Mining Project: Design Procedures for Gateroad Ground Control

Keywords: Ground control
Principal Investigator
Start Date 10/1/2014
Objective

To develop engineering-based procedures that will contribute to the practical design of ground control systems in gateroad excavations and longwall extractions.

Topic Area

Research Summary

Underground coal miners working in longwall mines face hazards from major roof collapses that can block necessary escape routes and ventilation airways, and from injuries from falls of smaller volumes of rock and coal. The blockage of ventilation airways has the potential to lead to gob combustion, an extremely hazardous and unacceptable outcome.

To reduce these hazards, this project has three research aims, as follows:

  1. Quantify rock-support interaction in gateroads subject to longwall loading.
  2. Identify critical parameters affecting gateroad stability.
  3. Develop and test practical design procedures for gateroad ground control.

This project will develop engineering-based procedures that will contribute to the practical design of ground control systems in gateroad excavations and longwall extractions. Design guidelines, methods, and best practices will be developed to reduce the quantity and severity of ground instabilities due to longwall extraction. The  design procedures will be developed through numerical modeling, statistical analysis, and back analysis of historic events.

The research approach will include in-mine monitoring studies, laboratory testing to quantify rock properties, full-scale support testing to characterize current and new standing support systems, numerical analysis of rock-support interaction under changing loading conditions, analysis of support alternatives, and finally the development of practical design procedures based on sound engineering principles. The goal is to reduce unplanned ground instabilities in longwall mines by at least 35%.

Several in-mine monitoring studies to measure ground and support system responses have been completed, or are underway, at collaborating mines in West Virginia, Pennsylvania, Alabama, Virginia, Wyoming, and Utah. Data from these study sites are being used to better understand the mechanics of ground stress, deformation of gateroads, and the contribution of different support types to overall stability. The results form the basis for developing engineering-based procedures for analyzing various gateroad ground control options. Preliminary results have been published and are listed in the “Related Publications” list below.

The impact of the developed design and analysis procedures will be a reduction in the frequency and severity of injuries due to longwall gateroad instabilities. The level of reduction in injuries will vary by mining conditions, but in many cases the resulting longwall gateroad stability will eliminate the disruption to the ventilation system.

Related Publications

Analysis of global and local stress changes in a longwall gateroad

Analysis of monitored ground support and rock mass response in a longwall tailgate entry

Changes in stress and displacement caused by longwall panel retreats

Overview of current US longwall gateroad support practices

Verification of a calibrated longwall model with field measurements

Application of a brittle failure model to assess roof stability in coal mine entries

Application of the strength reduction method in coal mine roof support design


Page last reviewed: 3/7/2019 Page last updated: 10/22/2016