Geochemical and Physical Characteristics of Iraqi Dust and Soil Samples

Affiliation(s)PI/CoPIFunded by
DEES

McDonald, Eric
Caldwell, Todd

U.S. Army Yuma Proving Ground, Natural Environments Test Office

Collaborators:

  • Dr. Russell Harmon - Environmental Services Division Army Research Office
  • Mr. Graham Stullenbarger - U.S. Army Yuma Proving Ground-Natural Environments Test Office
  • Mr. Larry Havrilo - U.S. Army Yuma Proving Ground-Natural Environments Test Office
  • Mr. Dave Pond - U.S. Army Yuma Proving Ground-Yuma Test Center
  • Mr. Byron R. Cooper - U.S. Army Yuma Proving Ground-Yuma Test Center
  • Lt. Col. Dan Gilewatch, PhD - United States Military Academy-West Point
  • Col. Chris King, PhD - United States Military Academy-West Point
  • Dr. Lillian Wakely - Engineer Research and Development Center Geotechnical and Structures Laboratory
  • Ms. Julie Kelly - Engineer Research and Development Center Geotechnical and Structures Laboratory

Keywords: dust, weapon lubricant, Middle East, soil mechanics, YPG

Project Description

For the U.S. Army to operate successfully on a global scale, current and future troops as well as their equipment must be capable of accomplishing any mission in all possible environments: cold or hot, wet or dry, and every possible combination of terrain. This requirement challenges the Army's equipment, people, and training programs. To prepare for a full spectrum of operations, the Army develops and tests its equipment under extreme environmental conditions to ensure that America's soldiers have the best that science and technology can provide. Further, units conduct training in a realistic manner and in environments that simulate various natural settings. Finally, the Army must collect and analyze environmental data necessary to successfully plan for contingencies worldwide.

A very  fine  layer of dust accumulated on the mechanism of an M16. This has led  to  incidents of weapons jamming during operations in Gulf States  (Photo  courtesy of Julie Kelley, ERDC).
Click to enlarge image

A particular and critical issue has evolved from U.S. combat experience in Iraq. Troops have reported that their individual combat weapons (M4 and M16 rifles) were jamming and failing to fire dependably. No specific causes were identified, but anecdotal information suggested that the problem was related to high levels of dust in the area combined with the properties of standard Army cleaner, lubricant, and preservative (CLP). Some troops had acquired commercially available gun lubricants that were reported to work better. An Army study (King et al., 2004) identified that dusts present in the world's deserts vary greatly in physical and chemical properties, variables that have significant implications for military operations. This recent experience and knowledge has reinforced the importance of understanding the impacts of desert environments on military operations, especially in critical areas such as proper functioning of weapons.

(Image, above right: A very fine layer of dust accumulated on the mechanism of an M16. This has led to incidents of weapons jamming during operations in Gulf States (Photo courtesy of Julie Kelley, ERDC).

 

Recognizing that weapons jamming could be related to physical and chemical properties of dust, the Desert Research Institute (DRI) was commissioned by the Army to undertake an analysis of a limited number of Iraqi dust samples collected during the period 27 March - 8 April 2004 by an onsite geologist of the U.S. Army Corps of Engineers. The purpose of this study is to describe the physical and chemical properties of sampled Iraqi dust, to analyze how this dust reacts with gun lubricants used in Iraq, and to develop recommendations for additional testing that would contribute to solving the gun-jamming problem for U.S. soldiers. This first-phase study is intended to provide a scientific basis for addressing dust-related aspects of the problem, not to provide a final solution.

(Image, below right: Dust analyzed was collected by USACE Geologist Julie Kelley during operation in Iraq from tactical vehicles including Humvee floorboards. Both dust and sediment samples were found to be higher flocculant in weapon lubricants)

 

Dust  analyzed was collected by USACE Geologist Julie Kelley during operation  in Iraq from tactical vehicles including Humvee floorboards. Both dust  and sediment samples were found to be higher flocculant in weapon  lubricants.
Click to enlarge image

Fifteen Iraqi dust samples were collected in total. Of these, nine were bulk surface soils collected at a variety of locations and were intended to capture some of the variability in dust sources based on the geology and geomorphology of the region. To evaluate potential differences between parent soils and resultant dust, six additional samples were taken inside tactical vehicles where weapons were stored or transported. All samples were analyzed to determine particle size, chemical composition, and reactivity of soil or dust components. Eight of the samples were tested to determine reactivity with three types of gun lubricants, including government stock CLP and two commercial products that troops found to work better than standard CLP. Analytical results describing physical and chemical properties of the Iraqi dust samples provide scientific guidance for the next steps in solving dust-related problems. The most critical findings from this study are:

  • Soils and dust collected from areas of military activity in Iraq differ significantly from the material used in chamber-testing procedures for weapons and are unlike natural geologic materials to which weapons are exposed during most training environments in the U.S.
  • The concentration of reactive chemicals, primarily salts and carbonates, is high in all Iraqi dust and soil samples and extremely high in many. Several of these reactive chemical components have the potential to corrode metal parts.
  • The average particle size of dust encountered in military operations in arid regions is much smaller than laboratory-generated quartz surrogate dust used in sand-and-dust chamber testing of weapons. Army experience has clearly shown that natural dusts have a significant impact on weapons operation and other mechanical equipment.
  • Laboratory testing has shown that three gun lubricants react with Iraqi dust, forming aggregates that increase the average size of particles in the sample. The extent of the reaction varies among dust samples with different chemical compositions and grain sizes. In general, dusts higher in salts and carbonates, and with smaller particles, are most reactive when mixed with the lubricants.>
  • The average particle size of dust taken from vehicles in Iraq was significantly smaller than the particle size of bulk soil samples. Further, the samples from vehicles had a higher concentration of reactive carbonates and sulfates. This reinforces that current chamber test methodology misrepresents real-world conditions.

Identifying the complete cause of gun-jamming problems experienced in Iraq must include testing with actual dust, or the equivalent, from the areas where the problems occurred. Differences in bulk soil samples compared with dust found in military vehicles operating in Iraq verify that operational considerations must be included in designing tests to evaluate and resolve this issue. Moving vehicles, and the weapons carried therein, act as natural dust traps for the smallest, and most potentially reactive, dust particles.

Given the importance of Iraqi dust in its potential to impact military equipment and operations, desert environmental parameters are critical to design tests that reflect real-world conditions-especially conditions most likely to compromise use of critical equipment in harsh desert environments. Previous work by King et al. (1999, 2004) demonstrated that each type of equipment test has a unique set of environmental conditions that are critical to the success of that test. Further analyses of the chemical properties of Iraqi dust are recommended to evaluate potential for corrosion and related impacts to military equipment.

This study quantified physical and chemical characteristics of dust derived from soils sampled in Iraq. This dust was found to be highly variable based on its origin and significantly different from the quartz materials used for standard chamber dust tests of military equipment. Further, the high concentrations of reactive chemicals and high volumes of fine clay materials were observed to react with chemicals found in gun lubricants.

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