COAL DEVELOPMENT. 49 
about thirty other small mines and prospects of any consequence 
within the area here reported; these are listed and their locations 
are shown on the map, Plate I. 
The coal is opened at or near the outcrop and generally is worked 
by the room and pillar system. Where the dip is appreciable entries 
are run with the strike and the rooms are opened principally up the 
rise. The long-wall system is used at only one mine, the Riverside. 
Botli roof and floor are generally a firm sandy shale. The workings 
usually are dry and little trouble is caused by water, but in a few 
instances, as at the Cameo mine, water level has been reached. Some 
of the workings are extremely dry and dusty and care must be taken 
to avoid explosion. Natural ventilation is chiefly depended on, 
though furnaces are used to some extent. Machines have not been 
introduced and in general the methods of mining are simple. The 
following brief descriptions will serve to indicate the present, stage of 
development: 
The Book Cliff mine, operated by the Book Cliff Coal Company, is 
situated in a small ravine in the Little Book Cliffs, about 12 miles 
north of Grand Junction. The mine is connected with the Denver 
and Rio Grande Railroad by a narrow-gage road, and the camp con- 
sists of a number of frame houses, a company store, workshop, etc. 
(See PL X.) Good water is supplied in moderate quantity from a 
near-by spring, which was an important factor in determining thp 
location of the mine. 
Considerable prospecting has been done in this vicinity. The lower 
bed was formerly worked; it has the advantage over the upper bed of 
being slightly better in quality and of outcropping about 190 feet 
lower down the cliffs. The old mine a is situated in the ravine next 
south of the one in which the present workings are located, and was 
approached by a steeply inclined tramway. The coal was reached 
by a tunnel cut through the underlying sandstone. Development 
proved, however, that the lower coal bed in this vicinity varies greatly 
in thickness, ranging from a few inches to about 4 feet, and after a few 
years work on the lower bed was abandoned. A considerable quan- 
tity of coal was mined, however, the largest production of any one 
year being reported as 18,000 tons. 
In the present mine, which was opened in 1903, the upper coal is 
worked. It is reached through a tunnel, the mouth of which is sit- 
uated near the lower coal outcrop, about a quarter of a mile north- 
east of the terminus of the branch railroad and some 200 feet above 
it. The tunnel extends northeastward through a heavy bed of sand- 
stone a distance of 750 feet, where the upper coal is encountered. 
From the end of the tunnel entries extend northwest and southeast 
a Lakes, Arthur, The Book Cliff coal mines. Mines and Minerals, vol. 24, L904, p. 280. 
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