Cherchar Abrasion Test Study

The Pennsylvania State University The Graduate School Department of Energy and Mineral Engineering

STUDY OF CERCHAR ABRASIVITY INDEX AND POTENTIAL MODIFICATIONS FOR MORE CONSISTENT MEASUREMENT OF ROCK ABRASION

A Thesis in Energy and Mineral Engineering by Amirreza Ghasemi

 2010 Amirreza Ghasemi

Submitted in Partial Fulfillment of the Requirements for the Degree of

Master of Science

August 2010

The thesis of Amirreza Ghasemi was reviewed and approved* by the following:

Jamal Rostami Assistant Professor of Energy and Mineral Engineering Thesis Advisor

Derek Elsworth Professor of Energy and Mineral Engineering

Robert L. Grayson Professor of Energy and Mineral Engineering Head of the Graduate Program

*Signatures are on file in the Graduate School

iii ABSTRACT Tool wear is an important parameter in mechanized tunneling and is highly affected by rock abrasiveness. There are numerous tests to identify the rock abrasivity. One of the widely used rock abrasion tests is the Cerchar abrasion index (CAI). This test is used for estimation of bit life and wear in various mining and tunneling applications. The test is simple and can be considered for field applications. However, there are some discrepancies in the test results related to the equipment used, surface condition of rock samples, operator skills, and procedures used in measurement of worn out surface (wear flat). This study discusses the background of the test, reviews the testing parameters and their impact on testing as noted in previous studies, and examines the impact of the different parameters on Cerchar testing. Seven rock types ranging from abrasive to non-abrasive were in the testing program. Pins with different hardness were used on rough and sawn surfaces of the selected rock samples. Geomechanical properties of these samples were also measured. Cerchar values of different pins were compared and formulas offered by some researchers for conversion of the CAI measurements between pins of

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