SOME PROBLEMS IN CONSERVATION 39 



The natural resources are readily divisible into two distinct 

 classes accordingly as they are not renewable, or are renewable. 

 The first class comprises the mineral products including the min- 

 eral fuels and the metals, which are not renewable and whose ex- 

 haustion is certain to come in time. The best that conservation 

 can hope to accomplish is to defer the date of exhaustion. 



The second class includes the soil and its products, the forests, 

 and the waters. 



The natural resources belonging to the first class are relatively 

 unimportant in Iowa. It is true that a considerable area is under- 

 lain by coal of workable thickness and there are lesser areas of 

 gypsum, iron ore, and lead and zinc. The production of these 

 mineral products is quite insignificant when compared with the 

 products of the soil. While the actual and potential v^lue of the 

 waters, clay, shale, stone, sand and gravel quantitatively are much 

 more important than the mineral products before listed, they too 

 are relatively unimportant in the inventory of natural resources 

 for Iowa and will receive but passing notice in the present paper. 



In dollars and cents coal is the most valuable of the mineral 

 resources now being developed. The state has been notably lax 

 in permitting most wasteful methods in mining, in the prepara- 

 tion, storage and use of coal. In most of the Iowa coal fields, less 

 than seventy per cent of the seam mined is actually hoisted to the 

 surface and scarcely more than two-thirds of this will grade as 

 lump coal. As a rule only one seam is developed in coal basins 

 where two or more workable seams are present, and this without 

 regard to its position to the remaining seams which may be de- 

 stroyed for all time through removing the coal from the single 

 seam: 



The methods now in use are even more wasteful in the han- 

 dling and consumption of coal. The ordinary hot air furnace and 

 steam boiler are very low efficiency mechanisms. Problems 

 worthy of the best efforts of the mining engineer, the gas engin- 

 eer, and the mechanical engineer have to do with fuel conserva- 

 tion. 



Similar problems present themselves when the other mineral 

 resources of the state are considered. Limestone and shale when 

 properly blended and heated to a high temperature and then re- 

 duced to a fine powder become Portland cement. Immense quan- 

 tities of impalpable dust are wasted in the process; in fact worse 

 than wasted, because this dust becomes a nuisance in the vicinity 



