Mining Project: Mine Roof Simulator (MRS) Laboratory

Research Summary

The primary purpose of this project was to operate and maintain the Mine Roof Simulator (MRS) laboratory which supports NIOSH Mining Program  projects, mainly in the Ground Control Branch. The facility includes the world-class MRS test machine which can exert 1,500 tons of vertical load over a 24-inch stroke and 800 tons of horizontal load over a 16-inch stroke. The upper and lower platens are 20 feet x 20 feet and the opening for the test article can be up to 16 feet tall. Tests were conducted to measure the response of standing and intrinsic roof support systems, mine ventilation stoppings and seals, and various other structural elements.

Tests in cooperation with standing support manufacturers were conducted to help in the development of new support technologies and to record the behavior of modified standing support systems. This data was added to the STOP in yearly updates, when applicable, and was also available to the Mine Safety and Health Administration (MSHA) Technical Support Roof Control Division, among others.

A lightweight rib support product to help prevent rolls of the rib was recently introduced, and this product was developed and improved by testing at the MRS. The capabilities of the MRS were also used to develop a test method for ventilation stoppings to supplement the requirements of the Code of Federal Regulations. A more recent addition to the laboratory was the capability for testing the strength of roof screen materials.

An effort for testing mine seals against the new MSHA requirements became a major focus in the laboratory in 2011 in support of a research project in the Disaster Prevention and Response Branch (DPRB). The purpose of the tests was to measure the capacity of several different seal materials in different simulated roof and floor conditions and to characterize the mode of failure of the structure or its components. The design of the fixture for these tests was built to withstand horizontal loads applied by the MRS of up to 450 tons.

The results of this test program were used to calibrate a model being developed in cooperation with the U.S. Army Corps of Engineers.