Masters Theses

Abstract

"The degree of fragmentation and the level of ground vibration from a bench blast employing standard full-column completely-coupled explosive charges are commonly controlled by varying one or more of the many dimensional variables of blast design. Blasting techniques such as decoupling and air-gapping, utilizing air space in the blasthole, have also been reported as having the potential to control rock fragmentation and ground vibration.

This investigation, using reduced-scale in situ bench blasts, examined the degree of fragmentation and the level of ground vibrations produced from the standard full-column completely-coupled, air-gapped, and decoupled methods of blasting to:

1. Compare the effectiveness of decoupled and air-gapped blasting for controlling fragmentation and ground vibrations;

2. Evaluate air-gapped blasting relative to the standard full- column completely-coupled method of blasting on the basis of fragmentation and ground vibration; and

3. Identify the more dominant of the two borehole phenomena that vary under decoupling conditions -- energy transfer and effective bore- mole pressure -- with respect to their influence on fragmentation.

It was found that air-gapping and decoupling had equal ability to control fragmentation and ground vibration at the same air-to-explosive volume ratio, and that the standard full-column completely-coupled method produced a higher degree of fragmentation and level of ground vibration than the air-gapped method of blasting. Furthermore, it was found that effective borehole pressure had a greater influence on fragmentation than energy transfer"--Abstract, page ii.

Advisor(s)

Smith, Norman

Committee Member(s)

Elifrits, C. Dale
Haas, Charles J.

Department(s)

Mining Engineering

Degree Name

M.S. in Mining Engineering

Comments

Many thanks are extended to the Department of Mining Engineering of the University of Missouri--Rolla and the Ensign-Bickford Company for their financial support in the preparation of this thesis, and to the Atlas Powder Company for providing the explosives used in this study.

Publisher

University of Missouri--Rolla

Publication Date

Fall 1984

Pagination

xi, 92 pages

Note about bibliography

Includes bibliographical references (pages 57-60).

Rights

© 1984 Everett Ellsworth Bleakney III, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 5118

Print OCLC #

11589909

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