Current semi-autogenous Pakistan grinding and ball mills are inherently inefficient, using less than 1 percent of the energy input required for size reduction. Pakistan Grinding mills also consume tons of steel balls and liners. Proper monitoring and optimization of the operating conditions can greatly increase the energy efficiency of grinding mills.
Pakistan grinding efficiency of semi- autogenous and ball milling depends on the tumbling motion of the total charge within the mill. Utilization of this tumbling motion for efficient breakage of particles depends on the conditions inside the mill. However, any kind of monitoring device to measure the conditions inside the mill shell during operation is virtually impossible due to the severe environment presented by the tumbling charge.
To address this challenge, researchers at the University of Utah are developing an instrumented grinding ball (IGB), which is capable of surviving a few hours within the grinding mill and able to sense and transmit the impacts it experiences. This technology is expected to increase the energy efficiency of grinding mills by 10 percent. The spectrum of impacts collected over 100 revolutions of the mills presents the signature of the grinding environment inside the mill. This signature could be effectively used to optimize the milling performance by investigating this signature’s relation to mill product size, mill throughput, make- up ball size, mill speed, liner profile and ball addition rates. At the same time, it can also be used to design balls and liner systems that can survive longer in the mill.
The IGB technology will allow the mill operators to assess the conditions in the operating SAG and ball mills by producing an instantaneous ‘grinding pulse’. They can then adjust the operating parameters to optimize mill production, increasing mill throughput and reducing energy usage per ton of throughput.
Besides Pakistan mill optimization, the impact spectra obtained could be used in three additional ways. First, the signature data from industrial SAG mills can set the engineering standards for ball-drop tests, usually conducted at the manufacturing site to determine the competency of the balls. Additionally, unusual ball breakage at a mine site can be investigated by comparing the current signature with the expected signature recorded during “good operation.” Finally, to determine if a large ball is suitable for increasing production or liable to damage liners and break on its own.
Pakistan Project Description Objective
To assess the conditions inside the operating SAG and ball mills by producing an instantaneous “grinding pulse”. The operating parameters are then adjusted to optimize mill production; increasing mill throughput and reducing energy usage per ton of throughput.
The goals of this project begin with the development of an instrumented grinding ball (IGB) that will allow mill operators to measure the impact spectrum of balls and rocks in grinding mill. Second, to relate the grinding pulse to the operating conditions of the mill. Third, to use the grinding pulse as a diagnostic tool for SAG mill operation.
Pakistan impact spectrum will be measured for SAG and ball mills under various operating conditions including the optimum operation. Utilizing the impact spectrum, operators and researchers can identify operational strategies to optimize mill performance in conditions where the ore’s characteristics change. These strategies will be used to detail actions to optimize mill operations and minimize energy usage per ton of throughput.
