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Research into the interpretation of deformation measured by extensometers

Date

2020-01-29

Journal Title

Journal ISSN

Volume Title

Publisher

ORCID

0000-0002-5337-727X

Type

Thesis

Degree Level

Masters

Abstract

This thesis interprets data collected by extensometers installed to monitor underground excavations in open stope mining environments. The interpretation of the extensometer data includes assessment of the measurements to determine the validity of the data and if the measurements are suitable for use in estimation of stress and/ or a geometry of potential instability. A new method for estimating a change in stress based on the elastic properties of the rock mass and the measured strains is introduced and applied. This method can be applied to estimate the pre-mining stress, normal to an opening, based on the normal strain caused by mining. The recently developed Strain Effective Radius Factor (SERF) method for estimating a potential geometry of instability is reviewed and applied to additional datasets. The SERF method is an empirical tool that can be applied to predict unstable stope hanging wall geometries based on trends in strain measurements. This is a useful development for interpreting the meaning of increasing hanging wall deformation and can provide insights into potential risks of continued stope excavation. This research interprets historic instrumentation datasets from two mining operations and introduces and analyzes a new instrumentation dataset from the Santoy mine in northern Saskatchewan. The two historical instrumentation datasets included stopes with hanging wall instability allowing the estimation of both pre-mining stress and a geometry of instability. The new instrumentation dataset monitored hanging walls without any recorded instability, therefore only the pre-mining stress could be estimated. It was found that pre mining stress could be reasonably estimated. A variation to the SERF method is proposed to improve the prediction of a geometry of instability and appears promising based on its application to a limited number of case histories.

Description

Keywords

Rock mechanics, Open stope, SERF, Hanging wall, Extensometer, Stress

Citation

Degree

Master of Science (M.Sc.)

Department

Civil and Geological Engineering

Program

Civil Engineering

Citation

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DOI

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