ICGCM Papers:
Operator Case Histories
 
 
The Development and Planning of Multiple Level Underground Limestone Mines
35th International Conference on Ground Control in Mining
The Development and Planning of Multiple Level Underground Limestone Mines
by
David A Newman, Appalachian Mining & Engineering, Inc., Fayette, United StatesBruce W King, Rogers Group, Inc., Nashville, United States
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[Conference] 35th International Conference on Ground Control in Mining
[Price] Free  [Comments] 0
[Topical Area] Operator Case Histories
[Author] David A Newman, Appalachian Mining & Engineering, Inc., Fayette, United StatesBruce W King, Rogers Group, Inc., Nashville, United States
[Abstract] 
Key Conclusions:
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A multiple level underground quarry must be planned in total and not level by level. The geology encountered on an upper level likely will affect those below it and therefore in-mine and in-pit mapping must accompany exploration drilling. An error or poor decision on one level adversely affect those below it.
Key Findings:
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A poor choice for the back horizon in the Tyrone adversely affected the back horizon in the underlying Camp Nelson limestone. Numerical modeling demonstrated that the sill pillar separating the base of the Tyrone level with the preferred Camp Nelson is too thin for long term stability. The Camp Nelson pillars cannot be columnized with those in the overlying Tyrone level due to a difference in mining height and overburden excess of 1,000-feet. Although the three levels in the Hermitage and Carters can be columnized, the third level in the Carters Limestone had to be modified to accommodate stress transfer from the overlying levels.
Objective of the Paper:
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The objective of the paper is to present case histories of multiple level mine planning in the Tyrone-Camp Nelson and Hermitage-Carters-Lebanon-Ridley Limestones. The case histories document detailed exploration drilling, geological characterization, in-pit survey correlation with the geologic logging, strength and physical property testing, analytical analysis, and numerical modeling were combined to plan multiple level underground quarries.
Problem Statement:
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Once surface limestone reserves are either exhausted or inaccessible, an quarry operator must develop underground. Limestone reserves are frequently thick enough for multiple levels. The planning and design of a multi-level underground quarry involves geology, quality, and rock mechanics. The decisions made for the portal location and in the upper level affect subsequent levels and the entirety of the reserve. Historically underground quarries have been planned one level at a time. Geology, rock properties, and rock mechanics were not an integral part of the design that relied on prior practice at other quarries. This approach to underground quarry design has resulted in ground control problems in the upper level and underlying levels addition to reserve sterilization.