[4] The drum of the mill has a single shelf plate that scoops test samples and steel balls from the bottom, lifts them up and then drops them, creating a crushing impact.
[6] Crushed sample is then separated from fine dust on a sieve, washed, dried and weighed.
[8] In the 1930s, national studies demonstrated the Deval test did not correlate with the service record of sampled rock altogether, while an LA loss rating of less than 40% was a reliable indicator of quality.
[9] The federal standard for LA abrasion testing was formally adopted by the ASTM in 1937.
[10] Decades later, field studies found that the LA test results do not always correlate with reality, thus engineers outside of the United States developed different national standards like the French wet micro-Deval procedure or the British Standard 812.