Early Warning of Longwall Weighting Events and Roof Cavities Using Lva Software

Hoyer, David I
Organization: International Conference on Ground Control in Mining
Pages: 7
Publication Date: Jan 1, 2011
It is shown that by monitoring longwall leg pressures in real time, warning can be given for significant weighting events and the formation of roof instabilities, such as roof cavities, several hours in advance. Longwall Visual Analysis (LVA) is a software package that continuously monitors shield pressures and shearer position in longwall mines. LVA has been running on 19 Australian longwalls for up to four years, and as a result a very substantial database of shield pressure trends in a wide range of longwall situations has been collected. This database has been analyzed to develop indicators that will give operators and geotechnical engineers advance warnings of developing conditions such as weighting events and difficult roof conditions. LVA displays live charts of data, such as shield leg pressures, loading rates, and yield frequencies. Data analysis techniques were applied to historical data records from multiple longwall sites in order to develop a ?Cavity Risk Index? (CRI). The CRI indicates the risk of roof cavities developing, and it is based on pressure trends that indicate significant yielding and loading rates spanning a region of relatively low support. Case studies from different longwalls are given, showing how the CRI can give real-time advance warning of the formation of roof cavities with their anticipated location on the face. The limited number of case studies done so far indicate that the predictions have a high degree of reliability, but more work is required to quantify this.
Full Article Download:
(2028 kb)


Additional chapters/articles from the SME-ICGCM book 30th International Conference on Ground Control in Mining

A Study on Geotechnical Risks in Interaction Between Open-Pi
Think Like a Rock
Mapping and Application of Roof Joint Patterns for Ground Co
The Autowarning Telltale: A New Safety Monitoring Device for
Recent Innovations for Slope Development
Analysis of Roof Falls at and Recommendation of Roof Control
The Introduction of Uk Rockbolting Technology into Coal Mine
A Pipeliner's Perspective on Longwall Mining
Why Dead Load Suspension Design for Roadway Roof Support Is
Investigation Into Abnormal Surface Subsidence Above a Longw
Protecting Underground Coal Miners From Rib Falls
MSHA Technical Review of Proposed Mine Designs for U.S.Under
Prediction of Roof Fall Rate in Coal Mines Using Fuzzy Logic
Surface Subsidence Velocity of Fully-Mechanized Thick Seam T
Engineering Geophysics - Mine Subsidence Risk Assessment Stu
A Retrospective on LaModel (Or Dr. Heasley?s Wild Ride)
Safe Pillar Extraction Practice - Some Geotechnical Principl
Case Study of Roof Behaviour and Conditions for Longwall Fac
Early Warning of Longwall Weighting Events and Roof Cavities
Streams and Longwall Coal Mining Subsidence: A Pennsylvania
Surface Structures Impacted By Subsidence From Pennsylvania
GIS Supported Evaluation of Surface Level Impacts Due to Aba
Development and Application of Impact-Resistant Lagging for
Detection and Monitoring of Surface Subsidence Associated wi
Applications of ARMPS (Version 6) to Practical Pillar Design
The Duncan Method of Partial Pillar Extraction at Tasman Min
The Duncan Method of Partial Pillar Extraction at Tasman Min
Geotechnical Considerations for Longwall Top Coal Caving at
Assessment of the Dynamic Loads Effect on Underground Mines
Designing Shotcrete As Primary Support in Tunnels
The Influence of Interface Friction and W/H Ratio on the Vio
Gateroad Support in the Czech and Polish Coal Mining Industr
Study on Eco-Friendly Underground Mining System for Ultra-Th
Ground Control Technology for Mass Exploitation of Coal Depo
The Initial Performance of Commonly Used Primary Support on
Application of Stress, Geologic, and Support Design System (
A Retrospective Assessment of Ground Control Research and Ap
Calculating the Mining-Induced Horizontal Deformation Indice
Understanding the Causes of Roof Control Problems on a Longw
The Technical Progress and Problems to Be Solved of Thick Co
Topography and Coal Seam Initial Stress Estimation: a Sensit
The Effects of Longwall Coal Mining on the Hydrogeology of S
Application of Yield-Lok Bolt for Bursting and Convergence G
Research on Mine Pessure Behaviors and Overlying Strata Move
Preventing Roof Fall Accidents - An Operation's Approac
Roof Bolting for Long-Term Entries in Underground Coal Mines
Numerical Modeling of the Pillar Confinement with Backfillin