528 GEOLOGY OF NORTHWESTERN TEXAS. 



eight to thirty inches, and is very uniform in thickness throughout the entire 

 property. This seam of coal has a thin parting of slate in the centre of 

 about one-fourth of an inch. 



The method of working the mine is what is known as the " long- wall ad- 

 vancing " system. By this system all the coal is taken out in a circle around 

 the shaft, after having left one hundred feet square of solid coal around the 

 shaft on which the hoisting machinery is placed, and through which also the 

 main entries are driven after all the coal is taken out, and "gob," the dirt 

 taken out from under the coal, is put back in the vacancy left by taking out 

 the coal, and the roof is allowed to settle down all around. To prevent the 

 roof from settling down against the face of the coal, it is supported by tem- 

 porary props, which are afterwards taken out or left, as may be conveni- 

 ent. Plate No. IX will give an idea of the workings of the long-wall system. 

 This plate shows the one hundred feet of solid coal left around the main 

 shaft, with the main entrances running in four directions, with the broken- 

 down walls behind the miners; the open space between the "gob" and work- 

 ing face of the coal. Plate No. X shows a vertical section of the same. 



The props used in this mine are made of wood, and are about thirty inches 

 long. On the top of the props is placed a cap a foot wide and eighteen inches 

 long, to prevent the props from sinking too rapidly into the descending roof. 

 The timber for these props and caps is gotten from the timber in the immedi- 

 ate vicinity of the mine. 



There are three openings on the property, known as shafts No. 1, No. 2, 

 and No. 3. No. 1 was the first one put down, and is fifty feet deep, and is the 

 farthest one to the east. No. 2 is thirty-nine hundred and sixty feet north 

 41° west from No. 1, and No. 3 is forty- two hundred and thirty-nine feet 

 southwest from No. 2. Plate No. XI shows tbe various places mentioned. 



The coal is brought to the bottom of the shaft from the face of the coal in 

 mine cars drawn by mules. The mules are fed and watered and stabled in 

 the mine. The coal is hoisted out of the mine in cars and dumped directly 

 into the railroad cars for transportation, passing over a screen at the tipple. 

 Men are placed on each car as it is loaded to throw out any slate or other 

 matter not desired that may have been negligently left mixed with the coal 

 by the miner, and in this way the grade of coal put on the market is kept 

 comparatively clean. No attempt has been made to utilize the waste from 

 the mine, except an occasional sale of a single carload to be used by some sta- 

 tionary engine. 



The average output of this mine is about seven hundred tons per day. The 

 entire output is taken by the Texas and Pacific Railway Company and used 

 on the western division of their road. The reports of its use by the locomo- 

 tives shows it to be satisfactory. 



