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The Ball Mill Abrasion (BMA) test was developed by the University of Queensland Materials Performance group to simulate the high stress abrasion conditions experienced in production ball mills. It gives accurate predictions of the service life of wear resistant alloys in mill liner and grinding media applications. In this paper the BMA test methodology was applied to investigate the wear rates of four grades of grinding media using two small laboratory ball mills. The rankings obtained from the tests were identical with those from the full BMA test, although the difference between the different grades was not as marked. It is concluded that untrained personnel can use a simple small-scale procedure to evaluate relative but not absolute grinding media wear rates..
The mining industry is searching for more energy efficient and dry comminution equipment as an alternative to conventional crushing followed by wet grinding circuits. This is a result of growing challenges associated with the increasing energy cost, scarcity of water resources and stricter environmental legislation. Dry comminution technologies, such as High Pressure Grinding Rolls (HPGR) and Vertical Roller Mills (VRM), have been successfully used in other industries such as cement and coal for decades, and the literature claims that these technologies are more energy efficient than conventional comminution practices. Pilot scale testing was conducted for each of these technologies using rock with properties similar to many mineral ores to test the claims in the literature and evaluate the applicability for hard rock mining operations. Whilst the test results for the HPGR and VRM are not directly comparable (due to different degree of size reduction), both demonstrated the potential for considerable energy savings compared to conventional ball milling. The HPGR and air classification circuit used 20 – 30 % less energy than the HGPR, screen, ball mill circuit. While VRM was estimated to use 10 – 30 % less energy (depending on the type of VRM) than a ball mill circuit for a similar degree of comminution.
Lane Algorithm is used to determine optimum cut off grade for a mining operation. There may be three parts in each operation: mining, concentration and refining. In Sarcheshmeh Copper Mine the concentrate coming from the stock has the average grade in addition to the production rate and cost. Therefore, the grade distribution is affected by production rate and cost parameters. The calculation of the cut off grade is done using a modified Lane Algorithm. Therefore, a mix of blending stock received from outside and the concentrate from the mine was considered in the Lane Algorithm. Initially, the profit objective function was taken into account with the addition of the stock limitations; then, the Lane Quartet Model was used and the cut off grade determined. The model uses the technical and economical data of different parts to determine the cut off grade. The result of the model was a cut off grade of (0.1408%), which brings about an increase of 848051645 US dollars as profit, in comparison to the cut off grade (0.1617%) that was obtained by the Lane tripartite model.
This paper focus on the design, development and testing two type of synthetic based drilling fluid include of amine-treated Quebracho agent and Polymeric Fluid Loss agent. Amine-treated Quebracho agent is compatible with other chemical additives in Synthetic-Based Fluids and it shows high-temperature stability, low fluid losses and good Rheological properties. Traditionally invert emulsion drilling fluids have been used to optimize drilling performance primarily due to the high level of wellbore stability and high penetration rates shown while using these fluids. Invert emulsion fluids require various additives such as emulsifiers, fluid-los-control (FLC) agents, viscosifier etc. The paper includes the laboratory evaluation for high temperature application of two agents in invert emulsion drilling fluids.
This paper deals with the investigation of column leaching of low-grade ores from the copper mine Cerovo,
Serbia (the approximate Cu content in the ore ranges from 0.2 – 0.3 % with >10 % copper in the form of oxide minerals). The leaching experiments were performed using sulphuric acid solutions, whereby the kinetics of copper leaching was investigated with respect to acid concentration and solid to liquid ratio. The copper concentration in the leach solution ranged from 0.80 to 1.75 g dm -3 . The total Cu recovery rate ranged from 30 to 56 %, whereas the recovery rate of copper oxide minerals ranged from 67 to 100 %. Furthermore, with increasing the amount of liquid phase, copper recovery increases as well, and copper oxide minerals were completely leached out. Besides copper ions, considerably high ferrous/ferric ion concentrations were achieved in the leach solution. This concentration was sufficiently high for the use of either solvent extraction or ion exchange techniques or both for further treatment of the leach solution.
