NIOSHTIC-2 Publications Search
Shield design, construction and operation.
Barczak-TM; Chekan-GJ; Babich-DR
Longwall USA, 1998 Jun; :5-47
The success of longwall mining can largely be traced to the development of shield support. The most obvious trend in shield design has been an increase in shield size and capacity. The other major improvement has been in electro-hydraulic control technologies. This paper examines these design practices in relation to shield selection and capacity determination philosophies, and the consequences of these design practices on capability of the longwall shield to provide effective ground control. Issues related to the setting loads and support stiffness are discussed in detail. Laboratory performance testing of shields can be critical to a successful new shield design and invaluable in assessing the life expectancy of aging shields. NIOSH has recently opened its Safety Structures Testing facility at the Pittsburgh Research Laboratory for shield performance testing, providing unique capabilities using the Mine Roof Simulator (MRS) load frame. Retirement criteria for aging longwall shields are examined and factors that lead to premature failure of shields are discussed. Hydraulic problems are experienced by virtually every longwall shield at some point in their operating life. These hydraulic problems can result in no support capacity, yet many hydraulic failures go undetected since the leaks are internal to the leg cylinders. Methods to identify and diagnose these hydraulic problems are provided in the report. In summary, this paper provides a good overview of the issues that impact the design, construction, and operation of modern longwall shields.
Underground-mining; Mine-safety; Mining-equipment; Hydraulic-equipment; Mine-safety; Mining-industry
National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, Pittsburgh, PA
Other Occupational Concerns
Longwall USA, International Exhibition & Conference