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RIO GKRANDE COAL FIELDS OF TEXAS.
[BULL. 164.
Penrose says: x " The San Tomas coal is so vastly superior to any of
the east Texas lignites that it can not fairly be classed with them."
He gives the following analyses of the east Texas lignites and of the
Laredo and Eagle Pass coals. They are presented here for purposes of comparison.
Analyses of Texas lignite's.
Analyses of Laredo and Eagle Pass coals.
Conclusions Regarding the Rio Grande Eocene Coals.
These coal (or more properly lignite) fields are simply the westward continuation of the great lignitif erous Eocene belt of eastern Texas and the Gulf States as far east as Alabama. The coal beds of the Rio Grande region range in position from Midwayan to Chickasawan. The beds on the Neuces, in northern Zavalla County, are Midwayan, while those around Carrizo Springs and Santo Tomas are Chickasawan.
Although the Eocene contains many lignite beds, most of them are not of economic value for various reasons. They, are often thin and impure, and, because of a large content of moisture or because of an unconsolidated mechanical condition, must undergo mechanical treat ment by being pressed into briquettes. These questions are discussed by Dumble in Brown Coal and Lignite. 2
The only place where these Eocene coals are being worked is in the vicinity of Santo Tomas. The coal there is sufficiently hard to need no treatment. In such an investigation as this it is not possible to make
i First Ann. Kept. Geol. Survey of Texas, 1890, p. 97. 2Geol. Survey of Texas, 1892.
Water.
Volatile matter.
Fixed carbon.
Ash.
Sulphur.
Per cent.
Per cent.
Per cent.
Per cent.
Per cent.
Rockdale, Milam County
19.925
52. 425
22. 000
5.650
1.235
Atascosa County
13.285
59.865
18.525
8.325
2. 360
Athens, Henderson County
9.100
42.200
7.375
41.325
0.625
Rusk County
16.825
46. 325
31. 475
5.375
1.090
Calvert bluff, Robertson County
16.475
58.400
18.675
6.450
1.330
Shelby County
18.260
43. 510
29.530
8.700
2.460
Leon County
14.670
37. 320
41.070
6.690
0.250
Rockdale, Milam County
13.800
43.550
36.830
5. 320
1.350
Water.
Volatile matter.
Fixed carbon.
Ash.
Sulphur.
Per cent.
Per cent.
Per cent.
Per cent.
Per cent.
Laredo coal
2.5
51.05
39.1
7. 35
1.5
Eagle Pass coal
3.675
39.42
41.7
15.205
0.81
