By: Erik Ronald, PG
Mining Geology HQ
In this edition of the In a Nutshell series we examine borates. This important industrial mineral is only produced in a few locations globally but plays an important role in the modern world. This article introduces what borates are, summarizes the market, reviews the global production centers, provides a brief geological overview of major borate deposits, describes exploration considerations, and takes a look at the future outlook for the borate market.
What are Borates?
The term “borates” is used to describe the family of naturally occurring minerals that contain the element boron (B). Elemental B has the atomic number five and is classified as a metalloid. It is not found in nature in an elemental state but typically combines with oxygen to form boric oxide (B2O3) or with other elements to form inorganic salts.
There are 250 known borate minerals with 11 being extracted economically (Table 1). The most commercially important mineral types are sodium and calcium borates which make up over 90% of the global market. Most borate minerals are white, light gray, or colorless, relatively soft (2 – 4.5 Moh’s hardness) and have a specific gravity typically less than 2.5.
Table 1: Economically important borate minerals.
Global Borate Market
Borates have a long, rich history of mining, trade, and use in a multitude of uses. They can be found in everyday household objects along with specialty products as varied as magnets for wind turbines and bulletproof vests. Borates also play an important role as an essential nutrient for plant growth yet they are a main ingredient in some pesticides and wood treatment against insects. To state they have a wide application of use is an understatement.
Approximately 80% of global demand is driven by the glass, ceramics and agricultural sectors in the form of refined borates or boric acid (Figure 1).
Figure 1: Global use of borates by industry (courtesy of Eti Maden AS).
Market pricing is based on either B2O3 grade or boric acid concentration. Borate products have commanded robust pricing typically established via contract with no spot market trading of borates such as in the more traditional metal commodities like gold and copper. The average price for boric acid is currently between US$800-$1,000 per tonne with refined colemanite being US$600-800 per tonne (Stormcrow, 2015).
The outlook for borates continues to be positive and is driven by population growth, urbanization, increasing demand for insulation, rising agricultural nutrient demands, modern high-tech glass products and coatings (used in computers, LEDs, plasma screens, circuit boards and solar panels) and many other industrial manufacturing applications. Production of flat display panel glass, like that of LCD, is one of the major boron consuming areas with growing importance. Demand for boron products remains strong, both regionally and globally.
China is the largest consumer of borates (Figure 2) and demand is growing at a rate faster than the overall borate industry, albeit close to its own GDP growth rate, which is currently around 7%. Unlike many raw material commodities such as iron ore or coking coal, borate demand is more correlated to middle- and upper-class consumer products. This fact, combined with the shifting of the Chinese economy from a primary supplier of raw materials like steel toward high-end products, results in a bright future for borate demand. The U.S. is the second largest borate-consuming country; demand there is forecast to grow at a rate higher than GDP, driven by recovery in the U.S. housing market.
Figure 2: World consumption of boron minerals and chemicals in 2014 (IHS Market, 2015).
Borates are essential minerals but markets and demand have traditionally been difficult to predict. This is largely because of the relatively small number of producers and because production of boric acid and other boron compounds is energy-intensive thus highly sensitive to changes in energy and sulfuric acid prices, both required for refining of raw borate ore into final products.
Where to Find Borates
Borate deposits are primarily lacustrine in origin with minor production from marine basin and skarn-related mineralization. The world-class deposits occur in Cenozoic sedimentary sequences located in arid climates within tectonically active zones, particularly in extensional settings such as western Turkey, southwestern U.S., and the Andean deserts of South America (Figure 3).
Figure 3: Global distribution of major borate deposits. (Kistler and Helvacı, 1994).
Within these settings, borate deposits form in highly saline, shallow, enclosed lacustrine environments and in saline inland basins as evaporite deposits, commonly in association with trona, sodium sulfate, gypsum and salt. The source of the boron-rich fluids is likely subducted marine sediments rich in B. The B-rich magma and associated fluids are remobilized and transported via hydrothermal activity. The hydrothermal origin of most borate deposits explains the proximal association with epithermal metal occurrences and thermal hot springs.
Figure 4: Genetic geological model for borate deposit formation (Helvacı, 2015).
Most borate minerals readily dissolve in water so their ability to form large tonnage ore bodies is rare and requires a specific set of conditions both during and after formation. Preservation of large concentrations of a highly soluble mineral in an active tectonic area is difficult to say the least, thus the scarcity of world-class borate deposits globally.
In lacustrine deposits, borates occur as brines or stratigraphic layers interbedded with sand or clays and encapsulated in impermeable layers thus preserving the deposits. Borates occur in association with other evaporite type minerals such as halite, potash, soda ash, and lithium carbonate. Due to their low-temperature hydrothermal origins, deleterious elements associated with lacustrine deposits are arsenic, strontium, and cesium.
Smaller, commercially viable deposits occur in Eastern Europe and central Asia as marine-derived deposits primarily associated with salt and potash deposits. These types of borate deposits typically yield magnesium borates which are produced as by-products of potash mining such as in Kazakhstan. Another category of economically viable deposits are the metamorphosed non-marine evaporite borate deposits that yield low-grade magnesium borates. These Mg and Mg-Fe-borates are important domestic sources of borates for China (Pend and Palmer, 2017). Lastly, there are skarn-related borate deposits, associated with magnesium and iron ore that are mined in eastern Russia (Kistler and Helvacı, 1994).
World Borate Production
Global borate production in 2015 was ~3 Mt B2O3 or ~10 Mt mined borate ore (USGS, 2015). Annual production of borate ore by country is presented in Table 2.
Table 2: Annual production of borate ore by country (USGS with USA production estimated).
Summary of Major Borate Deposits
Table 3 provides a brief deposit summary of major global borate deposits. Production figures are estimated or not available in many cases as the majority of producing borate mines are privately held and do not release annual production or Mineral Resources & Ore Reserve data.
Table 3: Major Global Borate deposits. Deposits in yellow are current producers. (multiple sources).
When it comes to major borate deposits, everything starts with Turkey. Turkey is the world leader in borate production, refined products, and reserves, containing 72% of identified global reserves of borates (Helvacı, 2015). The main Turkish deposits are Kırka, Emet, Kestelek, and Bigadiç are controlled by the State-owned Eti Maden AS.
Each of the four Turkish deposits exhibit similar geological genesis as hydrothermally sourced, lacustrine borate deposits. Only Kırka contains sodium borates in the form of tincal while all other Turkish deposits are primarily calcium borates producing colemanite (Helvacı, 2015).
United States deposits are restricted to the Mojave and Sonoran Deserts of California, Nevada, and Arizona. The two producing U.S. borate mines are Rio Tinto’s Boron operations, which mines and refines borates from the Kramer Deposit in California’s Mojave Desert; and Searles Valley Minerals Inc. (owned by India’s Gujarat-based Nirma Ltd), which producing borates from subterranean brines at Searles Lake as a co-product with sodium carbonate (trona) and sodium sulfate.
Figure 5: World market share for refined borates (data from Eti Maden AS).
Production from the Kramer deposit by Rio Tinto in 2015 was 476 Kt of ore with 23 Mt of JORC compliant Ore Reserves (Rio Tinto, 2015). This deposit hosts tincal, kernite, and ulexite. Data on production and reserves for Searles Valley Minerals Inc. is difficult to approximate due to the parent company Nirma being a privately owned Indian corporation. Historic estimates place the total borate reserves at roughly 20 Mt.
Figure 6: Rio Tinto’s Boron Operations in southern California, USA (image courtesy of Rio Tinto Minerals).
In Chilé, Quiborax or Quimica e Industrial del Borax Ltda operates the country’s primary borate mine located at 4,250m elevation in Monumento Natural de Surire, a national park. This salar-type deposit produced 580 Kt of ulexite in 2015 with reserves estimated at 1.5 Mt of ulexite ore (USGS, 2015). Only a small portion of production is sold as ulexite with the majority being processed with sulfuric acid to produce a high purity boric acid.
Figure 7 Quiborax’s operation at Salar de Surire (image courtesy of Quiborax).
Argentina has consistently produced borates for more than 50 years but has taken a back seat to Turkey and the U.S. in the supply of refined borates. Currently, Orocobre Ltd operates Borax Argentina’s Tincalayu Mine, producing ~40 Kta of refined borate products with plans to expand ore production to ~120 Kta.
The Tincalayu deposit contains tincal with lesser amounts of ulexite and kernite hosted in Miocene sandy units deposited in a lacustrine environment. This deposit contains 6.5 Mt of Indicated and Inferred (JORC) Resources at 13.9% B2O3 (Orocobre web site, 2017).
Figure 8: Tincalayu Mine (image courtesy of Orocobre Ltd).
The Chinese borate districts of Gaotaigou, Zhuanmiao, and Wengquangou are part of a regional resource in the Liaoning and Jilin Provinces of northern China (Ping and Palmer, 2017). The deposits in these districts are exploited by over 100 small underground operations developed within a Paleoproterozoic greenschist-amphibolite grade metasedimentary sequence (Harben and Kuzvart, 1996). The host sequence, which is up to 800 m thick, comprises metasediments, metavolcanics and what were originally nonmarine evaporites extending for 300 km east-west. The primary borate ore produced is szaibelyite, a magnesium borate, which is then processed into borax or boric acid. Proven reserves from a number of deposits total more than 30 Mt of borates (USGS, 2015). These deposits currently yield around 160 Kta of borate ore.
Additional Chinese production includes various borate minerals produced from brines near the Qinghai-Tibet plateau. The Qinghai deposits are located at an elevation of approximately 4,000m and contain inter-related mineral groups including boron, lithium, and potassium mined from three playa lakes in the Qaidam Basin (Carpenter and Kistler, 2006).
How to Find Borate Deposits
If you’re exploring for borates, consider the following:
- The right rocks: Find a Cenozoic suite (the more recent the better) of non-marine, fine-grained sediments and tuffs in an arid environment with known historic hydrothermal activity. Existing hot springs and epithermal deposits in the area are a good sign you’re in the right neighborhood.
- Chemistry data: Soil, rock chip and groundwater geochemical surveys have proven successful in identifying prospective areas for borate occurrences. Pathfinders include: strontium, arsenic, and lithium, not to mention boron itself. In Asian borate skarn deposits, beryllium has been used successfully as a pathfinder.
- Remote sensing data such as Thematic Mapper (TM) bands can indicate the presence of ulexite in soils otherwise obscured by halite as is common in salar-type deposits. This method has proven effective in salars of South America in the late 1980s.
- Hunt in elephant country, just under cover: It’s probable there are proximal deposits in established districts that are under cover. As is common with major mining companies, once a multi-decade reserve has been identified, there is little appetite for continued exploration resulting in poor near mine exploration and prospects being under-explored or shelved indefinitely.
- Try somewhere new: Less explored regions of the globe such as central and western Asia, North and East Africa, Australia, and northwestern Mexico are likely areas for further investigation.
- Geophysics first, then drill: Gravity, magnetic, and seismic surveys won’t directly find borates but can provide indications of depth to basement, sedimentary sequence thickness, and most importantly structural information. These are all important aspects to understand the potential for the presence of a borate deposit.
Where will Future Production be Sourced?
Given Turkey’s ample borate reserves, we don’t need to worry about running out of borates anytime soon. Though there is sufficient supply for the foreseeable future, that supply is tightly controlled between a few companies, most of which are private. Any new production on the market would be of significant interest to investors.
- Near mine expansion – Western Turkey will continue to be the dominant player in borate supply globally with the ability to bring on new deposits in existing districts. Further expansion can be expected in southern California, pending environmental regulations. A significant hindrance is the governmental restrictive land-use as deposits with exploration potential are in or near National Parks, Monuments, and other areas with mining restrictions. Lastly, the salars of South America will continue to produce, though with declining grades.
- Re-start of historic mines – Historic mining in western China (Tibet), USA, Argentina, and Chilé will likely re-start if strong prices continue. Though the global demand is not expected to drastically increase in the near future, a small operation could gain market entry if prices remain competitive and product quality/consistency could be maintained. Though currently not producing, the Fort Cady deposit located in southern California is potentially a large-tonnage / low-grade colemanite deposit with low concentrations of deleterious elements. This deposit was briefly mined during the 1990s using in situ recovery (ISR) methods that initially yielded a high concentration boric acid with later production focused on calcium metaborate. The reserves at Fort Cady have been estimated as high as 147 Mt but the challenges of ISR forced the operation to close in the late 1990s.
- New mines – Rio Tinto is currently in the pre-feasibility stage of their Jadar lithium-borate deposit in Serbia. This deposit contains the rare mineral jaderite, a lithium borate that has the potential to produce both lithium carbonate and boric acid. The project is strategically placed at the backdoor of the European market. Other promising deposits such as the Magdalena deposit in Sonora, Mexico and the Piskanja deposit in Serbia are potential future producers that may be able to gain a small market share. Lastly, never discount domestic Chinese supply. As China is a major importer of borates, finding a reliable domestic source would be in China’s best interest and given the historic production from several provinces, we may see new operations come online.
One consideration that affects the feasibility of any new deposit is the close association of arsenic with borates. As environmental regulations become more stringent globally, the control and disposal of high-arsenic material becomes of greater concern for any new deposit trying to enter the market.
Borates are an important mineral group for modern society with demand expected to continue to grow at or above global GDP rates. There are few substitutes for borates especially in high-end applications and agriculture. These markets are expected to grow as global population grows and becomes more affluent.
Production, reserves, and to some extent pricing are controlled primarily by the Turkish State company Eti Maden AS and Rio Tinto Ltd with other companies contributing to global supply of refined borates. China will likely continue to be the primary market for borates with additional demand from the USA, EU, India, and other East Asian countries.
From an exploration perspective, borates tend to be a high-margin industry but the keys are B2O3 grade, minability, proximity to infrastructure, and arsenic concentrations. Low grade or costly mining such as underground methods can quickly erode margins not to mention high capital requirements for infrastructure investment. Additionally, any borate prospect must be assessed for arsenic as regulations become stricter with time.
From an investor point of view, borates are a bit tricky as there are no pure borate companies that are publically traded. Rio Tinto Ltd. is a public company but hardly a borate play as the U.S. – based Boron operations makes up about one percent of Rio’s annual earning. The closest to a pure play would be Orocobre Ltd., an Australian-based public company that operates the Borax Argentina operations. Orocobre is also focused on lithium production in South America but is highly exposed to the borate market and pricing.
There are several junior companies seeking to develop borate deposits globally that will likely prove difficult for myriad reasons, most commonly low grades and high arsenic.
Given the strong global demand for borates, robust pricing, and anticipated growth in demand for borates, it’s a wonder why more exploration companies aren’t hunting borates. Perhaps this will change and we’ll see borates follow in line with lithium and other “hot” commodities in the coming years as its use in technology increases as more applications are discovered.
I hope you enjoyed this in a nutshell summary of borates. For further reading and more detailed descriptions of deposit geology or applications for borates, I encourage you to read the papers listed in the references.
The author would like to acknowledge and sincerely thank Steven Carpenter and Cahit Helvacı for their review and comments on this article.
Brooker, M., 2014, Technical Report on the Tincalayu Borax Mine, Salta Province, Argentina prepared by Hydrominex Geoscience Consulting for NI43-101, Orocobre Ltd.
Carpenter, S. B. & Kistler, R. B., 2006, Boron and Borates: chapter in ed. Kogel, J. E.; 7th edition Industrial Minerals and Rocks: SME: pp. 275-283.
Eti Maden, 2013, Turkey as the Global Leader in Boron Export & Production – presentation for the European Association of Service Providers for Persons with Disabilities, Annual Conference, İstanbul, 2013.
Floyd, P.A, Helvacı, C, Mittwede, S.K., 1998, Geochemical discrimination of volcanic rocks, associated with borate deposits: an exproation tool. Journal of Geochemical Exploration 60, pp 185-205.
Garcia-Veigas, J. and Helvacı, C., 2013, Mineralogy and sedimentology of the Miocene Gocenoluk borate deposit, Kırka district, western Anatolia, Turkey. Sedimentary Geology 290, pp 85–96.
Harben, P. and Bates, R., 1990, Industrial Minerals Geology and World Deposits. Industrial Minerals Division, Metal Bulletin Plc, London, UK.
Harben, P. and Kuzvart, M., 1996, Industrial Minerals – A Global Geology, Industrial Minerals information Ltd. Metal Bulletin PLC, London, UK.
Helvacı, C., and Orti, F., 2004, Zoning in the Kirka Borate Deposit, Western Turkey: Primary Evaporitic Fractionation or Diagenetic Modifications? Canadian Mineralogist, Aug 2004, vol. 42, No. 4, pp 1179-1204.
Helvacı, C., 2015, Geological Features of Neogene Basins Hosting Borate Deposits: An Overview of Deposit and Future Forecast, Turkey. Bull. Min. Res. Exp., 151: pp 169-215.
Helvacı, C. 2012, Trip to Kışladağ (Uşak) Gold Mine, Kırka and Emet Borates Deposits. Post Colloquium Field Trip Guide Book. International Earth Sciences Colloquium on the Agean Region, IESCA 2012, İzmir, Turkey, pp 41.
Helvacı C., 1995, Stratigraphy, mineralogy, and genesis of the Bigadic Borate deposits, western Turkey. Economic Geology, vol. 90, pp 1237-1260.
Helvacı, C. and Orti, F., 1998, Sedimentology and diagenesis of Miocene colemanite-ulexite deposits (western Anatolia, Turkey). Journal of Sedimentary Research 68: pp 1021-1033.
Helvacı, C. and Alonso, R.N., 2000, Borate deposits of Turkey and Argentina: a summary and geological comparison, Turkish Journal of Earth Sciences 24, pp 1-27.
Helvacı, C. and Firman, R.J., 1976, Geological setting and mineralogy of Emet borate deposit, Turkey, Transactions/section B, Institute of Mining and Metallurgy 85, pp 142-152.
IHS Markit, 2005, Chemical Economics Handbook: Boron Minerals and Chemicals. https://www.ihs.com/products/boron-minerals-chemical-economics-handbook.html
Kistler, R. and Helvacı, C., 1994, Boron and Borates in Industrial Minerals and Rocks, Society of Mining, Metallurgy, and Exploration.
Lyday, P., 2000, Boron, U.S. Geological Survey Mineral Resource Program, publication 120401.
Peng, Q-M. and Palmer, M. R., 2002, The Paleoproterozoic Mg and Mg-Fe Borate deposits of Liaoning and Jilin Provinces, northeast China: in Economic Geology, vol. 97, pp 93-108.
Rio Tinto Limited, 2015, Annual Report 2015, Available at: http://www.riotinto.com/investors/annual-report-2015-16577.aspx
Stormcrow, 2015, Borates Industry Report. Available at: http://www.stormcrow.ca.