00754cam a22002171 4500 gs 27000056 DLC 20260227111331.0 920604s1926 enkaf f000 0 eng c gs 27000056 (OCoLC)25937148 Library, U.S. Geological Survey CSt DLC TN295 .G65 no. 23 Hay, Peter Stewart, 1884- A method of trapping the dust produced by pneumatic rock drills, by P.S. Hay. With a preface, by Professor J.S. Haldane ... London, H.M. Stationery Off., 1926. 18 p. 2 fold. pl., diagrs. 25 cm. [Gt. Brit.] Safety in Mines Research Board. Paper no. 23 Mine safety. Rock-drills. 26539 26539