MINING CONDITIONS UNDER CITY OF SCRANTON, PA.
86
TEST NO. 8.
In this test a cast-iron cylinder was filled with coal culm flushed in with water. A piston was then placed on top of the culm and the whole was allowed to stand on a boiler for two days; the cylinder was then placed in the testing machine and pressure was applied to the piston, which in turn communicated the pressure to the culm, within the cylinder. The inside dimensions of the cylinder were as follows: Diameter, 6f inches; depth, 10J inches. The depth of the culm in the cylinder was 10 inches. The pressure was applied to the piston and the culm was compressed until the settlement reached 2.7 inches under a load of 200,000 pounds. This load corresponds to a pressure of 6,150 pounds per square inch or 443 short tons per square foot. The loads and settlements are given in the following table:
Loads and settlements of wet coal culm confined in a cast-iron cylinder.
Loads.	Settle- ments.	Loads.	Settle- ments.	Loads.	Settle- ments.
Pounds. 100 1,100 2,100 3.100 4.100 5.100 6.100 7.100 8.100 9,100	Inches. 0.10 .19 .27 .32 .36 .43 .58 .63	Pounds. 10,100 12,100 14.100 16.100 18,100 20,100 25.100 30.100 35.100 45,000	Inches. 0.66 .76 .85 .93 1.01 1.07 1.22 1.34 1.45 1.66	Pounds. 55.400 65.000 75.000 85.400 95.000 106,300 124,670 150.000 200.000	Inches. 1.82 1.94 2.04 2.13 2.21 2.32 2.40 2.44 2.73
TEST NO. 9.
This test consisted in applying pressure to the piston of a cast-iron cylinder in the same manner as in test No. 8, but the cylinder was filled with broken dry sandstone instead of coal culm. This broken sandstone had 40 per cent voids, and the pieces would all pass through a ring If inches in diameter. The cylinder was filled to the top, giving a depth of stone of 10^ inches. The maximum load applied was 300,000 pounds, which caused a settlement of 3| inches, or 9,200 pounds per square inch . As a result of the test, the stone was completely crushed and compressed into the iron cylinder so that it had to be cut out with a chisel. The loads and settlements for this test follow:
Loads and settlements of broken sandstone confined in a cast-iron cylinder.
Loads.	Settle- ments.	Loads.	Settle- ments.	Loads.	Settle- ments.
Pounds. 100 2,000 4.000 6.000 8,000 10,000 12,000 14,000	Inches. 0.46 .72 1.10 1.30 1.43 1.56 1.69	Pounds. 16,000 18,000 20,000 25.000 30,uOO 35.000 40.000 50.000	Inches. 1.79 1.89 1.94 2.15 2.32 2. 42 2.52 2.67	Pounds. 75,000 100,000 125.000 150.000 175.000 225.000 275.000 300.000	Inches. 2.91 3.07 3.18 3.28 3.35 3.51 3.55 3.56