Effects of Overused Top-hammer Drilling Bits

Abstract

The drill bits are the foremost common consumables in the mining industry but an essential part of the rock excavation process. The management of the bit wears directly influences the drilling quality and the productivity of the mine but often overlooked as a common consumable part. The study aims to analyze the effects of overused top-hammer drilling bits to various type of bit failure modes. 341 drill bits samples (ST68-102mm) were visually investigated to check the status of overused and failures. The button chipped (BC) type of failure occurs most frequently among all other types of bit failures. Subsequently, a positive correlation between the number of grinding rounds and bit failures were found. In addition, a cost analysis was conducted to demonstrate the adverse effects of drilling with overused bits. The results explicitly show the cost loss of using overused bits as the cost per metre (CPM) of 75% flat bits calculated to 3.1 AUD per metre while the CPM stays at 1.6 AUD per metre for using rock bits with 30% flat buttons.