ICGCM Papers:
Advancements in Ground Control Instrumentation
 
 
Introduction to Rock Strength Borehole Probe (RSBP) for Estimation of Rock Strength in Roofbolt Drill Holes
35th International Conference on Ground Control in Mining
Introduction to Rock Strength Borehole Probe (RSBP) for Estimation of Rock Strength in Roofbolt Drill Holes
by
Ali NaeimipourJamal Rostami, Penn State University, University Park, United StatesI. Sedat Buyuksagis, Afyon Kocatepe University, Afyon, Turkey
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[Conference] 35th International Conference on Ground Control in Mining
[Price] Free  [Comments] 0
[Topical Area] Advancements in Ground Control Instrumentation
[Author] Ali NaeimipourJamal Rostami, Penn State University, University Park, United StatesI. Sedat Buyuksagis, Afyon Kocatepe University, Afyon, Turkey
[Abstract] 
Key Conclusions:
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Laboratory studies for estimation of intact rock strength by scratching the surface of the rock are shown to be promising and can pave the way to develop a scratch borehole probe. This device can be an effective, quick, no disruptive, cost effective alternative to estimate the rock strength inside the boreholes in underground mines and spaces.
Key Findings:
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The studies show a good correlation, with R-square values of around %80, between the normal force of scratching and the uniaxial Compressive Strength (UCS) and tensile strengths (BTS) of the sedimentary/metamorphic rocks. However, no significant correlation was generally observed for igneous rocks. General equations were also developed to estimate the UCS and BTS of sedimentary/metamorphic rocks by average normal force and cutting depth with reasonably good correlations. A probe based on this concept has been designed and fabricated and is undergoing its lab and field trials.
Objective of the Paper:
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This paper will discuss the necessity to develop such a probe and steps taken to develop the preliminary design of rock strength measurement probe. Results of laboratory studies to estimate the strength of various sedimentary, igneous and metamorphic rocks from scratching their surface with a miniature disc scribe will be covered. This includes introducing the developed scratch test machine, the test procedure, and results of the tests on 27 different rocks covering a wide range of strengths, grain size, and origins. The study will show the success of this approach in estimating the strength rock from cutting forces.
Problem Statement:
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Improvement in safety of underground openings along with optimization of ground support system requires reliable ground characterization. This includes understanding of the joints and discontinuities and rock strength. Joint information can be obtained from borehole cameras but measurement of in situ rock strength is very difficult. Borehole probing is an efficient way to meet this requirement and this paper will discuss the result of initial testing on a probe recently developed to measure rock strength from within the holes drilled for roof bolting.