The author as Pvt. John Collins
During the Summer of 2005, I slowly passed through Montana with a group of re-enactors who were retracing, day-by-day, the Lewis and Clark Expedition. The original expedition of captains Merriwether Lewis and William Clark with their Corps of Discovery were the first Americans to cross the continent by land. Their trip started in the Eastern U.S. in August of 1803 and finally finished back in St. Louis in September of 1806 after they successfully made it to the Pacific Ocean.
In the Spring and Summer months of 1805, the Corps of Discovery moved up the Missouri River through the territory that would one day be the state Montana. Just as the original expedition, the all volunteer Discovery Expedition of St. Charles moved up the Missouri by boat in the Summer of 2005 as part of the bicentennial commemoration of the original crew’s achievements.
Lewis and Clark had no idea what lay ahead. Part of their instructions from President Jefferson was to collect information and specimens of geology and economic minerals. The two captains never knew that Montana had valuable corundum deposits. Even though they passed through a major sapphire deposit in the gravels of the Missouri River near today’s Helena, Montana, they did not describe any finds. The native Americans were also unaware of the riches under their feet.
However, in the past 200 years, the corundum deposits in Montana have been well documented. Besides being interested in history and exploration, I am keen to visit any gem mining areas that are accessible. Studying gemology courses at AIGS in Bangkok and taking field trips to nearby sapphire mining areas taught me that it is possible to visit such places if the proper arrangements are made.
One of the highlights of the Expedition during the Summer of 2005 was passing through theUpper Missouri Breaks National Monument. The upper part of the Breaks starts upstream from Judith Landing. Judith Landing is located at the confluence of the Judith and Missouri Rivers. The Judith River was named by William Clark after the woman he would eventually marry after returning home.
The naming of the Judith River is a nice story in itself. For me though, I was more interested in a place far upstream along the Judith River. I dearly wanted to visit a place nearer the source of the Judith up in the Little Belt Mountains. This was a place that the Corps of Discovery never knew about. This special place is near Utica, Montana. It is none other than Yogo Gulch. The Yogo mine is the source of the finest of the American sapphires.
All through the Spring, as we slowly made our way across the state, I asked everyone I met if they knew how I could see the Yogo mine. Nearly everyone either did not know or told me that it was closed. Finally, one day after participating in the color guard during the dedication of the Ft. Peck Dinosaur Museum, I met someone from Lewistown, Montana; who said they could help.
The Expedition kept me too busy to visit the Yogo mine at that time. The mine is far from the Missouri and we stuck with the river. I would have to wait until we reached Ft. Benton and Great Falls. This is where the original Corps portaged their dugout canoes and other equipment eighteen miles overland. This ordeal would take an entire month. Our crew would remain stationary for the same period of time at nearly the same location.
For me, this would be an opportunity to explore the areas the Lewis and Clark missed. I was ready for a break from sleeping on boats or a tent every night and the once-a-week shower routine. Certainly, the Yogo mine was at the top of my list. Unfortunately, the June weather did not cooperate, and I was not able to go during that month.
My mother was traveling along with our Expedition, documenting our adventure on video. We decided to leave the expedition behind at Great Falls and head further west. The weather may have been too wet to visit the Yogo mine, but there are other corundum deposits to visit in Montana.
We first decided to visit Gem Mountain located along the West Fork of Rock Creek near Philipsburg. This mine is operated at a commercial level as well as for tourists. Even though I had previously visited mines in Thailand, Laos, and Cambodia; this was my first tourist sapphire mine. I only wanted to collect some rough stones as specimens. However, the mine had none to sell. I had to “mine” my own.
Gem Mountain
The sapphires here are eluvial and you wash them from the gravel. A prospective miner buys the ore by the bucket. This ore has already been concentrated but not salted. With your bucket, you are given a screen, tweezers, a film canister, and an instructor. There is a real technique to be learned in order to efficiently find your sapphires. Unfortunately for me, this involved a lot of cold water and I had no gloves.
You start by pouring some of your gravel onto the screen. Then you place the screen in the water and rock it vigorously back and fourth. This cleans the gravel and causes the larger rocks to move outwards. Then you rotate 90 degrees and repeat. After doing this a few times, you “float” the rocks by shaking the screen up and down in the water. When you “float” the stones, it is important to hold the screen level so that the gravel will form a circle with an “eye” of dense material in the center. This step really gave me some headaches as I had trouble shaking in a level fashion.
Washing the gravel
Finally, you take your screen out of the water and over to a table. Then you quickly and smoothly flip the screen upside down onto the table. If all goes well, the sapphires should be sitting on top of the pile in the center. All you have to do then is pluck them out with your tweezers and place them in your film canister.
Picking out the sapphires
My mother and I made a good team on this sapphire hunt. It was an overcast and cold day, so she was not interested in screening the gravel. However, she did spend considerable time looking through the screened material be sure we didn’t miss any sapphires. Just to be sure, I screened each batch of gravel twice. Usually we found some more stones on the second screening.
I kept buying buckets of gravel until I though I had enough samples and my bare fingers were too numb to screen. Once I was finished, I went inside and had my lot of rough analyzed to see what could be heat treated. The rough from Gem Mountain responds well to heat treatment, and nearly all stones from this location are treated.
Only about 25% of my stones qualified for treatment. These would be shipped to me after they had been cooked. Most of the Gem Mountain stones will turn to a blue similar to that of aquamarine or irradiated blue topaz upon heat treatment. There are also a few pink and red stones.
Gem Mountain sapphires
Unheated (left), Heated (right)
We had arrived at Gem Mountain not long after they had opened that morning. This allowed us enough time to drive back to Helena to visit friends. It was then that I learned just how close we were to the Spokane Bar Mine. The drive to the mine was less than thirty minutes. It seemed like a good opportunity to go since we would be heading to the West Coast the next day.
I called the mine to get directions and we set off. The Spokane Bar sapphires are found in alluvial sediment along the Missouri River (Lake Hauser). Like Gem Mountain, the mine produces commercial quantities of stones and is open to the public to try their luck. Just as before, ore concentrate is sold to tourist to screen on-site or they can take it home.
Again, I was looking for specimens from different locations around the state. When I purchased my bag of ore, I made sure that I did not get one of the salted bags. At the Spokane Bar Mine, the bag of ore is much bigger than the buckets from Gem Mountain. Therefore, I found myself still screening the gravel well after the closing time of the shop. The procedure for screening was just the same as Gem Mountain.
After finishing my bag of gravel, my mother and I decided that we had enough energy to head west. We would travel around Washington and Oregon for the next three weeks. We would return to Great Falls for the 4th of July celebration.
Upon our return to Montana at the beginning of July, we rejoined the Discovery Expedition of St. Charles for the Independence Day events. Once the celebration was over, we again took off on our own.
I wanted to revisit the Spokane Bar Mine to collect samples from the El Dorado bar. There were some bags of gravel concentrate available even though, I was told, that location is no longer open to the public. The previous visit just had not allowed me enough time to screen a bag of gravel from the two locations.
El Dorado Bar sapphires
The shop at the mine has many faceted stones available for purchase. These come in many different shades of blues, pinks, and yellows. Many of the blues are a similar color to those of Gem Mountain. I was told that most of the stones in the shop were unheated. I decided to buy a couple of samples to check later.
A few days later, I finally had been able to arrange a tour of the Yogo Mine. There is currently no commercial production at the mine, but many residents of nearby Sapphire Village have limited mining rights. I would be given a tour by one of these residents.
The claim holders from Sapphire Village are allowed to stake a small claim on certain areas of the dike itself, or in the tailings of the mine. We first visited the dike area that was being mined by claim holders. Part of the restrictions for the claim holders is that they can only use hand tools. Seeing these small operations really reminded me of what I had seen in Laos and Cambodia.
We approached some miners with caution since our guide did not recognize anyone that day. However, once we explained what we were doing, they were happy to show us around. I was able to crawl around in the pits and see the difference between the limestone and the igneous intrusion. This was an amazingly clear example of an igneous dike into surrounding sedimentary rock. The dike was only about twenty feet wide in this location.
Edge of the dke Small diggings A hand-dug pit
Most of the dike was a reddish rock that does not contain the sapphires. The paydirt is a gray lamprolite material. Once inside a pit, it was easy to see the veins of lamprolite within the surrounding red rock. I was told that both of these materials weather quickly, and removing the surface material at the beginning of each mining season is not too difficult.
Sapphire bearing lamprolite
Rough Yogos
The miners told us that most of the people working this area were enthusiasts, so they typically did not sell the stones they found. However, they were always happy to show off their finds and describe what others had found. With no commercial production, finding a fine Yogo sapphire is difficult and expensive.
Once we had our fill of the workings around these small claims, we headed over to the area of the original British mining operation. There we found some more villagers working the tailings piles below the holding ponds. We could also see some bits and pieces of the original flumes and other equipment.
Gadsden House English Cut
I was amazed to see that the Gadsden house remains intact and was actually in good shape. The house had been restored by the mine owners over the years. Behind the house, the original English Cut into the dike was clearly visible. I really felt lucky to be standing in front of the house after reading Yogo:The Great American Sapphire. There was so much interesting history at that site and I had finally been able to see it for myself.
References;
1. Spokane Bar Mine:www.sapphiremine.com
2. Gem Mountain: www.gemmtn.com
3. Voynick, S.M., 1985, Yogo: The Great American Sapphire. Mountain Press, Missoula, 215 pp
4. Discovery Expedition of St Charles: www.lewisandclark.net
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