Sapphire Production at Montana’s Historic Mine
In part two of Gems & Jewellery Magazine’s interview with Jerod Edington, interim president of Yogold USA, Olga Gonzalez FGA DGA and Founder of Pietra Communications, finds about current activity, and what is in store for the Yogo deposit.
Yogo sapphires are unique amongst the corundum family. From their pioneer-era roots, the gemstones have attracted prospectors and geologists and captured the fascination of the world. Emerging as sparkling-blue pebbles from the Yogo Gulch area of Montana, Yogo sapphires are renowned for their exceptional colour- the cornflower-blue gemstones are particularly desirable. While sapphires from other localities often display colour zoning, or a change in colour distribution, the colour of the Yogo material remains consistent throughout the stone. While heat treatment of sapphires in the market is common, with most using it to remove the colour zoning and improve clarity, Yogo sapphires are never heat treated, since the stones are mostly free of silk and have relatively few inclusions. Additionally, Yogo gemstones shine brilliantly in both daylight and artificial light. The sublime geology of this part of Montana has gifted the world with a truly transcendent gem.
After forty years, the historic deposit, including the entire five-mile-long sapphire-bearing dike, is undergoing a renaissance. The Yogo mine is back in production, with Yogold USA at the helm. This family-owned business has the support of over five hundred combined years of industry expertise in their Yogo endeavour. Underground rehabilitation was initiated on 23 February of this year. These efforts will result in greater production and thus an unprecedented opportunity to own, collect and wear one of these precious gems. In the second part of our two-part series on Yogo sapphires, Yogold USA’s interim president, Jerod Edington, discusses all these exciting new developments (for part one, please refer to Winter 2021 G&J, pp. 18-19).
Can you describe the excavation and concentration of corundum in the Yogo dike, undertaken since Yogold USA became the operator?
JE: The last two mining seasons were focused on mining the Yogo dike where it is exposed on the surface. Mining the surface material was fundamental; we used a large excavator and a 12-yard diesel dump truck. The excavation and transportation of the ore from the mining area to the processing plant has an average cycle time of about forty-five minutes. Therefore, we typically mined and hauled twelve payloads in a 10-hour shift.
As with most gem deposits, the concentration of corundum varies in different sections of the dike. The ultramafic dike was infused along a shear zone or fault. In some areas, the fault created brecciate zones that are quite wide. The wide zones have natural dilution due to the host rock being in fragments. In other areas, the Yogo dike is very well defined on both the hanging wall and footwall. Because these sections of dike are narrower, and typically range from six feet to eight feet in width, they generally contain a higher number of carats per ton, because of less wall-rock dilution.
What is the anticipated timeline to begin underground mining?
JE: This past fall, we constructed a new steel and concrete portal that meets specifications of the Mine Safety and Health Administration (MSHA) regulations. This included adding extensive rock-bolting and screening to the side of the mountain above the mine entrance. Because we plan to store explosives underground, we contracted the fabrication of a steel plate door for security purposes.We received a letter of authorisation from MSHA to initiate underground operations on 21 March 2021. We removed a known caved area set back about 150 feet from the entrance of the Kunisaki haulage tunnel, which was driven in the mid-1970s by Chikara Kunisaki and is 3,000 ft. (914.4 meters) in length. Pursuant to discussions with several miners that worked the Yogo Gulch deposit as young men in different capacities back in the mid-1970s, and predicated upon historical maps we obtained, we learned that there are large sections of unmined sapphire bearing dike starting back about 900 ft. (274.3 m) from the entrance. We have commenced rehabilitating the primary haulage way. Next, we plan to establish secondary escape ways; run air, water and electricity back into the haulage tunnel; we will then initiate activity utilising the shrinkage-stoping mining technique. Having access to and being able to rehabilitate this primary haulage way will provide substantial financial savings, and reduce the time needed to bring the underground portion of the mine back into production.
Our mining engineer and outside consultants, who are familiar with mining narrow structures, have designed a plan that has an initial production target of 150 tons (136 metric tons) per day. The mining plan is being developed and finalised using Vulcan 3D Software, developed by Maptek out of Colorado. When complete, the plan will include three-dimensional geological modelling and digital mapping. It will create the overall mine design and define production planning. Using Vulcan software will assist with evaluating and maintaining daily operational information, while taking economic, technical and operational outcomes into account. Assuming we do not run into unusual circumstances, we hope to start underground production around
1 May of this year.
Can you discuss your company’s work in maintaining Yogo Creek? Why is preservation important, and what steps has Yogold USA taken to maintain it?
JE: Yogo Creek is currently restored. Yogold’s priority is to maintain the creek and surrounding area to keep it in pristine and natural condition. This is important to protect fish and wildlife that are dependent on the creek. A section of Yogo Creek bisects our property; this section is home to twelve beaver ponds.
As a matter of policy, we do not engage in any mining, or any kind of disturbance, within fifty feet of the creek bank. We have a couple of locations where the historic road was constructed over a hundred years ago, running adjacent and parallel to the creek. In some areas, we widened the road away from the creek, and constructed earth berms to prevent access to the creek by a vehicle, equipment or floodwaters from a side canyon or coulees (due to flash floods which take place from time to time).
In the spring of 2021, we made the decision to replace an ancient log bridge across Yogo Creek that was in very bad repair. To remove and replace this bridge, we had to make concurrent applications and get approval from three government agencies: the Judith Basis Conservation District; the State of Montana, Department of Fish, Wildlife and Park; and the State of Montana, Department of Environmental Quality. We filed applications and submitted engineering drawings to all three agencies for constructing a 16 ft. by 50 ft. steel bridge and were subsequently granted permits. The construction process and equipment used to install the steel bridge was selected to reduce the risk of any damage to the stream bottom, to minimise erosion, to avoid the creation of sedimentation or turbidity and to ensure that there was no sloughing of the banks into the water or rechannelling of the stream. Yogold accomplished these objectives, and all three agencies approved the finished bridge.
Your company is funding a cutting facility in Sri Lanka. What is the turnaround for moving goods there and back? How has this helped your business, and is this Yogold’s model moving forward?
JE: We were extremely fortunate to have met Mr Amitha Gamage, who manages the cutting facility and brings tremendous expertise and experience as a member of our board of directors. He held the position of chairman and CEO of the Sri Lanka National Gem and Jewelry Authority from 2013 to 2015 and during 2020. He established Amaran Gems Pvt. Ltd. in 1991, which specialises in providing high-quality gems and designer jewellery to clients globally. In addition, he is the owner of Amaran Gemlab Pvt. Ltd., a company that authenticates gemstones using testing such as Fourier-transform infrared (FTIR), ultraviolet/visible/near-infra red (UV-Vis-NIR) and photoluminescence (PL) spectroscopy. These methods are used to identify gemstone species and variety, natural or synthetic origins and treatments; they are also used for colour grading. Mr Gamage is also conducting a feasibility study related to the expansion of the cutting facility to include the manufacturing of fine jewellery.
It is very beneficial for Yogold USA to have developed the facility in Sri Lanka. Whereas contract cutting facilities often focus on speed and volume, quality is at the forefront of this operation. The overhead costs are more favourable in Sri Lanka, and Yogo sapphires are the only stones being cut there; therefore, Yogo sapphires are the priority. Unlike with a custom order, there is no waiting in line.
Typically, Yogold USA ships parcels of rough out every 5-7 business days. The rough material generally arrives in three days and clears Sri Lankan customs 2-3 days later. The cutting and polishing require 5-6 days, and then it takes another five days to deliver back to one of our U.S. offices. On the average, the cycle time ranges from 15 to 17 days.
Is Yogold USA planning to give back to the local community in Sri Lanka, where the sapphires are cut? If so, how?
JE: Thank you for asking this question. We have already formed a 501(c)(3) nonprofit and tax-exempt corporation called the Yogo Global Help Foundation, which will be administered by Mr Gamage. The Yogo Global Help Foundation is working with Sabaragamuwa University of Sri Lanka (SUSL), which is in the process of expanding its curriculum to include a diploma in gemmology. While serving during his 2020 term as chairman of the Gem Authority of Sri Lanka, Mr Gamage had discussions with government officials about starting such a program.
SUSL is in the city of Belihuloya, but it also falls under the administration of Ratnapura District; Ratnapura is the gem mining and cutting capital of the country. There are many gem miners residing in the Ratnapura area who engage in high risk mining and who are generally on the lower end of the economic scale. Once the two-year program is established (currently slated for June 2022), Yogold will contribute money from each stone cut in Sri Lanka towards a scholarship fund. This scholarship program will allow children from gem mining families and communities to attend the gemmology program at SUSL themselves.
Another area that our non-profit will support is scholarships for children and families pursuing an education in jewellery craftsmanship. In Sri Lanka, cutting methods and knowledge are passed down from generation to generation, but in today’s world there is a need to boost hands-on experience with formal education. For this reason, we are developing scholarships to help young people obtain a diploma in jewellery manufacturing and design.
Speaking of cutting, because of the tabular shape of many of the corundum crystals derived from your mine, I understand that you are evaluating some unique and innovative cutting techniques related to concave faceting. Can you tell us about your plans?
JE: Historically speaking, the Yogo mine produced a large percentage of tabular crystals that are not the optimum for standard faceting. Through discussions with some very well-known master fantasy cutters, we know that ideally the rough should have one flat side, with a thickness that ranges from 2.8 to 3.6 mm. Based on this information, we are test-cutting a dozen sapphires that weigh over six carats.
The Yogo sapphires are already brilliant when traditionally cut. Due to the uniform colouring of our rough – particularly the beautiful and natural cornflower-blue colour that is associated with Yogo material – concave cutting, which involves creative use of refracted light through a gemstone and forms dynamic and unusual effects, should produce maximum brilliance. We are very excited to see how our Yogo sapphires turn out. We have ordered two complete fantasy cutting systems, which are being delivered to our cutting facility in Colombo, Sri Lanka.
In anticipation of our expansion into fantasy cutting, and because of a long and established relationship, Mr Gamage was able to have award-winning lapidary Mr I.M.N. Jayantha llangakoon come out of retirement for a six-month consulting arrangement. From 1986 until his retirement in 2009, Mr llangakoon was employed as a lapidary and gem-carving training officer in the National Gem and Jewelry Research and Training Institute. Amongst the many awards he won during his career, Mr llangakoon received Sri Lanka’s Presidential Award for Gem Carving in 2018. Mr llangakoon will assist with the set-up of the expanded operation and will train several already seasoned cutters.
About how much of the rough you are excavating is violet, and what is the value difference between the violet, colourchange and blue sapphire rough?
JE: The percentage of violet and purple sapphire varies at different locations along the dike. In some areas, the purple sapphires are as high as 3% of the yield, and in other areas it drops down to less than 1%. We also have a small percentage of sapphires that are referred to as ‘colour changers’; they change colour depending on light to which they are subjected. In daylight and fluorescent light, these samples are typically blue to blue-violet, but with incandescent light, they range from purple to reddish purple or, rarely, red. This is a unique characteristic, and due to this distinct property and their rarity these colour-change sapphires have a substantially greater value, priced 15%-20% higher than their natural cornflower-blue counterparts.
How are Yogo sapphires priced differently from heat-treated, colour-zoned material found elsewhere? Can you share any figures?
JE: By their very nature Yogo sapphires do not require any enhancement, and therefore they are marketed in a different category than fancy-coloured sapphires mined from alluvial deposits here in the state of Montana, and sapphires from other locations around the world. Yogo sapphires are comparable in price to other fine-quality, natural sapphires currently mined on a very limited scale from alluvial deposits in other locations in Asia.
How do you promote trust and transparency within your business model at Yogold USA?
JE: In thinking about trust and transparency, our stance at Yogold USA is fundamental and simple. Talk is cheap and does not create trust. Rather, our actions – being ethical, reasonable and truthful, and by fulfilment of statements and representation we have made and will make in the future – is what will lead to a growing trust and ultimately define Yogold’s reputation and brand within the industry.
To learn more about Yogold USA, visit https://www.yogoldusa.com/.
