Investigation of the Effect of Various Parameters on the Ore Hardness of Gole-Gohar’s No. 1 Mine

Attention to the hardness of ores and their grindability is increasing due to the importance of energy consumption. In this study, 73 samples of iron ore were prepared from Gole-Gohar’s No. 1 mine, and the SAG power index test was performed to measure hardness. The distribution of the hardness values of these samples and its comparison with the results of the last five years showed a significant increase in the hardness of the mine so that the average hardness increased from 32.1 minutes to 65.6 minutes. In addition, the hardness distribution of Gole-Gohar mine demonstrated that 52%, 26%, and 22% of the ore were obtained with a hardness of less than 50 minutes (soft materials), 50-100 minutes (medium), and more than 100 minutes (hard), respectively. Among the hardness-related parameters, the total Fe, S, Fe/FeO ratio, density, and magnetite recovery in the Davis tube test had no significant relationship with hardness, indicating the special importance of homogenizing the feed to the processing plant based on ore hardness in addition to grade homogenization. However, mineralogical factors such as texture, the composition of the constituent minerals, and the type and frequency of the constituent minerals have a significant effect on the hardness of the samples.