The purpose of human resources management is not only to provide the labor effectiveness but also to consider the health and safety of the employees.  The research method used is a survey using quantitative-descriptive. The sampling was conducted by using a census method that is to make an observation to the entire population of 106 employees of PT. Vale Indonesia especially for the KILN Department and Calcine Transfer System as the respondents. The analysis used to test the hypothesis in this study is a statistical analysis of t-test, f-test, R2, the regression and path analysis. The calculation process was carried out using SPSS program package. The results show that the hypothesis of 1, 2, and 5 are received while the 3 and 4 are rejected. In other words, knowledge and monitoring have a positive and significant impact on safety but not directly and through the discipline as the intervening variable and the discipline also has positive and significant impact on the safety. It means that the higher the knowledge of the employees and the better the monitoring conducted, the higher the discipline of the employees that will give more positive impact on the improvement of the employees safety. 
Keywords: Knowledge, Monitoring, Occupational Discipline and Safety