Underhand longwall program at Lucky Friday Mine, Mullan, ID.
Authors
Poad-ME; Johnson-G; Whyatt-JK; Hoskins-JR
Source
Proceedings: Mechanics and Mitigation of Violent Failure in Coal and Hard-Rock Mines. Washington, DC: U.S. Bureau of Mines, 1995 May; :335-346
Abstract
Researchers from the U.S. Bureau of Mines (USBM) have been investigating alternative mining methods to reduce the number and severity of mining-induced seismic events in the deep mines of the Coeur d'Alene Mining District of northern Idaho. In 1984, USBM entered into a three-way memorandum of agreement with Hecla Mining Co., Mullan, ID, and the University of Idaho, Moscow, ID, to design, implement, and evaluate a mining system that could be used safely and productively for vein mining in a rock-burst-prone mine. A mechanized underhand longwall cut-and-fill method using a ramp system for access was chosen for study at the Lucky Friday Mine, Mullan, ID. A 122-m (400-ft) long test stope was developed between the 5100 and 5300 levels. In the underhand method, a block of ground is mined from the top down in a single advancing face, always toward virgin ground; this procedure eliminates the development of a highly stressed sill pillar. Because an engineered fill is placed after each cut, a more competent back is created for the next cycle. Success of the test stope led to adoption of the underhand longwall as the primary mining method throughout the mine.
Keywords
Mining-industry; Rock-falls; Rock-bursts; Rock-mechanics; Underground-mining; Control-technology; Geology; Geophysics; Engineering-controls; Ground-control; Ground-stability
Document Type
Book or book chapter
Editors
Maleki-H; Wopat-PF; Repsher-RC; Tuchman-RJ
Source Name
Proceedings: Mechanics and Mitigation of Violent Failure in Coal and Hard-Rock Mines