GEO MRI | NMR Roadside Service in the Wild West: Subsurface Stability Detection @ Gold King Mine|CO

Realm of work: Geotechnics | Mining

Logging Toolstrings: NMR borehole sonde, 1.75 inch diameter | Gamma-Induction sonde

Silverton, Colorado: Once an El Dorado for gold and silver desperadoes, later a natural setting for famous Hollywood cowboy films (“Westerns”), is now a dream landscape for motorcycle enthusiasts, skiers, and a sought-after tourist destination. The long way from Seattle to the first site of our Roadside GEO-MRT | NMR service tour through the Wild West was characterized by beautiful natural impressions in Oregon, Idaho and Utah, and the journey to the former mining capital in Colorado invigorating. Once the traveler arrives there today, one is immediately captured by the charm of the small town and the natural beauty of the surrounding area.

But what was the reality at the time of the mining boom? And what impact did this industry have on nature?

Fig. 1: The long journey from Seattle via Oregon, Idaho, and Utah to Colorado to the former mining mecca of Silverton|CO was worth the trip alone. For the many motorcyclists and tourists from all over the world, this small town at an altitude of roughly 9,800 ft is an absolute highlight. The working experience at an altitude of almost 12,000 ft nearby the old mining town was equally enjoyable.

Beginning in the 1860s, Silverton | Colorado was the Mecca of the Wild West for those who wanted to venture out and into the harsh conditions of nature and the dangerous mining business. The Heritage Mining | Prison Museum in Silverton captures highly valuable impressions of this time and the development of the mining industry in the region, which over the decades mined tons of gold, silver, later also zinc, copper, lead, and other valuable minerals. The water of the surrounding rivers and rapids in the region still bears witness to the strain on nature caused by this human over-exploitation -- on which we all depend, always and every day, everywhere in the world.

Fig. 2.: Silverton | CO is home to the Mining Heritage museum that looks rather inconspicuous from the outside, yet impressively presents and describes the history of underground mining as well as the harsh “law & order” mentality of the responsible law enforcement officers. The tour through the 3 floors of the building can easily take 3-4 hours. The golden-orange color of the small rapids near the museum still bears witness to the environmental damage of this centuries-long over-exploitation of nature in the form of extremely mineral-rich input from the mine runoff.

Today it is hard to imagine how the people of the 19th century flocked here from all directions (including Europe, especially Ireland and Germany) in pursuit of their own luck. They literally dug, blasted and worked themselves through the red-orange mountains of this region for decades. Even today, venturing out into the mountains along the steep slopes can still make you feel a bit uneasy, and I have no idea how people managed back then this kind of operation on horses, carriages, mules, and on foot (a good read about this time is F.B. Wildfang's book about the "San Juan Skyway".) Plus cold, heat, water, lack of nutrition, etc. - and of course the constant danger during the underground mining operations. What a life this must have been!

Fig. 3: The dangers for the workforce who sought their fortune in mining were diverse: from cold to heat, water | lack of nutrition, including the possibility of a serious fall in sometimes extremely difficult terrain. Even today, if you venture into the mountains in a 4-wheel truck instead of a horse-drawn carriage or a mule, you can sometimes feel a bit uneasy near the steep slopes and on unpredictably unstable ground.

Some people got rich from the boom in the hard mining business in this region, which started a good 160 years ago and lasted well into the 20th century (albeit with interruptions). However, quite a few of the many fortune hunters ruined their health in the process and left behind less than they had previously had.

Fig. 4: Like everywhere else in the world, the mine was a place of special human solidarity, which was often further strengthened by myth and legend. The Mining Heritage Museum in Silverton | CO is also in this regard a treasure trove of information - especially for all those who feel connected to "mining" and know a little about the “Glück-Auf | Good-Luck-To-You!” mentality of the mining guild around the world.

But as with all extreme situations in life, this was a time of innovation and development - in this case for the mining industry worldwide, plus the railway technology as chief means of surface transportation of material and personnel to and from the mine. Also blacksmithing was of particular importance. Some of the equipment that had been developed for underground mining in this region is still elsewhere in use today.

Fig. 5: Devices for penetrating deep into the ground have naturally been improved and further optimized over time. This not only increased economic returns, but also enhanced safety conditions for the miners. The Silverton Mining Heritage Museum has a wealth of exhibited devices, tools and machinery, and impressively showcases the history and development of the applied technologies.

As elsewhere in the world, underground mining in the region was, of course, dependent on the necessary infrastructure and installations on the surface in order to serve and support the highly complex value chain of the entire mining production: from prospecting the rock, to deeply penetrating into the earth, to the removal of tons of material, the subsequent extraction of the minerals into the individual components, the precise measurement of the mineral weight proportions, and much more.

Fig. 6: A highly detail-oriented model replica of the infrastructure for receiving and processing the material mined underground, shows the complexity of the entire workflow and process of mining of the valuable goods of the Under-Earth. Historical images, original machines and operational equipment (and of course rock samples and mineral specimen of all kinds) offer visitors the opportunity to get a clear, up-close picture of the mining activities in the region between the 1860-ties to the 1990-ties.

Even though the gold and silver rush was the initial main driving force for the underground mining activities in the mountains near the Silverton base camp, over time other precious metals became more and more socially relevant (for example, lead for batteries). This also affected and promoted the production line for extracting copper, zinc and other semi-precious metals.

Fig. 7: A diverse body of specimen from the profitable mining business in the San Juan Mountains are exhibited at the museum: From gold to silver, to other precious metals and crystal treasures, you will find a collection of rock samples that is unparalleled in the world.

Since anthropogenic environmental disasters have repeatedly occurred over time due to the mining industry in this region, the entire area is now monitored very closely while regenerative measures are carried out on the natural environment. To make a contribution to this mammoth task (similar to the Yanacocha Mine | Peru), our service was called to action: Data obtained with Vista-Clara Inc. innovative GEO-MRT | NMR technology provides important additional value to examine the subsurface stability of this “anthropogenic geology”.

In order to carry out NMR-Logging at approximately 12,000 ft above sea level, we had to conduct at first so-called Gamma | Induction measurements to identify potential hazards to our NMR tools from the presence of hidden metallic objects left behind in the underground. Such type of “contamination” was to be expected (as the museum demonstrates impressively) considering the use of the many pieces of heavy equipment during the mining era. Such massive metal objects could seriously damage the magnets and electronics of the GEO-MRI | NMR probes.

Hence, rather being "safe than sorry", we also re-verified the depth of the individual drill holes using a simple measuring tape contraption. We thereby also cross-checked whether any obstructions blocked the pathway of the tool strings descending from the top to the bottom of the borehole.

Fig. 8: A simple depth determination in each borehole provides a certain level of security that the passage from the earth's surface to the end of the borehole does not have any obstacles that could cause the measuring probe to jam in the PVC pipe or that the measurement could end prematurely. Induction measurements were then carried out (essentially the reverse of a resistance measurement) in combination with a gamma (natural radiation) measurement. This made it possible to ensure that there were no metallic objects underground that could literally destroy our NMR measuring probe.

After we had successfully completed these preliminary examinations, we finally started with the GEO-MRI | NMR measurements. The results were initially not very encouraging, which meant we had to figure out at first how we could optimize our efforts (which we did by the time we started our last day: Day#3).

Luckily, my field work assistant for this project, Brandon Kingsbury (actually an experienced leader of an entire project manager group @ Tetra-Tech | Montana) is about 3x as strong as me. This made it possible to accomplish our tasks and goals within the given time window of 3 days, and ultimately achieve very good results.

Fig. 9: NMR (GEO-MRT) measurements in 3 boreholes on the rubble mounds of man-made (“anthropogenic”) geology at one of the entrances to the Gold King Mine were initially rather challenging as we experienced strong noise in the first data recordings. However, we were able to correct this handicap and ultimately were able to produce very good data.

For me, meeting Brandon was indeed "good luck" ("Glück-Auf") - not only because we worked very well together in this high altitude, but also enjoyed excellent conversations alongside the strenuous work. Brandon's comment after Day#2: “I didn’t expect that I would have to work so hard out here…”

However, at the end of Day#3 he also exclaimed with a hint of pride in his voice: “Now I have the confidence that I can carry out these NMR measurements on my own!” - “Of course you can. No problem!” was my succinct answer – with a smile on my face because it was exactly what I actually wanted to achieve (besides acquiring good data): that our client is enabled and empowered to carry out such measurements on their own in the future. That was the case in Peru, and now it happened also in Colorado.

Dito: Much learned, much more to be learned, and developing a viable “Roadside NMR Service” as a "quasi-blueprint" for a benefit provision to similar projects in Germany | Europe.

! Chapeau | Carpe Diem | Stay healthy !