Underground » Maintenance
In coal mining operations, materials handling constitutes a major component of the production costs. Belt conveyors play a central role in the mining, processing, storage and transportation of coal. It is essential that they operate efficiently with maximum availability and with a minimum of down-time.
Conveyor reliability and availability is of paramount importance in the case of drift conveyors considering the major capital investment in long wall mining equipment.
While the technology of belt conveyors and the associated design procedures have been making significant advances, there are areas several areas associated with existing conveyors where the performance is less than desirable. This is largely due to reduced component life and inadequate maintenance management strategies.
Part of the problem may have been the fact that materials handling, of which belt conveying is a major component, has often been viewed as 'beginning where the process ends' and hence, not adding value to the product.
In view of the high cost of handling in mining operations, often more than 50% of the selling price, nothing could be further from the truth. Incremental gains in reliability and efficiency of handling operations can lead to significant reductions in costs. It is an indirect, but very positive form, of 'value adding'.
The objectives of the project are summarised below:
- Quantify the cost of conveyor downtime
- Identify specific problems which are leading to reduced conveyor system availability
- Conduct research and provide recommendations aimed at solving the problems identified in the point above
- Increase the knowledge of site personnel of conveyor system design and operation, and raise awareness regarding the availability of assistance with solutions.
- Form a data base of field information against which improvements in system reliability can be measured.
Early in the program it became apparent that an effective maintenance policy is totally dependant on the availability of reliable condition monitoring equipment and procedures.
This is essential for the identification of the cause of problems, permitting corrective action to be taken and improved design procedures to be initiated. Thus a major emphasis of the project has been given to condition monitoring.
Belt conveyor maintenance and reliability is broad ranging, touching on many aspects of conveyor design and operation. Based on background knowledge, supported by several field studies, an overall appraisal of conveyor maintenance and reliability has been undertaken. Several problem areas requiring attention have been identified. The importance of condition monitoring has been stressed and research aimed at improved performance through better design and associated condition monitoring has been undertaken.
Overall, the theory and practice of conveyor design has been extended by incorporating the findings of the re-search. In this way, the design of conveyors for more reliable operation is continually being improved.
This final report records the work of TUNRA over the past 3 years in investigating the cost and causes of conveyor down time.
A number of installations are analysed and important recommendations are presented as to how operators can overcome maintenance problems.
The report is divided into the following chapters:
- Conveyor System Maintenance and Reliability
- Measurement of Dynamic Tension Distribution
- Idler Reliability and Bearing Seal Performance
- Belt Condition Monitoring
- Coal & Conveyor Belt Interaction
- Conveyor Belt Cleaning & Carry Back Measurement
- Drive Drum Friction Investigation
- Coal Transfer Point Design