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Examination of design and operation practices for longwall shields.

Authors
Barczak-TM
Source
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, IC 9320, 1992 Jan; :1-14
NIOSHTIC No.
10011402
Abstract
The success of longwall mining can largely be traced to the development of powered roof support systems. The most significant improvement in powered support design has been the shield support, which improved kinematic stability and promoted the application of longwall mining in difficult-to-control caving conditions where chock and frame supports were inadequate. The most obvious trend in shield design has been an increase in shield size and capacity. This U.S. Bureau of Mines report examines shield design and operation practices and their consequences for the utilization of high-capacity shield support systems. An optimization goal is to minimize support loading by selecting an active shield setting force that is compatible with strata behavior and shield loading characteristics. Shield stiffness is an important design parameter that is often overlooked. A consequence of increasing shield capacity by incorporating larger diameter p g cylinders is a proportional increase in shield stiffness. Setting forces have also increased in direct proportion to the increase in shield capacity. The increased stiffness and higher setting force cause the available capacity to be consumed more quickly, severely limiting the ability of high-capacity supports to last longer and provide reserve capacity for difficult mining conditions.
Keywords
Mining-industry; Coal-mining; Underground-mining; Longwall-mining; Mine-roof-support
Contact
National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Publication Date
19920101
Document Type
Information Circular
Fiscal Year
1992
NTIS Accession No.
PB2004-100297
NTIS Price
A03
Identifying No.
IC-9320
NIOSH Division
PRC
Source Name
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, IC 9320
State
PA
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