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By R. R. Sayers

VENTILATION may be defined as the process by which vitiated air of an inclosed or partly inclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level PER CENT. Oxygen 20.94 Nitrogen 78.09 Carbon dioxide 0.03 Argon 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxid, ammonia, ozone traces CARBON DIOXIDE LIMIT For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent. carbon dioxide.

Jan 7, 1926

By J. M. Armstrong

Jan 1, 1934

By M. L. Jeremic

Mining practice and underground studies show that, besides mining stresses, lateral tectonic stress also influences roadway stability. Roadways perpendicular to the direction of major lateral stress experience the majority of roof falls, accelerated floor heave, and extrusion of coal ribs into openings. They have the most severe deformations and their maintenance is difficult. Roadways parallel to the major lateral stress exhibit roof sagging and bed separation, moderate though sometimes uneven floor heave, and slabbing of coal ribs into openings. Roadways oblique to lateral stress have, to a certain degree, self-supporting roofs, uniform floor heave, and limited sloughing of coal ribs into openings. The optimal orientation of roadways is, therefore, oblique to the lateral stress direction with fewer crosscuts between them.

Jan 1, 1982

By J. D. Miller, M. B. Mooiman

It has been discovered that gold can be extracted from alkaline cyanide solution with primary, secondary, and tertiary amines by adding certain Lewis base modifiers, such as organic phosphorus oxides. Under these circumstances, gold can be extracted at about pH 10, commensurate with the pH of cyanide leach liquors. The selectivity of the amines and amine/modifier combinations for Au(CN)[2] over other metal-cyanide complexes is discussed. Potential applications for the solvent extraction of gold from cyanide solutions are also discussed.

Jan 1, 1985

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Jan 1, 1942

By D. C. Shelton

Eq. 4 and 5 on page 5 of the March 1965 issue of Transactions, and Eq. 12 on page 8 of the same issue should read respectively:

Jan 1, 1965

By G. F. Comstock

H. M. BOYLSTON, Cambridge, Mass.-It might be asked, since this test is so simple, why it was not discovered before. It seems to me the explanation is that when we have used the sodium picrate solution, it has .generally been on a very, high-carbon or hypereutectoid steel; to detect . the presence of free cementite, and when we have looked for sulphides, it

Jan 4, 1917

Page Foreword—H. Foster Bain........................ 9 Letter of Transmittal—F. Julius Fohs...................11

Jan 1, 1927

By AIME

Compiled by Mary Ann Gross, Department of Energy. Bruceton. PA. Supplemental data from Coal Age indicated by (*). Reprinted by permission from CoalAge magazine.

Jan 1, 1981

By A. Whillier

Methods are given for estimating heat flows into mining excavations of various types, with an example to illustrate how the refrigeration requirements are then determined after allowing for the cooling effects of the ventilation air.

Jan 1, 1981

AARONS, J. BOYD, Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th Reserve Engineers. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy Supt. (Captain), New York State Troopers; Captain, 22d Regiment, N. Y. N. G. BARLING, H. B., 1st Lieutenant, Engineer Officers' Reserve Corps. BIGELOW, BRAXTON. BLOOMFIELD, E. C., Lieutenant. BORROW, F. K. BROOKS, ALFRED H., Captain, Engineer Officers' Reserve Corps. BROWNE, DE Courser, 1st Lieutenant, Ordnance Dept., Fortress Monroe, Va.

Jan 8, 1917

By L. O. Howard

THE CHAIRMAN (WALTER DOUGLAS, New York, N. Y.).--I presume, gentlemen, that Mr. Howard's experience with the Great Falls basic-lined converter has been as regards the tonnage produced from a single lining, perhaps, a world's record. About 6 months ago Mr. Howard shut down and tore out what was left of the first basic-lining which was installed at the Old Dominion, the lining having produced something over 70,000,000 lb. of copper. This was due probably not only to the very excellent grade of the matte which was produced by the smelter there,

Jan 12, 1916

AARONS, J. BOYD, Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th -Reserve Engineers. BAINS, THOMAS M., Major, Engineer Officers' Reserve Corps. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy Supt. (Captain), New York State Troopers; Captain, 22d Regiment, N. Y. N. G. BARLING, H. B., Ist Lieutenant', Engineer Officers' Reserve Corps. BIGELOW, BRAXTON. BLOOMFIELD, E. C., Lieutenant. , BORROW, F. K. BROCK, R. W., Major, 19th Reserve Battalion of Canadians. BROOKS, ALFRED H., Captain, Engineer Officers' Reserve Corps. BROWNE, DE COURCY, 1st Lieutenant, Ordnance Dept., Fortress Monroe, Va.

Jan 9, 1917