Mineral Processing
Reza Zolfaghari; Mohammad Karamoozian
Abstract
In flotation, entrainment (ENT) affects the recovery of the concentrate, and the entrainment model is often supposed to be only a function of particle size in models. Some research shows that other variables may also significantly affect ENT. In this study, some flotation experiments executed using a ...
Read More
In flotation, entrainment (ENT) affects the recovery of the concentrate, and the entrainment model is often supposed to be only a function of particle size in models. Some research shows that other variables may also significantly affect ENT. In this study, some flotation experiments executed using a mixture of pure quartz as the valuable mineral and a pure magnetite sample as the gangue mineral to investigate the effects of other variables, such as solid content, airflow rate, frother, and collector dosages, on ENT. The results showed ENT varied from 0.071 to 0.851 is different, while the entrainment recovery was between 0.006 to 0.23, which means that the difference is statistically significant. ENT affected by (1) collector dosage, (2) frother dosage, (3) solid content, (4) the interaction between airflow rate and solid content and, (5) the interaction between airflow rate and frother dosage. An empirical statistical model is presented based on operational parameters. As the present models for ENT incorporate just particle size, it is not enough to predict gangue recovery in industrial applications by keeping the operating conditions constant. This novel model can predict ENT based on different operational parameters. The developed model is presented based on the particle mass by changing the operation parameters.
H. Rasouli; K. Shahriar; H. Madani
Abstract
When longwall mining involves total extraction, it includes the overlying strata movements. In order to better control these movements, the height of fracturing (HoF) must be determined. HoF includes both the caved and continuous fractured zones, and represents the region of the broken ground whereby ...
Read More
When longwall mining involves total extraction, it includes the overlying strata movements. In order to better control these movements, the height of fracturing (HoF) must be determined. HoF includes both the caved and continuous fractured zones, and represents the region of the broken ground whereby a hydraulic connection to the mined seam occurs. Among the various empirical models for predicting HoF, the Ditton's geometry and geology models are widely used in the Australian coalfields. This work uses a case-based reasoning (CBR) method in order to predict HoF. The model's variables, including the panel width (W), cover depth (H), mining height (T), key stratum thickness (t), and its distance from the mined seam (y), are selected via the Buckingham's p-theorem. The data set consisting of 31 longwall panels is partitioned into the training and test subsets using the W/H ratio as the primary classifier of a semi-random partitioning method. This partitioning method overcomes the class imbalance and sample representativeness problems. A new CBR model presents a linear mathematical equation to predict HoF. The results obtained show that the presented model has a high coefficient of determination (= 0.99) and a low average error (AE = 8.44 m). The coefficient of determination for the CBR model is higher than that for the Ditton’s geometry (= 0.93) and geology (= 0.97) models. Contrary to the Ditton's models, the performance of the CBR model is consistent regarding the average and standard errors (AE and SE) of the training and test stages. The proposed model has an acceptable performance for all the width to depth ratios to predict HoF.
