122 GEOLOGICAL SURVEY OF ALABAMA. 
mining districts, is, in my judgment, superior to any other 
method for seams having a dip of from 10 to 25 degrees 
from the horizontal: it is the best suited to our seams, our 
mine cars, to our miners, and to our “pillar and room” 
habits of working; and, as it is a combination of methods 
partly used in one, and partly in other districts, we shall 
designate it as the ‘“ Combination method.” 
In this method, the system of conducting the underground 
workings is, to have but one single track slope driven in the 
direction of the dip. This we will name the drainage 
slope; the pumps being in a narrow air-way at one side of 
it. By this slope all the coal withiu its jurisdiction or 
tervitory will be drained, and it will also be the medium 
through which the coal and slate of the adjoining gangway 
end hoisting slope must be brought to the surface. All 
work in this system will be driven either horizontally or 
directly up the rise of the coal, (excepting the draining 
slope.) 
The diagram opposite gives an outline of this system of 
working. 
A pump and air-way is driven up at one side of the 
drainage slope, and hoisting slopes are driven up atsuitable 
distances on each side of the drainage slope. In order to 
avoid the expense connected with long underground haulage, 
the rooms are all driven horizontally or nearly so, the grade 
of the room tracks must be laid to the proper inclination, 
by means of a tapering grade stick, with glass level im- 
bedded in plaster of Paris, and adjusted to a three-eights 
grade (or 3-8ths of an inch to the hundred inches), or to 
such grade as the size and style of wheel used in mine cars 
may require. 
The drainage slope will require coal pillars large enough 
for its permauent security. With this method a room can 
be advanced 150 yards with no more outlay of strength and 
muscle to deliver the coal a.d secure an empty car, than 
will be required to advance a room 150 feet diagonally up 
our “medium dip” seams, or in other words the miner can 
push his full car out, and return with the empty 150 yards, 
at less cost and exertion, than would be expended in the 
same work through 150 feet in the diagonally driven room 
up the pitch of our medium dip seams. 
