Design and Construction Considerations for a Protected Compressed Air Line to a Refuge Alternative

One of the most important issues related to refuge alternatives in underground coal mines is the ability to provide breathable air to the refuge area after a catastrophe. A refuge alternative is defined as a protected, secure space with an isolated atmosphere and integrated components which create a life-sustaining environment for persons trapped in an underground mine when escape is impossible (30 CFR Part 7). For permanent and semi-permanent refuge areas, the breathable air is supplied to the refuge alternative by compressed air from cylinders, fans, or compressors installed at the surface. The advantage of air supply through fans or compressors installed at the surface is the unlimited supply of air to the refuge. When breathable air is supplied using fans or compressors installed at the surface, it is necessary to use compressed air lines. To guarantee the success of the system and maintain a safe atmosphere for the trapped miners, the integrity of the compressed air line must be kept all times. Current requirements for design and construction of compressed air lines are general and there are not detailed guidelines and specifications. During design and construction of refuge alternatives, several questions emerge regarding protected compressed air lines. This research will explore, in a practical way through laboratory tests, the most important design and construction considerations regarding compressed air lines to a refuge alternative including; materials for compressed air lines, bending strength requirements, anchoring systems, protection of the lines and drainage. Four main task are included in the proposal: „h An extensive landscape assessment of commercially available compressors will be conducted to determine appropriate requirements for compressors, „h Several tests will be developed in the lab, using pipes of different type of materials (Carbon steel, Alloy steel and Stainless steel). The specimen will be subject to repetitive (dynamic) bending loads to simulate working conditions and against explosions. Different anchoring techniques will also be tested. „h The connections between sections of the compressed airline will be tested to define the design and construction specifications, „h Upon completion of the lab testing phase of the project, recommendations will be prepared for implementation of compressed air lines in mining environments.