MABViNE.] GEOLOGY ROCES EAST OF FEONT EANGE LIGNITIC. 119 



is no doubt but that the lignites of Colorado could be employed in any 

 process embodying this principle. The " plant," however, is expensive, 

 and has so far only been economically used, so far as I know, in large 

 iron operations, the ore necessary for which is still wanting in the far 

 West. The principle of producing and using the gases from these coals, 

 however, could still be applied when such high temperatures as require 

 the use of the " regenerators " are not desired. 



A successful type of a pulverized fuel process is that of Messrs. 

 Whepey & Storer. In strong contrast with the expensive plant of the 

 Siemen's process, the essential piece of apparatus here is a machine dif- 

 fering but little from a fan-blower. The coal, first screened to the size of 

 coarse gravel, is automatically fed into a cylinder varying from 12 to 30 

 inches in diameter, in which a paddle-wheel revolves at the rate of from 

 1,500 to 3,000 times per minute. Caught in the rapid revolutions of 

 this paddle — the particles abrading one another in the swift air-cur- 

 rents — the coal is rapidly pulverized to the finest dust, and, with the 

 accompanying air, is forced in a constant stream through a short pipe a 

 few inches in diameter into the previously slightly heated fire-place 

 beneath the boiler, or into the combustion-chamber of the furnace, as 

 is the air from an ordinary fan-blower, every minute particle of coal 

 floated upon and surrounded by the very air which is to burn it, while 

 the supply of either coal-dust or air can be instantly regulated and 

 varied in amount until so proportioned to one another as to produce the 

 most perfect combustion. Indeed, the conditions for combustion here 

 seem almost perfect, so that, notwithstanding the apparent inadequacy 

 of the means employed, the highest metallurgical heats may be obtained 

 and used on a large scale. It is easily applicable to common boilers, or 

 most heating appliances, and generally requires but slight change in 

 the original apparatus. 



Aside from the portability and ease of api^lication of the apparatus, 

 important considerations in the West,) the process appears to be so 

 )articularly adapted to these friable coals, especially in view of the 

 (ifficulties surrounding their application in other ways, that it seems as 

 lit were in this direction that the hgnitic coals of the West could be 

 bst rescued from the metallurgical difficulties which now surround 

 tlem. It is certainly a process which is aided by that very character 

 olthese coals which renders them unfit for use by the usual methods.* 



DISTRIBUTION AND DEVELOPjMENTS OF THE LIGNITIC COAL. 



'>n the accompanying map (figure 4) will be found indicated nearly 

 allthe points at which openings have been made on coal deposits within 

 mjdistrict, the positions of which with respect to the sections, with but 

 few exceptions, have been very kindly furnished me by Mr. E. L. Berth- 

 ouc of Golden City. These openings are indicated by prominent black 

 squres, the names of the mines, or their owners, being in most cases 

 attched to them ; while the outcrop of the coal horizon, as inferred 

 • froi these openings, is given in the strong black line to better empha- 

 size.ts position. 



Oer most of this region this outcrop is hidden from view by the 

 supcincumbent horizontal terrace-beds or detrital material. Along the 

 wesirn edge of the maps are the abrupt ends of the massive mountain- 



* Fr a clear and simple statement of the chemical principles which underlie the com- 

 bnatii of fuel, and of the practical considerations affecting the carrying out of these 

 princiles, and realizing the full value of the fuel, the reader is referred to James Mac- 

 I'arlai's Coal Regions of America, New York, D. Appleton & Co., 1873, pp. C2G-C38. 



