit of money to what was then the fledgling Brigham Young Academy, now Brigham Young University. The Jesse Knight Building, where I had several classes, is named after him.

Tank foundations and kiln at the Knight Smelter

Tank foundations and kiln at the Knight Smelter

The technology for refining ore went through rapid change in the 1920s. The smelter only operated for about four years, at which point it became cheaper to ship the ore by rail to the more modern smelters in Murray. The same thing happened with the Tintic Standard Mine and the reduction mill near Goshen.

There isn’t much left of the Knight Smelter except crumbling foundations for the solution tanks, a few archways where the kilns stood, and a pile of slag. Just to the south is the leeching pile. During the 1980s the price of gold jumped up when we went off the gold standard and the price was allowed to rise. Investing gurus such as Warren Buffet were advising people to invest in gold, and that drove up the price even more. Now, all these old tailings and waste rock piles that hadn’t been economical to process suddenly were. A layer of thick plastic was laid down and the waste rock crushed and piled onto the plastic, then a solution of cyanide was pumped over the pile. The cyanide would chelate with the gold and silver and trickle down through the pile into its lowest area, where it was pumped out and transported for smelting. This same process is being used at the Cripple Creek and Victor gold mine in Colorado.

Collecting a sample inside the kiln at Knight Smelter

Collecting a sample inside the kiln at Knight Smelter

We walked into the old smelter ruins and identified spots where there would likely be contamination, such as inside the kiln and underneath the tanks. We saw that a layer of sand was laid down under the tanks over the original soil, which is now covered with new soil deposited since the 1920s. We also collected samples from the top of the leeching pile. I picked up some samples of slag as well.

This smelter took the original ore and concentrated it by crushing and chemical action, using both physical and chemical separations. Mercury was used to bind to the silver (amalgamation). The amalgam was then heated up in a kiln to drive off the mercury and leave silver and gold. Since the silver started out in a compound with a higher oxidation state (+1) and was now a metal with an oxidation state of 0, this process is also called reduction. There were several reduction mills in the Tintic District. The leftover ore, after heating, still contained appreciable amounts of iron and lead, and was dumped onto a heap in a molten state. This waste material is called slag.

Slag at the Knight Smelter.

Slag at the Knight Smelter.

Sample under the tank foundations. Notice the layering of the soil; a layer of sand was laid down under the tanks when they were first built which is now covered with new topsoil.

Sample under the tank foundations. Notice the layering of the soil; a layer of sand was laid down under the tanks when they were first built which is now covered with new topsoil.

We moved on to the waste rock pile at Silver City where the Swansea Consolidated mine was located. Here, water runoff since the pile was created in the 1980s has washed small gullies fanning out south of the pile, crossing the road, and going on down the valley. The asphalt on the road is stained red with the iron sulfides. We collected on the pile itself, and used a portable pH meter to test the soil at locations on and near the pile. It was still too muddy to walk around much, and we were getting short on time, so we packed back up and drove back to Provo. We collected ten samples from five sites on this trip.

Testing the soil around the Swansea mine dump. The pH is very low, under 3.0.

Testing the soil around the Swansea mine dump. The pH is very low, under 3.0.

Sample at the Swansea Consolidated dump near Silver City

Sample at the Swansea Consolidated dump near Silver City

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Welcome to Eureka sign on U.S. 6

Welcome to Eureka sign on U.S. 6

It’s time to take a break from recounting my tour through Colorado’s mining towns last summer and catch you up on what we’ve been doing this year at Walden School of Liberal Arts.

Maples in the fall near Eureka, Utah - with junipers and rabbit brush.

Maples in the fall near Eureka, Utah – with junipers and rabbit brush.

As mentioned earlier, we received a grant from the American Chemical Society to study lead contamination in the soils in Eureka, Utah and the surrounding area. The grant provided funds for travel, equipment, chemicals, and supplies. It took until early October to receive the money, so our first trip down had to wait until mid-October. It meant we wouldn’t have much daylight, but we’d have to do our best.

Canyon of Fire: Maples in the East Tintic Mountains

Canyon of Fire: Maples in the East Tintic Mountains

I’ve been gradually documenting the history of the area, collecting historical photos, taking photos around the town myself, etc. Back in 2009, I took a group of students with me to interview June McNulty, President of the Tintic Historical Society. He showed us through the museum and we videotaped the tour. Now, with this grant, we can tell the story of recent events in Eureka, especially the history of the EPA superfund project over the last ten years that cleaned up or covered up contaminated soils in the town.

TIntic HIgh School from the Godiva Mine site

TIntic HIgh School from the Godiva Mine site

My science research class researched the history of the area during first term while we were waiting for the grant funds. They identified 20 collection sites outside town using GoogleEarth. Some of these are old mine waste dumps, some are around smelter or concentration plants or leeching piles. Others are control sites outside the district. We were going to collaborate with students at Tintic High School, who were to collect from sites in town. Unfortunately, our collaboration fell through, so my students eventually collected from sites inside the town as well.

Valley of maple trees from a mine dump in the East Tintic Mountains

Valley of maple trees from a mine dump in the East Tintic Mountains

In preparation for our sample collection trips, I traveled down to the area to get some photos of fall foliage on Saturday, Sept. 22. I got there just at the right time, when the maples in the canyons were at their brightest. I photographed some areas along Highway 6 leading into town and filmed the maples in the canyons along the road leading over the top to Dividend. I then took videos around town by attaching a Flip camera to my left rearview mirror with a small claw-style tripod. I drove up to the Godiva mine site and took photos down toward the high school, then drove further up the canyon past the Knightsville site and hiked around some mine dumps further up. I had seen that there was a valley nestled inside the East Tintic Mountains from GoogleEarth and my 3D models of the area. There was a road leading along the edge of the hills, and I walked around as far as the site of the Iron Blossom #2 mine. The headframe there has recently collapsed. It was a nice trip and the photos turned out well. I also saw and photographed several deer.

Doe a Deer: A mule deer  doe in the East Tintic Mountains

Doe a Deer: A mule deer doe in the East Tintic Mountains

Ruins of the Irom Blossom #2 Headframe

Ruins of the Irom Blossom #2 Headframe

I took four students to the area on Oct. 19 and we collected samples and explored the area, including the road over Silver Pass. We first collected from some old evaporation ponds near Elberta where hot water pumped out from the Burgin mines was allowed to cool and settle before discharging it into Utah Lake. During the early 1980s, as I drove home from college to my hometown of Deseret, I would pass through this area and see the water steaming as it passed down the gulley to the ponds. This was the last time they had attempted to open the mines at Burgin. We sampled from two locations inside the old ponds, which can be reached by a short walk from Highway 6.

Collecting samples at the settling ponds near Elberta

Collecting samples at the settling ponds near Elberta

We then collected from the bottom of the wash at the mouth of the canyon leading up to Burgin. The soil here looked healthy and contained a combination of sand and humus. We then stopped at the old Burgin concentrator and took some pictures. I talked with the men at the main office of the Chief Consolidated Mine operations there about getting some samples from the tailings piles (they corrected me when I mentioned “tailings piles” around the headframes themselves and said those rocks were more properly called mine dumps or waste rock; tailings are the actual ore that has been processed).

Silver ore concentration plant at the Burgin mine

Silver ore concentration plant at the Burgin mine

We took photos around the Trixie headframe, then drove on up the canyon over the top of Silver Pass, which I had not done before. This was the opening of the deer hunt, so I didn’t want to venture too far from the road without orange clothing.

Headframe at the Trixie Mine above Burgin.

Headframe at the Trixie Mine above Burgin.

We also collected at a mine dump next to the road in Ruby Hollow, which I later identified as the Tesora Mine. The soil there had a bright yellow color and contained obvious sulfides. Part of the shaft is still there without much protection around it.

Collecting samples at the Tesora Mine dump in Ruby Gulch

Collecting samples at the Tesora Mine dump in Ruby Gulch

I also showed the students Silver City, the leeching pile from the 1980s when much of the waste rock and tailings were heaped up and cyanide solution was sprayed onto it, chelating the silver and gold out of the rocks. We stopped at the Bullion Beck headframe for photos and walked around the Tintic Mining Museum. It was late afternoon by then and time to get the students back.

Waste rock pile at the Swansea Consolidated Mine near Silver City

Waste rock pile at the Swansea Consolidated Mine near Silver City

Altogether we collected six samples from three sites and the students had a chance to get to know the area. I knew that we would have to be more productive on our next trips. Back at school, we did some simple pH tests and found the first two sites (Elberta Ponds and Burgin Wash) were near neutral pH, but the Tesora Mine samples were quite acidic, at a pH of about 3.5. Other tests would have to wait until we ordered the testing supplies.

Historic churches in Eureka, Utah.

Historic churches in Eureka, Utah.

Belt-driven drill press at the Tintic Mining Museum

Belt-driven drill press at the Tintic Mining Museum

Downtown Eureka, Utah: 2012Belt-driven drill press at the Tintic Mining Museum

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