SEVENTH ANNUAL MEETING 27 



The statistical work of the U. S. Geological Survey is car- 

 ried on under the direction of twenty or more geologists who 

 have become expert in regard to special mineral industries. 

 Over 62,000 operators report annually the details of their pro- 

 duction, but this report is supplemented by personal visits of 

 experts to significant operations in all mineral lines. 



Specialization in study of water resources is now common 

 throughout the country. The U. S. Geological Survey main- 

 tains twelve district offices in the country and records the 

 stream measurements from over 1100 stations. It also has 

 experts in underground-water studies. A series of reports 

 on this subject for the entire coastal-plain region of the At- 

 lantic and Gulf states has been completed. 



Among the subjects covered by the state surveys from year 

 to year may be mentioned those of the 1913 program, as 

 typical. Reports were issued by various states on : Building 

 stone, cement materials, agricultural limestone and marl ; stone 

 and gravel for highways, concrete and ballast ; clay, shale and 

 fire-clay ; asbestos, soapstone, feldspar ; salt, gypsum, glass- 

 sand, lithia, rock-phosphate; coal, lignite, peat, petroleum, 

 gas; precious metals, iron, lead, zinc, copper; underground 

 and surface waters. 



TECHNOLOGIC STUDIES 



Finally a view of investigations of the mineral industries 

 would be incomplete without consideration of technologic 

 studies. These are doubtless in progress in innumerable lines 

 by chemists, metallurgists, and engineers employed by corpor- 

 ations and other interests, and the resulting increased effi- 

 ciency in recovery and utilization of mineral products, and in 

 safety of employes is truly remarkable. Among the lines of 

 public investigation and experiment by the U. S. Bureau of 

 Mines, by various mining schools, and by the state surveys 

 should be mentioned the following: 



Increased safety and efficiency in mine timbering, ventila- 

 tion, hoisting, and in use of explosives and electricity ; elimin- 

 ation of explosions due to gas and to coal dust ; perfection of 

 processes for by-product coking, briquetting, and for gas- 

 producer operation ; recovery of low-grade ores and of col- 

 loidal slimes, and other milling wastes; smelting of refractory 

 ores and recovery of waste gases ; practical tests of clay ma- 

 terials for extended uses ; checking wastes of natural gas and 

 extending the life of oil fields by preventing refrigeration and 

 precipitation in the sands, and by controlling movements of 

 water in the sands. 



