Multi-attribute failure analysis of coal cutting picks on longwall shearer machine

In this paper, the results of a comprehensive study on failures of coal shearer picks in Parvadeh coal mine in Iran has been carried out and the main mechanisms and causes for pick failures have been investigated. For this purpose, 33, worn-out picks were collected from mine for laboratory studies. A series of tests and measurements, including weight loss, 3D geometry analysis of wear, macroscopic, and SEM microscopic analysis, were conducted. The results showed that pick body wears, breakage of pick tip, slimming of pick body, and separation and removal of pick tip are the most frequent failure and wear mode of studied picks. It is also observed that due to the locking of some picks in their holders, the high level of stress is transferred through the pick body to its bottom. It finally damages the pick and destroys the pick location on the drum. Nevertheless, the main reasons for most of the identified failures are the ineffective rock breakage, which is caused by long spaces between the picks. Finally, some practical recommendations especially redesigning the drum and picks' configuration, are presented in the paper to enhance the lifetime of cutting picks of the studied shearer.