GEOLOGY IN EVERYDAY LIFE — MANSFIELD 259 



Actually, however, these industries are interdependent. Manufactur- 

 ing needs minerals both for its machines and for the power to operate 

 them. The products of mines contribute nearly two-thirds of the 

 revenue freight handled by the railroads and about one-fourth of the 

 ocean-borne traffic. Agriculture requires minerals for fertilizers and 

 farm implements, and minerals serve to link farms and markets. 

 Highways, railroads, trucks, and trains are all of mineral origin. 



To those who actually mine coal, iron ore, and other minerals, the 

 relation of geology to their everyday lives can hardly fail to be evident. 

 The continuity of a vein, the nature of the ground, whether hard or 

 soft, broken or stable, are factors which control the nature and speed 

 of each day's work and the daily risk of personal safety. Similarly, 

 the oil or water driller must keep close watch of the nature and attitude 

 of the rocks through which he is drilling his well. Those who fabricate 

 the product of the mines and wells are further removed from the direct 

 effects of geology, but they are no less dependent on it, because their 

 employment is contingent on the constant supply of a uniform material 

 suitable for the manufacture of their special product. 



Water is as truly mineral as petroleum or other hydrocarbons, and 

 the question of adequate water supply is closely linked with mineral 

 industries. Water is so essential to all phases of human life that no 

 one can escape the consequences of failure, interruption, or contamina- 

 tion of his regular supply. An adequate supply of water is contingent 

 on numerous factors, many of which are geological. 



The economic geologist is employed to aid in the discovery of mineral 

 resources, to work out their relations in the ground, and to obtain 

 quantitative data on which to base estimates of reserves. He must 

 consider grade and accessibility, as these factors ultimately determine 

 whether a given mineral deposit can be exploited at current price 

 ranges. The use of sound geological investigation and advice is essen- 

 tial if waste and suffering are to be avoided by the public when 

 attempts are made to work an unprofitable mining property, to drill 

 for oil in unfavorable places, or to unload questionable mining or 

 drilling enterprises on the market. 



Metals. — The geologist engaged in studying metallic minerals must 

 devote a large share of his time in the field to the available under- 

 ground workings in such mines as are accessible to him, besides 

 acquainting himself with the surface geology of as much of the region 

 as the limits of his time and funds will permit. He thus gains a 

 better three-dimensional picture of the whole geologic set-up than 

 would be possible from a study of surface relations alone. His maps, 

 sections, and laboratory studies serve to control actual mining opera- 

 tions and guide explorations for further supplies of ore. The increas- 

 ing use of geologists on the staffs of mining companies bears witness to 



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