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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 near Silverton, Coloado

Mine near Silverton, Coloado

My exploration of the Mayflower Mill took quite a bit of time, but it was worth detouring back to Silverton just to see it. I was quite hungry by the time I finished, but I stopped at some interpretive signs along the road back to town, including a road map of the area showing the roads over Cinnamon and Engineer Passes to Lake City. I would like to explore these routes, but knew my minivan was no match for those passes. I’ll take the long way round.

History of mining around Silverton, Colorado.

History of mining around Silverton, Colorado.

Closer to Silverton was a display on the tailings from the Mayflower Mill and a description of the Silver Lake Mill across the valley, as well as the mansion called Waldheim that was built by Edward and Lena Stoiber, who also built the mill. It was eventually sold to the Guggenheims and demolished for salvage in the 1940s.

Mayflower Mill and tailings pile. The Silver Lake Mill was across the Animas River from the Mayflower.

Mayflower Mill and tailings pile. The Silver Lake Mill was across the Animas River from the Mayflower.

Back in Silverton, I found a promising place to eat and had a tasty lunch of buffalo chicken wings at Handlebar’s Restaurant and Saloon. Certainly much better than the place I ate at on Tuesday. The train crowd was leaving by the time I finished and the town was more relaxed.

Main Street in Silverton, Colorado.

Main Street in Silverton, Colorado.

I had one more attraction to see on my Silverton Heritage Pass, and that was the San Juan County Historical Society Mining Heritage Center housed in the old Silverton jail. Downstairs was an excellent exhibit of local minerals, and the jail itself was interesting. From the jail, you pass through a tunnel and connect with another building to see the Heritage Museum. It had good displays of mining equipment and how it was used, including engineer’s transits, safety equipment, and general artifacts from the town itself.

Gold ore from the San Juan Mountains on display in the Silverton museum.

Gold ore from the San Juan Mountains on display in the San Juan County Historical Society Mining Heritage Center in Silverton.

More gold ore in the Silverton museum.

More gold ore in the Silverton museum.

Silverton got its start after the Brunot Treaty of 1873 opened the area to settlement and pushed the Ute Indians out. Almost immediately mining began in the area and continued until 1991 when the last mine shut down. At its height in the 1880s, Silverton’s population reached 3000, with many coming from European countries. The mines advertized in foreign newspapers and promised land and wealth. Usually the younger male members of families came first, hoping to save enough money to send for the rest of their families.

Silver ore from the San Juan Mtns., on display in the Silverton museum.

Silver ore from the San Juan Mtns., on display in the Silverton museum.

Silverton was a rough town, with gambling, saloons, and other forms of recreation that led to the need for a good jail. Built in 1902, the jail was rarely empty. The jailer’s family lived on the main floor and the cells were on the top floors, with storage in the basement. Eventually, as mining dwindled and the population decreased, the jail was shut down and used to store artifacts for a proposed museum, which finally opened in 1965. Now, a large addition has become the Mining Heritage Center.

Copper ore on display in the Silverton, Co. museum.

Copper ore on display in the Silverton museum.

After completing my tour, I drove out of town on Highway 550 and crossed over Molas Pass again, returning to Durango for the third time in five days. I did stop at the train station one last time, but they still had not seen my hat. Oh well! I drove on out of town on Highway 160 toward Pagosa Springs.

Typical mine blacksmith shop, recreated in the Silverton Heritage Museum.

Typical mine blacksmith shop, recreated in the Silverton museum.

It was a pleasant drive, threatening rain but never more than a light drizzle. It’s about 60 miles from Durango around to Pagosa Springs, which surprised me for being such a large town. I didn’t stop to explore, as I was already behind schedule to get to my camp for the night. It must have a fairly large airport judging from the midsized jet I saw taking off.

Progression of miner's hats and lamps.

Progression of miner’s hats and lamps.

Highway 160 continued on to Wolf Creek Pass. I stopped at a scenic pullout along the switchbacks leading up to the pass and could see a long way down a glacial valley to the west. This is the site of one of the old songs by C. W. McCall, called “Wolf Creek Pass.” The song follows the misadventures of truck driver Earl and his companion, whose 1948 Peterbilt 18-wheeler goes out of control driving down Wolf Creek Pass, until they crash into a feed store in Pagosa Springs, losing most of their cargo of chickens along the way.

Miner's carbide lamp and cross-section diagram.

Miner’s carbide lamp and cross-section diagram.

I looked at Earl and his eyes was wide

His lip was curled, and his leg was fried.

And his hand was froze to the wheel like a tongue to a sled in the middle of a blizzard.

I says, “Earl, I’m not the type to complain

But the time has come for me to explain

That if you don’t apply some brake real soon, they’re gonna have to pick us up with a stick and a spoon…”

(“Wolf Creek Pass” written by Bill Fries and Chip Davis, sung by C.W. McCall)

Drill steals, including single and double jacks and Leyner drill bits.

Drill steals, including single and double jacks and Leyner drill bits.

Interestingly enough, another song by C. W. McCall is entitled “Black Bear Road” and talks of the legendary jeep route between Telluride and Ouray. Since I started out in Ouray this morning, I’ve definitely been in C. W. McCall country.

Jail cell in the old Silverton, Colorado jail.

Jail cell in the old Silverton, Colorado jail.

But the funny thing is, C. W. McCall never existed. It was a pseudonym of songwriter Bill Fries who, along with Chip Davis, worked for an advertising company in Omaha. They were hired to do a marketing campaign for the Metz Baking Company, which made Old Home Bread. They came up with a trucker named C. W. McCall who delivered Old Home Bread to the Old Home Filler-Up and Keep On a Truckin’ Café, where he meets with waitress Mavis Davis. The commercials were a big hit and won the Clio Award. Bill and Chip decided to take the C. W. McCall persona on the road, and released several “outlaw country” albums. In 1976 they ignited the citizen band radio craze with the song “Convoy,” which earned them a gold record.

Mine engineer's surveying transit.

Mine engineer’s surveying transit.

While on the road, Chip began experimenting with a fusion of medieval music with modern instruments and synthesizers and created the group called Mannheim Steamroller. The first album was rejected by all the major record labels, so Chip set up his own record label called American Gramaphone. Their Fresh Aire albums, especially the Christmas albums, are still among my favorite.

1930s photo of Silverton, Colorado with a large mill complex in the background.

1930s photo of Silverton, Colorado with a large mill complex in the background.

Bill Fries eventually moved to Ouray, Colorado and was elected mayor there in 1986.

View from Wolf Creek Pass toward Pagosa Springs.

View from Wolf Creek Pass toward Pagosa Springs.

It was raining a bit more heavily as I crossed over Wolf Creek Pass but lightened up as I headed down into South Fork. I had a reservation at a large RV park a short distance up Highway 149. I had set up the reservation long before I had the trouble with my tire and had to modify my itinerary; originally, I was going to come in from the north on Highway 149. Fortunately, even though I was late, the manager was still in the office making bread for a bake sale in the commons room. My camping spot was right next to this room and the spot was so narrow my tent was literally wedged between the building and my neighbor’s pop-up tent. I covered my tent with a tarp in case of rain and to keep out the bright light on the side of the building. I ate supper, got my electronics charged up, uploaded my photos, and slept well despite the light.

Sign near the Silverton Museum detailing the history of the area.

Sign near the Silverto museum detailing the history of the area.

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