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plants located at points where deposits of limestone upon which they may 

 operate exist would at once solve the difficulty of high quarry prices and 

 high freight rates, but it is a fact that such plants cannot operate as 

 efficiently as the large well-equipped permanently located commercial ship- 

 ping plants. The tonnage life per dollar of investment in other words, 

 the depreciation factor per ton, and the tonnage output per hour relative 

 to investment, the power factor and the labor factor, all are expensively 

 inefficient when compared with the well organized and equipped large and 

 permanent shipping plant. The portable plant is a "Rear Trench" and is 

 indicated as a choice if and only to the extent that the available supply 

 from commercial sources involves exorbitant quarry prices, extra long and 

 expensive freight shipments or excessively long wagon hauls from the 

 nearest local railroad station at which the cars are unloaded. Perhaps 

 the most potent and determining of these considerations is the latter. 

 We have some communities which are ten to fifteen miles, or even farther, 

 from the railroad station, and fortunately in the case of some of these 

 communities, they have local and easily available deposits of limestone 

 of a satisfactory quality. A portable plant for these communities is the 

 only salvation, but the probability is that the pulverized stone turned out 

 by the portable plant in these cases will cost more at the plant than the 

 f. o. b. delivery station price, throughout the state as a whole, of stone 

 from commercial sources. 



. This department has examined, studied and advised on the possibility 

 of establishing portable plants at 181 sites in 35 counties, and we found 

 a large majority of these places were located so close to a railroad station 

 that an enterprise of this kind would not have succeeded because of its 

 inability to compete with a shipped-in supply. I am touching upon only 

 a few of the outstanding considerations in connection with such problems. 

 The questions of the quality of the stone, of its quarryability, of its acces- 

 sibility to the highway, of its availability by purchase or royalty arrange- 

 ment, of the ability to satisfactorily manage and man the work with local 

 talent and keep the outfit reasonably and efficiently busy, are all very 

 vital factors. 



We have in Illinois more commercial quarries and shipping plants 

 than perhaps the average layman realizes. Some of these represent very 

 large investments and output ability. In general, we may say that there 

 are two main producing districts. First, the northeastern or general Chi- 

 cago district producers, which are operating in the extensive dolometic 

 limestone known as the Niagara deposit. Some of the points in this dist- 

 rict at which plants are located are Kankakee, Thornton, Gary, McCook, 

 Elmhurst and Joliet. The second largest group is that of the East St. Louis 

 district. This stone differs from that of the Chicago district in that it is, 

 as a rule, more crystaline, higher in calcium and lower in magnesium. 

 In saying this, I do not wish to be misunderstood as attempting in this con- 

 nection to place either of these stones above the other in its value for 

 soil treatment purposes. Both are good and are needed. There are other 

 individual locations. Without mentioning all, I will mention as more or 

 less prominent the state plant in connection with the penitentiary at Ches- 

 ter, and the commercial plants located at Whitehill in the extreme southern 

 part of the state and at Alton, Marblehead and Gladstone all along the 

 western side of the state, and at Rockford on the north edge. Also, we 

 have just over the line in other states and supplying Illinois with more 

 or less tonnage, plants located at Buffalo, Linwood and Bettendorf, Iowa, 

 and Mitchell and Greencastle, Indiana. 



FOBMS OF LIMESTONE. 



The forms in which raw limestone is produced for direct application 

 to the soil may be divided into three main classes. First, by-product 

 screenings. Second, directly pulverized material. Third, ground stone. 

 Ground stone is not a real factor in Illinois. It is stone that has been 



