Timeline for Bonneville Salt Flats: Racing, Mining, Science, Legislation

Below is a historical snapshot of what has occurred out on the Bonneville Salt Flats over the last century. It looks at motorsports, mining, scientific and engineering studies, federal land management and legislative actions. The salt speedway is in trouble. While some insist remedial action is being taken to spin a positive outlook, the bigger, long-term picture remains bleak.

What remains gloriously intact for more than 11,ooo years has been virtually decimated in less than a century. Many factors are in play. Bonneville, as Hemingway once remarked, is a “movable feast.”

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Bonneville Salt Flats Timeline

The Bonneville Salt Flats (BSF) were originally called “The Salduro Marsh.” Salduro means “hard or rock hard salt.” Geologists describe the salt flats as centered in a bowl shaped area rich in concentrated minerals and underlying heavy carbonate mud. Based on the length, width and depth described in historical reports, the area under the five foot plus salt crust can be described as a “shallow dinner plate.”

This is critical to understanding the area’s salt loss and surface crust quality problems created by human interference throughout the past 100 years. The 1% annual loss of salt crust exposes a progressively enlarging mud around the perimeter. This increases dust pollution and rain erosion mud transfers onto the salt crust.

Prior to the 1900s, Bonneville’s crust was unobstructed from Wendover, 80 miles east to Knolls and stretched some 100 miles to the south. Australia’s Lake Gairdner of present day mirrors Bonneville’s past condition.


Ill-fated Donner-Reed party crosses the BSF on the way to  California. Wagon tracks can still be seen on the edges of the BSF.


G. K. Gilbert publishes “Lake Bonneville: U.S. Geological Survey” May 1, 1890. Carpenter, Everett, Ground water in Box Elder and Tooele Counties, Utah


Bill Rishel becomes first man to cross the salt flats on a bicycle in a 3,000-mile coast-to-coast race. A.L. Westward of the National Trails Association, declares BSF “the greatest speedway on earth.”


Western Pacific Railroad line constructed through Bonneville Salt Flats. This westward rail expansion pierced the Salduro Marsh dead center towards Wendover. Records and studies of the work performed cite numerous difficulties encountered in constructing the railroad due to the salt flats thickness and hardness.


Mining begins in the area with a team of horses and a single plow blade. The town of Salduro was at the center of the thickest section of the salt crust.


Future Salt Lake City Mayor, Ab Jenkins became the first person to ride a motorized vehicle across the salt flats on his motorcycle.


Doc: U.S. Geological  Survey Water-Supply Paper 333, 1913.


First unofficial world land speed record set at the BSF by Teddy Tetzlaff. Tetzlaff remarked on the smoothness of the salt and how the coolness of the salt surface did not overheat tires. Top tire companies began testing tires on the BSF by sponsoring events. Utah Governor William Spry was on hand to watch Tetlaff’s racing and rode with Tetzlaff in the record-setting car on the flats.

Chicago: “The Railway Age Gazette” pronounces “this natural racing-track is a level bed of salt, 98 % pure…The salt-beds are 65 miles long and 8 miles wide. The estimated depth, in the middle, is 12 – 15 feet.”


First recorded destruction of BSF. Salt Lake Tribune, Sept. 12, 1915 article: “Mighty Bed Of Salt Being Scooped Up For Use Of Mankind.” Opening paragraph states, “The world’s greatest natural speedway is being torn up and ground up and dispensed to the public in cartons and packages…,The largest deposit of pure salt yet discovered is being marred, is disappearing…,The saline deposit covers a surface area approximately sixty-five miles long and twenty-five miles wide.”


Doc:  Anonymous, Potash in the lake muds of western Utah: U.S. Geol. Survey Press Bulletin 271, May, 1916. Gale, H.S., Potash in Salduro salt deposits: Eng. and Min. Jour., vol. 102 pp. 780-82 , Oct. 23, 1916


Utah-Salduro Company (subsidiary of Solvay Process Co.) begins harvesting minerals from the BSF for potash production

Doc: Gale, H.S., Potash in 1916: U.S. Geol. Survey Mineral Resources, 1916, pt 2, pp. 98 – 100, 1917


Brine collection ditch dug at Salduro Loop, spoil from the ditches piled up to construct the dike around Salduro Loop.

These ditches would later be abandoned, leaving mud tailings within just feet of the historical speed and endurance racetrack that would, through wind and water erosion, begin to infiltrate salt crust.


Congress gives 40 sq. miles to The Bonneville Corporation. Combined with the 49 sq. miles acquired from the Utah-Salduro Co., the mingin company now has a total 57,500 acres.


Victory Highway (Highway 40) constructed through BSF. Future mayor of Salt Lake City, Ab Jenkins, raced a train from Salt Lake City to Wendover and won as part of celebration.


Study: Thomas B. Nolan, Potash Brines in the Great Salt Lake Desert, Utah, U.S. Geological Survey Bulletin 795-B. “The salt is reported to reach a maximum thickness of 5 feet near the central portion of the deposit. The greatest amount found during boring, however, was 3 1/2 feet near Salduro station. From the maximum it thins rather gradually to zero at the edge.”

1933 – 1957

Ab Jenkins begins his triple decade career of setting 56 AAA Contest Board National Speed and Endurance Records on BSF. Hundreds of records would follow.


First Internationally recognized World Land Speed Record set at BSF by Britain’s Sir Malcolm Campbell; new record prompts international land speed racing community to relocate all future efforts from Daytona Beach, Florida to the BSF. Ab Jenkins was directly responsible for epic shift.

Britain’s John Cobb sets 24-hour endurance  and  21 additional world speed records inside a week on the BSF. Jenkins, now Salt Lake City mayor, sets a land speed record on a Allis-Chalmers tractor.


Bonneville Ltd. acquires Salduro mining operation and revives potash production.

Ab Jenkins, SLC mayor, driving his “Mormon Meteor” designed by Augie Duesenberg, sets 72 records, some of which would stand for nearly 50 years.


Bureau of Land Management (BLM) becomes custodian of the BSF


Britain’s John Cobb runs his 400 mph race car on BSF as part of Utah’s Centennial. The official program declares “The salt is like concrete. Bonneville is the world’s finest race course for several reasons. Its extreme hardness gives speeding cars maximum traction…” 


First “Bonneville National Speed Trials” (precursor to modern “Speed Week”) held at the BSF


General Motors names its all–new 1957 Pontiac model “Bonneville” after Ab and Marvin Jenkins set every American records possible with new car.


Federal government issues potassium leases covering 24,699.83 acres on the BSF to Bonneville Ltd.; leases cover area north of the highway and just east of the BSF race tracks; collection ditches dug on leases to allow for withdrawal of salt brine for potash production


Kaiser Aluminum and Chemical Corp. acquires potash mining operation


Kaiser requests permission from U.S. Geological Survey (USGS) to begin pumping from the collection ditches north of Hwy 40 into the potash mining operation


Mining company abandons Salduro Loop ditch

Early 1960s-1970s

Racers began noticing a problem with the salt crust

Late 1960s-1970s

Studies undertaken Utah Geological and Mineralogical Survey and the U.S. Geological Survey to determine extent of salt loss at the BSF

1963 – 1970

Craig Breedlove driving “Spirit of America,” Art Arfons, Driving “Green Monster” and Gary Gabelich driving “The Blue Flame” focus worldwide attention on BSF driving handbuilt jet and rocket-powered cars that reclaiming World Land Speed Record from the British. From 407MPH, the Americans raised the bar to 622MPH.


Interstate 80 constructed across the BSF replacing Hwy 40


Hydrogeology of BSF studied by Utah Geological and Mineral Survey; study notes that brine under the salt flats is “collected by a system of ditches and transferred to solar evaporation ponds where potassium chloride salts are precipitated and harvested…”  and that “shallow brine aquifer is the uppermost 25 feet of lacustrine sediments.  Because the brine is harvested for its potash content, it has been explored in more detail than the rest of the hydrologic system.”


Utah Geological and Mineral Survey conducts study comparing salt crust thickness in July 1960 to October 1974 and determines there was a 100% decrease in cubic yards of salt crust over 4 feet thick during that time period


Bonneville Salt Flats Race Track added to National Register of Historic Places


U.S. Geological Survey and BLM study “Hydrology and Surface Morphology of the Bonneville Salt Flats and Pilot Valley Playa, Utah”; study concludes: “Weather cycles may partly explain changes on the Bonneville salt crust. But the activities of man, such as withdrawing brine and constructing surface-drainage barriers, have altered the hydrologic environment and have had a profound effect on the salt crust. Water-level data indicate that during 1976 brine was moving through the shallow-brine aquifer on the Salt Flats from the area of salt crust toward all areas of manmade discharge (brine-collection ditches east and south of the salt crust and alluvial-fan wells west of the salt crust).” Study added: “Elimination of brine withdrawals from the ditch system north of the interstate highway would eliminate a yearly loss of about 680 acre-feet of brine and 270,000 tons of salt.”


Britain’s Richard Noble abandons BSF for Nevada’s Black Rock Desert due to reduced length of the salt’s international speedway. This removes BSF as the absolute world record-setting site. Noble sets 633MPH record on Black Rock.


30,203 acres of the BSF designated as Area of Critical Environmental Concern and identified as the Bonneville Salt Flats Special Recreation Management Area


Rick Vesco documents photographically massive amounts of mud sloughing off the mining tailings next to the raceway installed by the mining operations. He also noted water being drawn off the surface of the salt flats into the NE collection ponds 17 miles in length.


Reilly Industries, Inc. acquires potash mining operation


BLM Recreational Lands Manager, Gregg Morgan ESPN interview notes, “We are concerned with the loss of salt on the perimeter and with the overall loss. The study we completed a year ago, which updates the one we did 14 years ago shows that we are losing 1% of salt from the surface each year. That amounts to 1.6 million tons annually. At that rate, in ten years possibly there will not be enough salt to race on and in thirty years not enough salt to sustain what we call the Bonneville Salt Flats.”     

Save the Salt  (STS), is founded by racers, businesses and community members. Save The Salt Foundation is a nonprofit organization whose mission is to protect the Bonneville Salt Flats in Utah and to promote its history and motorsports legacy. The organization aspires to keep this national treasure available for future generations. 


After years of warning the BLM that conditions at the BSF are deteriorating, the racing community is apoplectic about poor conditions and continued salt loss; racers approach Congress in an attempt to force the BLM to take action


S. 1184 introduced on May 24, 1991 by Sen. Jake Garn (R-UT) and Sen. Orrin Hatch (R-UT) to require Sec. of Interior to conduct a study to determine the nature and extent of the salt loss from the salt flat crust occurring at Bonneville Salt Flats, Utah and authorizes appropriations for same; H.R. 1727 introduced on April 11, 1991 by Rep. James Hansen (R-UT) to require Sec. of Interior to conduct a study to determine the nature and extent of the salt loss from the salt flat crust occurring at Bonneville Salt Flats, Utah; H.R. 1096 amended on July 23, 1991 by Rep. Wayne Owens (D-UT) to require Sec. of Interior to conduct a study to determine the nature and extent of the salt loss from the salt flat crust occurring at Bonneville Salt Flats, Utah


Due to shrinkage, the available speedway lengths force Bonneville Nationals, Speed Week officials, to change international timing procedures. No longer could they support the required two-way runs within an hour and concentrated on only setting national records.

 Public Land Order 6941 withdraws 30,203 acres of the BSF from surface entry and mining for period of 20 years, but does not impact the federal mineral leases


H.R. 1603 introduced on April 1, 1993 by Rep. Bruce Vento (D-MN) to authorize appropriations for BLM for fiscal years 1994-97 and require Sec. of Interior to conduct a study to determine the nature and extent of the salt loss from the salt flat crust occurring at BSF, Utah


Racing community, mine owner Reilly, the BLM and the state of Utah negotiate a voluntary agreement to restore the BSF whereby Reilly will pump salt brine back onto the BSF during the winter months for five years beginning in 1997


Reilly begins pumping salt brine onto the BSF under voluntary salt laydown project. Independent testing of salt brine and surface samples reveal consistency is excellent for supporting racing vehicles.


U.S. Geological Survey entitled “Investigation of Salt Loss from the Bonneville Salt Flats, Northwestern Utah” explains, “maximum salt-crust thickness was 7 feet in 1960 and 5.5 feet in 1988.”  Study concludes, “with an estimated net loss of salt from the shallow-brine aquifer, the dissolved-solids concentration must be maintained by dissolution of the salt crust.”


Voluntary pumping agreement expires but Reilly chooses to continue pumping operation


BLM Professional Geologist W.W. White III evaluates success of the voluntary pumping program: “The 2-inch increase to salt-crust thickness expected as a result of the project was not observed in measurements from recent test pits and auger holes excavated in BSF….excepting contribution to the new salt-crust area, most of the 6.2 million tons of salt transported to BSF was apparently incorporated into the underlying shallow-brine aquifer.”

White also notes: “The capability of the shallow-brine aquifer to accept additional NaCl is significant, because it is the shallow-brine aquifer that regulates the distribution of NaCl mass to the BSF salt crust. If the Laydown NaCl mass is assimilated by the shallow-brine aquifer, then: 1) one would anticipate an increase of NaCl concentration in the affected area of the shallow-brine aquifer, and 2) it would not be unreasonable to expect that more halite mass would be added to the existing salt crust as a result of this increased NaCl concentration.”


Intrepid Potash, Inc. acquires potash mining operation from Reilly; BLM and the Utah Division of Oil, Gas and Mining request Intrepid submit a new mining plan


Intrepid submits draft mining plan; BLM denies racing community the opportunity to participate in reviewing/commenting on the mining plan.


Intrepid and BLM prepare an Environmental Assessment (EA) on the mining plan; racing community provides extensive comments on the plan including the fact that under preservation law, the BSF Historic Registry listing triggered obligations by the BLM to consult the State Historic Preservation Officer (SHPO), provide an opportunity for the Advisory Council on Historic Preservation to comment, and provide the racing community with “interested party” status 


BLM approves mining plan and final EA contingent on Intrepid continuing the salt laydown project and returning an amount of salt in brine form equal to the amount of salt they remove from the BSF; the BLM explains that it has not informed the SHPO of degradation at the BSF “because it has never been determined that the conditions of the BSF are attributed to the mining operations, the BLM did not believe it needed to inform the SHPO of anything”; strangely, the BLM also opined in the final EA that “removing mineral from the shallow brine aquifer north of I-80 may be causing the salt layer to thin and retract.  Intrepid’s voluntary continuation of the salt laydown project may not be sufficient to prevent diminishment of the Bonneville Salt Flats (BSF) from drawing off the brine from adjacent areas.  Such diminishment would degrade the unique geology and historical relevance of the site and would disrupt the recreational opportunities that have been part of the BSF for over 80 years.”

BLM denies Save the Salt’s request for “interested party” status and encourages “the Coalition to seek salt laydown results directly from the [mining] Company.”


Public Land Order 6941 extended and set to expire on August 5, 2032


Racers continue to see degradation at the salt flats and worsening conditions on and around the race courses; the racing community, acting through their nonprofit “Save the Salt,” request BLM allow a dry salt laydown test to determine whether dry salt laydown is viable; numerous exchanges between Save the Salt representatives and the BLM take place in which BLM requests further details


After months of exchanges, BLM indicates that the test may interfere with their own ongoing studies and requests Save the Salt prepare an abbreviated EA

Save the Salt works with Bingham Engineering to help prepare the abbreviated EA; based on the engineering report, Save the Salt determines it will not be able to afford the EA process and dry salt laydown plan.


An estimated 2,000 tons of salt were successfully deposited on the mud surface at the end of the access road to the BSF racing area; the surface had originally been covered by salt but has been reduced to mud due to continued salt loss over the years.


Save the Salt internally develops alternatives for improving the conditions at the Bonneville Salt Flats, but is reticent about submitting ideas to the BLM based on previous difficulties in getting the agency to engage on the issue

Save the Salt reaches out to members of Congress in effort to keep BLM engaged on the issue and hopefully direct the agency to undertake additional mitigation efforts