This is an archived article that was published on sltrib.com in 2015, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

Sadly, 2015 Speed Week and World of Speed events were cancelled by the racing community due to undesirable surface conditions (partially dissolved surface salt-crust layer or stratum) that prevented establishment of a race course having sufficient length required for record setting.

Some members of the public believe that this year's poor racing surface is proof of purported Bonneville Salt Flats deterioration and that it is solely due to brine extraction by a potash mining company. They also believe that U.S. Bureau of Land Management has not been sufficiently rigorous in its protection of the salt flats. Disputing facts follow.

All potash production from the salt flats prior to 1963 was from private land south of Interstate 80, which was patented between 1917 and 1927 under the 1872 mining law. Potash production north of I-80 from collection ditches on the eastern margin of the flats, is from a federal lease issued by BLM in 1963; production is a small percentage of total annual production. This lease was issued prior to the 1969 National Environmental Policy Act with its requirements to consider impacts to the environment. The federal lease is a valid existing right subject to specific conditions set forth in the lease.

It is indisputable that surface salt-crust stratum conditions are changed this year from previous drought-influenced years. May 2015 was wettest on record during the 1997 - 2015 period (Western Regional Climate Center, http://www.wrcc.dri.edu/). Although surface salt-crust stratum has changed this year, overall mass and volume of the salt flats remains relatively unchanged. This is based on BLM salt crust thickness studies conducted in 1988, 2003, and field-checked in 2015.

The 2003 study concluded that there was virtually no change in salt crust mass and volume during the 15-year period between 1988 and 2003 when the same measurement method was used. Since there was no change in volume, purported annual depletion rate of 1.1 percent generated from the 1988 study was shown to be invalid. Consequently, perception that Bonneville Salt Flats is disappearing at this erroneous depletion rate is unsupportable based on thickness data and volume calculations from the 2003 study.

Responding to the racing community's concerns, BLM and University of Utah geologists examined salt-crust exposures at mile posts 3 and 5 of Speed Week's 2015 proposed race course. During the July 15 examination, they observed that surface salt-crust stratum had thinned, become soft and slushy in some areas, and like scattered popcorn in others, exposing underlying thin gypsum stratum. However, when BLM augered bore holes adjacent to each mile post, they measured an additional 2 to 3 feet of salt thickness present beneath the thin, 0.5 to 1-inch thick gypsum stratum. These thicknesses are consistent with total salt-crust thicknesses measured from nearest bore holes drilled during BLM's 2003 salt-crust thickness study.

BLM engaged in a cooperative agreement with two potash mining companies (Intrepid Potash Wendover, LLC and predecessor, Reilly Industries, Inc.) to conduct an experimental Salt Laydown Project to replenish salt to Bonneville Salt Flats. Between 1997 and 2012, an estimated 9.8 million tons of sodium-chloride salt were transferred from company private land to the salt flats north of I-80. Since 2012, another 1.5 million tons have been added for a total of 11.3 million tons to date.

BLM's monitoring and data collection from the Laydown experiment and the subsequent 2003 salt-crust thickness study produced three peer-reviewed published papers, which assessed the Salt Laydown Project's efficacy (see "Salt Flats Research," http://www.blm.gov/ut/st/en/fo/salt_lake/recreation/bonneville_salt_flats.html).

Based on these published papers and review of Intrepid's 2006 mining and reclamation plan, BLM mandated that Intrepid continue the Salt Laydown Project for life of lease. Intrepid is also required to quantify and report salt tonnage being withdrawn from federal-lease collection ditches. Furthermore, tonnage extracted from federal-lease collection ditches north of I-80 may not exceed tonnage being replaced through the Salt Laydown Project, and Intrepid must perform a salt-crust thickness study similar to BLM's 2003 study by 2018.

Intrepid recently contracted with Brenda Bowen, Associate Professor, Geology & Geophysics, University of Utah, to conduct the 2018 salt-crust thickness study. BLM will use results of the 2018 study to determine if additional mitigating measures will be necessary in management and protection of Bonneville Salt Flats.

William White is a registered professional geologist (Idaho & Utah), and was BLM's physical scientist responsible for monitoring and assessing progress of the Salt Laydown Project from 1997 through 2007.