Mine production systems are complex and they depend upon several sections of equipment. A breakdown or stoppage on one equipment section will almost always cause other sections to come to a halt. It is at this point when the production cost / tonne of mined material starts to rise significantly and true efficiency is lost.
Conveyors, transfer points, crushers, skip loading and hoisting sections are some of the many elements in the material handling system that may represent single points of failure and cause the cutting machinery to be stopped.
Condition monitoring of the mechanical elements, through the sensing of vibration and temperature, for example, enables preventative maintenance. Advances in compact intrinsically safe (IS) monitoring systems coupled with mine communications networks that can transport data quickly around the mine up to the management system make preventative maintenance increasingly more effective as a tool to maximise production.
Remote monitoring of the electrical systems to analyse why faults have occurred can prove more problematic.
Frequently, the stoppages happen for the same reason over and over again. To resume production as quickly as possible, drives, circuit breakers and other elements of the electrical system are reset - but often the root-cause of the problem is either not identified or just accepted as ‘one of those things that happens as part of the production routine.’
To get a grip on these problems requires data to be captured rapidly to work out what happened first after a fault has occurred. Of course, the biggest gains come from preventing a fault, or ‘trip’, from occurring in the first place, which is what good mine production monitoring systems are all about.
Experience with coal production monitoring systems completed in recent years shows that by monitoring the currents on the main motors of cutting machinery, and keeping them on the right side of the ‘red line’, can produce significant increases in tonnage / shift compared to cutting too deeply or too fast. The production lost due to trips arising from over cutting outweighs any short-tem gains.
The technical challenge lies in finding ways to extract the data from the electrical systems of different manufacturers’ equipment. Few companies would want to replace whole sections of equipment with the sole aim of adding a modern monitoring system.
For example, part of the technical challenge is to extract data from within equipment employing flameproof (FLP) explosion protection techniques and transfer this safely into IS systems as a retrofit solution.
A whole range of technical advances in the IS monitoring systems and interfacing techniques now make this an entirely practical and affordable proposition.
Combining monitored information from both mechanical and electrical system elements onto a common data highway is a powerful tool in the battle to reduce the cost of production and increase efficiency.
Written by Steve Clayton, Managing Director, Promtex Ltd., Trolex representative for Russia.
Read the article online at: https://www.hydrocarbonengineering.com/special-reports/25072013/coal_mine_production_monitoring_019/