Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 51-53).

Investigations were carried out to reach a comprehensive understanding of the action of the roof bolt together with its anchor, on the rock, and how this action helps in stabilising the roof in underground openings. Tests were conducted on a two dimensional photoelastic epoxy model, as well as on a limestone rock model. Results and their analysis revealed that, with the present design of the roof bolt, the most effective type of anchor is the one with the lowest-transverse force. Thus, the glue-anchored bolts are more effective than the expansion shell anchored ones. It was found that the expansion-shell-anchored bolts give high lateral compressive stresses around the anchor, longitudinal compressive stresses along the effective length of the bolt, and tensile lateral stresses in between the end bearing plates. The epoxy anchored standard bolts give no significant transverse compressive stresses around the anchors, nor between them, longitudinal compressive stresses along the effective length of the bolt, and lateral tensile stresses inbetween the end bearing plates. In practical application, the limitations imposed by present rock bolt designs inhibit the attainment of stress distribution patterns in accord with theoretical roof stabilisation principles. To increase the bolt efficiency in stabilising the roofs, a compressive device was found very useful in adding lateral compression to the surrounding stress field. This device can be used alone or fitted to rock bolts to induce compressive lateral stresses in zones where such stresses might help to form a stable roof. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xiv, 183 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 179-182).

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xiii, 167 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 139-143).

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xii, 84 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 83).

No description available.

Before the advent of the present day man equilibrium conditions had been established in many phases of nature. One of the phases which had reached this equilibrium condition was the coal and mineral deposits. As they stand, the stresses acting on coal and mineral deposits are in equilibrium,—any underground mining operation upsets this equilibrium. Shocks due to the unbalancing of stresses often time cause catastrophic roof-falls which kill and injure miners and damage equipment. Attempts are made to control these unbalanced stresses by choosing the proper method of mining and suitable method of roof support. About 20 years ago, the St. Joseph Lead Company in Missouri, in an attempt to get away from the awkward, bulky and expensive method of supporting roof by timber or steel and concrete, tried a new method of roof support.⁽¹⁷⁾ The new method was named “roof-bolting”. As the name implies, the lower exposed strata of the roof are bolted to the stronger less exposed strata above the mine opening. This new method has been used more and more in the past three years. At the present time over 200 companies are using this method of roof support.⁽¹⁶⁾ The roof bolting method of roof support has presented many problems which have to be solved before definite procedure for its use can be established. Some of these problems are: 1. How long should the bolt be. 2. At what angle should the bolt be inserted. 3. What should be the longitudinal and transverse center-to-center distance between the bolts. 4. What stress should be applied to the bolt when installed. 5. How often should the bolt be retightened. This thesis will be an attempt to solve some of these problems. / Master of Science

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xv, 214 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 92-94).

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xviii, 163 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 159-162).

No description available.