Open Access

George Samuel Rice

• The report that follows gives the results of tests to deterrnine the compressive strength of artificial roof supports of various kinds used in the mining of anthracite in Pennsylvania. Some of the types tested also are used in bituminous coal mining in Pennsylvania and other parts of the United States. The report was rendered Bebruary 26, 1913, by the United States Bureau of Mines, then in the Interior Department, to the Pennsylvania State Anthracite Mine Cave Commission and was appended, without discussion, to the general report on mine caving made by that commission under date of March 1, 19 13, to the Governor and Legislature of Pennsylvanin. The commission's reporh remains unpublished. As numerous requests have been made for the test data obtained by the Bureau of Mines at its Pittsburgh Experiment Station in 1912-13 and as the data relate to the strength of artificial supports without reference to particular local places of application, they have permanent value in the designing of mine roof supports. It has therefore been deemed advisable to publish the results of the bureau's tests. In order that the reader may understand the reasons for makig these tests of roof supports and the procedure foIIowed by the Pennsylvania commission, its duties will be briefly described. The commission was created by an act of the Legislature of Pennsylvania, approved March 24, 1911, its members being appointed by the Governor of Pennsylvania under the terms of the act. There had been serious cave-ins of the surface in some of the cities and towns in the anthracite districts of Pennsylvania and particularly in the city of Scranton froin 1909 to 1911, destroying surface buildings, public and private, and seriously endangering life. ....