U.S. Borax Operations

Pioneering Progress

We are a global leader in industrial mineral supply and science. We provide approximately 30% of the world’s supply of refined borates—remarkable minerals that are essential to life and to modern living—from our world-class Rio Tinto U.S. Borax mine in Boron, California, about 100 miles east of Los Angeles. As part of Rio Tinto , an international mining and resources company, we serve more than 500 customers in 1,700 locations across 100 countries. Our customers rely on boron and borates to create an extraordinarily diverse range of borate products.

We have more than 30 industrial, agriculture, and specialty products that are sold under the iconic 20 Mule Team® Borax brand, known worldwide for its quality and American Old West heritage.

Rio Tinto Borax mine

U.S. Borax Operations Today

U.S. Borax is acknowledged as the world leader in borate technology, research, and development. Technical support for customers, product quality, and supply reliability are the pillars of our commercial commitment.

As a global leader in industrial mineral supply and science—operates mining, refining, and shipping facilities on four continents, U.S. Borax distinguishes itself through:

  • Cutting-edge research and development
  • World-class safety, environmental, and community practices
  • A commitment to constant innovation and improvement

We maintain a global network of sales offices and stock points. Our researchers work to advance borate science while pioneering new products and applications that harness the many properties of boron.

Sustainable Development

Sustainable Development

Our commitment to protecting the environment dates back to the early days of U.S. Borax. Back in 1916, company officials helped write the language that was adopted by U.S. Congress to establish the National Park Service. Today, we continue that commitment to ensuring that our practices and products are socially, environmentally, and economically sustainable.

  • Land and water
  • Wildlife
  • Energy and waste reduction

Learn more about our sustainable development  ›


The heart of U.S. Borax is the open-pit mine in Boron, California, one of two world-class borate deposits on the planet. What began as an underground mine in 1872 is now California’s largest open pit mine and one of the richest borate deposits on the planet. In California, U.S. Borax operates its principal mine and refinery in Boron, a refinery and shipping terminal in the Port of Los Angeles, and a trona mine in Owens Lake. Learn more about our operations in California:

Our worldwide organization also includes a distribution and packaging facility in Rotterdam, the Netherlands; a refinery and distribution facility in Coudekerque, France; a packaging and distribution facility in Nules, Spain; and sales and customer service centers around the world. Rio Tinto also has a development site in Jadar, Serbia.


Rio Tinto Borates Careers

Careers with U.S. Borax

Looking for a career that matters, with a company that cares?

Join U.S. Borax and help us achieve our mission: Supplying the world with refined borates, remarkable minerals that are essential to human progress and modern living.

Explore careers with us  ›


Commitment to Our Communities

We prioritize commitment to our communities—both those that we operate in and those that we serve. In Boron, California—our home since 1872—we maintain the historic Borax Visitor Center, which has welcomed more than 125,000 visitors. Our company also teams with area leaders to support local nonprofit organizations through the Borax Visitor Center Foundation. And we encourage all our employees to take an active role as volunteers within their home communities.


U.S. Borax traces its roots to California’s Death Valley, where borate deposits were discovered in 1872. The mule teams that hauled borates out of our original mines in Death Valley are long gone, but the symbol endures in the 20 Mule Team® Borax brand. In the marketplace, this brand is the mark of exceptional reliability, quality, support, and service. Today, U.S. Borax is acknowledged as the world leader in borate technology, research, and development.

The 20 Mule Team rode in the Rose Parade with brand new replica wagons, 100 years after their first appearance, remaining an icon of history and perseverance in California, and across the U.S.
Watch the video
The safety award-winning Modified Direct Dissolving of Kernite (MDDK) process facility opened at Boron operations, maximizing the utilization of the ore body in order to meet marketing demands, increasing mine yield by approximately 6-8%
Donated more land to expand Death Valley National Park
Changshu, China distribution center opened
Granubor® 2 developed for agriculture
Lithium-borate deposit discovered in Serbia
Global operations achieved ISO 9001 certification for excellence in Quality Management
Chrysler Natrium, world's first sodium borohydride-powered, zero emission vehicle made pit stop at U.S. Borax's Boron Operations
Company formed partnership with Millennium Cell to develop safe, clean fuel alternative based on sodium borohydride
Global operations achieved ISO 14000 certification for excellence in environmental management
Twenty Mule Team's last ride with original wagons in Pasadena Rose Parade
Polybor® Flow liquid borate invented;
New sales offices established in China
Company celebrated 125th anniversary; Borax Visitor Center opened in Boron, California
Global operations achieved ISO 9002 certification for excellence in Quality Management
Firebrake® 500, anhydrous zinc borate, developed
Donated land and lobbied the U.S. government to create Death Valley National Park
Solubor®, an agriculture micronutrient, invented
Boraxo, Borateem, and 20 Mule Team product lines sold to Dial Corporation
Boric acid plant built at Boron Operations in California
Borax acquired by Rio Tinto
Late 1950s
Boron Operations converted to a surface mine, extensive refining facilities built
Donated land to the U.S. government to create Death Valley National Monument
Underground mine opened at current mine location in Boron, California
Boron deposit discovered at current location
Wilmington, California refinery built
Borax España refinery constructed in Barcelona
20 Mule Team rode in the Rose Parade, carrying the parade’s president, and representing U.S. Borax as a national symbol of perseverance
Helped write the language adopted by the U.S. Congress to establish the National Park Service
Twenty mule teams begin to haul borates
Borates discovered in Death Valley
Company founder F.M. "Borax" Smith discovered borates in Nevada
Load More

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 500 customers with more than 1,700 delivery locations globally. We supply 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles east of Los Angeles.  Learn more about Rio Tinto

Copyright © 2019 Rio Tinto. All Rights Reserved.