http://pec.lib.wvu.edu/record/P194751944Control of silicosis hazard by substitution of quartz-free or low-quartz material for sand under mine locomotives.<p> Serial issue. Issued as: United States. Bureau of Mines. <em>Information circular</em>, 7297 (1944:Oct.).</p>Schrenk, H. H. (Helmuth Herman), 1902-Brown, Carlton E.Silicosis.Coal miners--Diseases.Lungs--Dust diseases.Dust control.14256