DEMONSTRATION OF A NOVEL ROOF BOLT DESIGN FOR IMPROVED ROCK MASS STABILITY
Title
DEMONSTRATION OF A NOVEL ROOF BOLT DESIGN FOR IMPROVED ROCK MASS STABILITY
ICCI Project ID
15/3A-1
Investigator
Chugh
Institution
Southern Illinois University
ICCI Abstract
An ongoing ICCI study is attempting to assess current support systems and develop support guidelines for coal mine intersections in partial extraction and longwall mining systems. In the study the project team had hypothesized that supports at intersections should: 1) Provide high initial support stiffness to immediate roof and floor strata around corners and centers of intersections to be self-supporting and transfer loads into pillars, 2) Allow controlled yielding of rock mass with moderately increasing stiffness that would contribute to rock mass reinforcement. A review of currently used bolting systems has indicated that such characteristics are not available at reasonable cost to consumer.
As part of the ongoing project, a novel roof bolt design has been conceived by the PI that has potential to significantly improve rock mass stability at coal mining intersections and other areas. It has been subjected to limited laboratory SEPT testing in concrete block. For the selected bolt design and as compared to a currently used # 7 rebar passive roof bolt: 1) Its initial stiffness was 5-6 times larger, 2) Its stiffness over the entire range of loading was about 2-3 times larger, and 3) It sustained load better in the high load range areas. In limited side-by-side SEPT field testing of two (2) conventional and five novel bolts using # 6 rebar passive bolt in an Illinois coal mine, the relativeness stiffness over the entire loading range was about 1.4 times the conventional passive rebar bolt. The collaborator (DSI Underground) is very enthusiastic to commercialize it.
This proposal will design the bolt for commercialization and develop laboratory and field data for approval from MSHA. The data will include rock mass movement data in field at coal mine intersections and entries in room-and-pillar mining and longwall development entries for a period of 2-3 months for both conventional bolts and the novel bolt. The data will include roof-to-floor convergence and roof bolt loading data.
As part of the ongoing project, a novel roof bolt design has been conceived by the PI that has potential to significantly improve rock mass stability at coal mining intersections and other areas. It has been subjected to limited laboratory SEPT testing in concrete block. For the selected bolt design and as compared to a currently used # 7 rebar passive roof bolt: 1) Its initial stiffness was 5-6 times larger, 2) Its stiffness over the entire range of loading was about 2-3 times larger, and 3) It sustained load better in the high load range areas. In limited side-by-side SEPT field testing of two (2) conventional and five novel bolts using # 6 rebar passive bolt in an Illinois coal mine, the relativeness stiffness over the entire loading range was about 1.4 times the conventional passive rebar bolt. The collaborator (DSI Underground) is very enthusiastic to commercialize it.
This proposal will design the bolt for commercialization and develop laboratory and field data for approval from MSHA. The data will include rock mass movement data in field at coal mine intersections and entries in room-and-pillar mining and longwall development entries for a period of 2-3 months for both conventional bolts and the novel bolt. The data will include roof-to-floor convergence and roof bolt loading data.
Start Date
1/1/2015
End Date
7/31/2016
Year Funded
2015
Manager
Joe Hirschi
Collection
Citation
“DEMONSTRATION OF A NOVEL ROOF BOLT DESIGN FOR IMPROVED ROCK MASS STABILITY,” ICCI Reports, accessed May 20, 2024, https://isgswikis.web.illinois.edu/icci_reports/items/show/856.