Bump control design protocol for room-and-pillar coal mining.
Campoli-AA; Mucho-TP; Zipf-RK Jr.
Proceedings: Mechanics and Mitigation of Violent Failure in Coal and Hard-Rock Mines. Washington, DC: U.S. Bureau of Mines, 1995 May; :181-199
The U.S. Bureau of Mines (USBM) developed a stress control design protocol to minimize coal mine bumps, the violent failure of overly stressed coal pillars. The protocol was developed for room-and-pillar retreat mining conducted with available continuous miner technology. A model of pseudoductile coal pillar strength was used to develop unlimited-width and limited-width section design criteria. The unlimited-width design assumes an infinitely long pillar line composed of uniformly sized pillars extracted against an infinitely wide gob area. Tributary-area theory was combined with a linear shear-angle concept to estimate loads applied to total-extraction pillars adjacent to gob areas. Overburden increases eventually prohibit unlimited-width sections and force the use of barrier pillars between limited-width sections. The USBM developed boundary-element code MULSIM/NL was used to develop and implement a systematic limited-width section design procedure. The complex distribution of gob-side abutment load between side abutment pillars and chain pillars in the total-extraction zone necessitated computer simulation. The USBM created a spreadsheet program, LAYOUT, to summarize and provide for efficient utilization of the bump control design protocol. Based on overburden thickness, coalbed thickness, and coal pillar dimensions entered by the user, LAYOUT calculates a stability factor for the first and second pillar rows outby the expanding gob for unlimited-width sections. H overburden and coalbed thickness conditions do not allow an unlimited-width section design, LAYOUT suggests a limited-width design. LAYOUT results were verified against four case studies of coal mine bumps.
Mining-industry; Coal-mining; Rock-falls; Rock-bursts; Rock-mechanics; Underground-mining; Control-technology; Geology; Geophysics; Engineering-controls; Ground-control; Ground-stability; Computer-software
Book or book chapter
Maleki-H; Wopat-PF; Repsher-RC; Tuchman-RJ
Proceedings: Mechanics and Mitigation of Violent Failure in Coal and Hard-Rock Mines