Reliability Analysis of Armored Face Conveyor (AFC) in Tabas Mechanized Coal Mine

Regarding the vital role of coal in power generation, many attempts have been made to increase the coal production. Nowadays, the extraction operation in many underground mines is done by fully mechanized methods. Therefore, determination and improvement of the machinery performance is very important. Armored Face Conveyor (AFC) is one of the most important machineries in underground mines, which has a direct effect on the production rate. Hence, reliability of this machine is very important. Here, the reliability of AFC machine has been analyzed using the 2 years’ failure data which had been collected from Tabas coal mine. Four subsystems were defined for this machine; electrical system, mechanical system, chain tension unit and speed control unit. Then, the data sets were examined to asses the existence of trend and serial correlation. The best distribution function was selected based on the result of various statistical processes. The results show that the electrical and chain tension units obey the power low model and mechanical system has the 3-parametrs Gamma reliability function. The speed control unit obeys the 4-parameters Gamma Generalized distribution and the reliability of whole machine decrease to almost zero after 120 operation hours. Preventive maintenance based on the reliability interval of 80% was calculated for AFC subsystems. It is suggested that the electrical system, mechanical system, chain tension unit and speed control unit should be checked and serviced every 1, 20, 20, 10 hours respectively.