972 ; GEOLOGY OF OHIO. 
soft, plastic clay, but it makes a good and safe floor when properly | 
drained. If water is allowed to stand in entries, the clay soon softens 
and rises. 
While the normal dip of the seam is maintained, there are local 
pitches to the northward that confuse the drainage to some extent. The 
matter of drainage is effected in this mine in an unusual way. Mr. 
John Wallace, the engineer, has invented and patented an automatic 
pump, that for simplicity of plan and efficiency of execution, deserves the 
highest praise. It is in reality a very valuable contribution to mining 
engineering. | | 
_ The coal is brought through the front hills of the Hocking Valley 
which are now mainly exhausted, by a mine locomotive. | 
The mine is worked ona single entry plan, which has thus far 
mainly prevailed in the Hocking Valley. The seam lies so high that 
it is comparatively easy to drive entries through to day and thus a 
natural circulation is secured, which, though inconstant and somewhat 
inadequate, obviates the necessity of a thorough-going artificial system 
of ventilation. The coal is worked altogether on face and ends. Rooms 
are 24 or 25 feet wide, and 75 to 100 yards deep. Ribs between the 
rooms are left but 4 feet wide, and not much effort is made to draw 
them. A little coal is sometimes saved from them, but about 14 per 
cent. of the seam can be counted as sacrificed in this one item. The 
entry pillars are about 30 feet thick. 
The Butler mining machine is in use in this mine, and gives ample 
satisfaction. The Company rents the machines to competent and respon- 
sible miners, who take a contract to deliver the coal. The contracting 
miner pays the company 20 cents per ton for the use of the machine, 
with 70 cents mining rate. He sub-lets the loading and delivery of the 
coal at 17 cents per ton, and employs two day-hands to work with him- 
self at the machine. The machine miners, under these conditions, find 
themselves better paid than they would be by the use of pick and drill. 
The problem of machine mining is considered to be best solved in this 
way under present conditions of the valley. 
The Brooks mine has always been under energetic and efficient 
management as to amount of coal sent out. Its jpresent normal output 
is from 50 to 60 cars per day. It has loaded 93 cars in a single day. 
This record places it well to the front among Ohio mines. 
The composition of the coal of the Brooks mine is given below, 
the 3 benches being sampled and analyzed separately: 
