MINING. 123 
The grade stick can be so adjusted that the same muscular 
strength will be rexuired to push the full car down, as to 
push the empty car up, the only trouble being to put the 
grade stick on the track when laying it, and support or 
lower the ties until the bubble sets right. On the diagram 
the distances between the hoisting slopes are spaced in 
pannels of 900 feet, but that distance can be lengthened or 
shortened to suit the locality and the seam. The method 
of working “medium dip” seams, has less amount of narrow 
work to a given acreage of coal than any other method yet 
made known, excepting the “long wall” method, and before 
we can adopt the latter, we must reduce the size of our 
cars, and train and discipline our miners to work under a 
“sagging” roof, and if the “long wall” is the “withdrawing” 
kind, we must lay tracks along the “face or breast.” The 
hoisting power at the top of each hoisting slope, can be 
either steam or electric motor connected with a central 
dynamo. If steam is used, the water would probably have 
to be piped from the drainage slope. 
The long underground haulage is one of the chief draw- 
backs to our “medium dip” seam mining; in some districts 
the usual way to curtail that expense is to establish the un- 
derground wire rope haulage system. In the “combination 
method” the car bodies are strongly made wooden boxes 
of rectangular shape, of one ton capacity. These are de- 
tachable from the trams or trucks. In the rooms, the trams 
consist ofa flat platform resting on the trucks, and of a size 
sufficient to hold a single car body. In the hoisting slope, 
the “hoisting” or “slope” tram consists of a long iron 
frame work on truzks, on which are constructed four steps 
or scaffolds, so arranged with reference to the slope of the 
track, as to have the floors of these platforms level at the 
steepest part of the slope. On each of these platforms 
is placed one of the detachable car bodies above referred to. 
The Diagram following p. 124 shows the construction of the 
“slope tram” with a car body resting on each of the four 
platforms, with ground plan of slupe and room roads; also 
longitudinal cross sections of slope, showing hoisting tram. 
The miner takes the empty mine car body from the “slope 
tram” and replaces it with a loaded or full one, signals to 
