Remote Health Monitoring for Mining Shovels
Access to real-time data allows timely diagnosis of problems
Mining shovels represent a significant capital investment. They are the workhorses for most open-pit mines and, whether it’s planned or not, mining companies can rarely afford to have them sit idle. When a shovel goes down unexpectedly, it has a huge impact on the operation.
P&H Mining Equipment Co. has been implementing a new Remote Health Monitoring (RHM) system, powered by the Matrikon Mobile Equipment Monitor system to gain real time feedback on shovel performance. The system offers the OEM a few new tools to help mine operators improve performance. It has already proven it can reduce the amount of downtime associated with an unplanned outage. The company also believes that it could identify design flaws and perhaps assist with operator training.
Although remote health monitoring has been around for a while, Curt Hanson, director-product management, P&H , explained that it is a new tool for the shovel OEM and they believe that it can reduce the mine’s cost per ton and help the mines operate more efficiently, especially when it comes to interfacing with the shovels in the field. “When a shovel goes down, it behooves us to try and protect these assets as much as we can, and to make sure that they are up and running as efficiently possible,” Hanson said.
As it is with all types of mining, remote locations are a challenge. Once a specialist does arrive on site, it’s difficult to troubleshoot a shovel while it operates. Some of the areas that the technicians need to see on these shovels are not easily accessible. “Basically, we have some important assets in tough locations and we needed to put tools in place that will help us make sure that they are running efficiently, and respond much faster when they are not,” Hanson said. “That enabler is remote health monitoring.”
Typically, when P&H gets the call that says a shovel is down, P&H MinePro Services is already onsite, diagnosing the symptoms, and trying to bring the shovel back to life. MinePro would engage the P&H product support team. Based on the magnitude of the problem, they would eventually seek help from the engineering team. An engineer would board a plane in Milwaukee destined for the mine, no matter where that may be. Then, a flurry of communication ensues until the shovel up and running again.
In the old days, Hanson explained, without the data surrounding the event, the P&H engineers were always guessing as to what had really happened. “We would rely on MinePro personnel to collect data and send it back to us,” Hanson said. “We would then try to recreate the situation in the lab.”
Remote health monitoring offers two distinct advantages. The data is waiting for the experts and the experts have access to the shovel from any location that has Internet access. A data logger is installed on the shovel and using a mobile equipment monitor application server, located in Milwaukee, the P&H engineers and MinePro specialists can get online and look at what’s happening in real time, diagnose the problem, and return the shovel to service.
The system improves responsiveness by allowing the experts to get to the root causes much more quickly. It provides a historical trend for temperatures, motor data, and fault data to review and diagnose issues. Being able to view data that were once unavailable, they can troubleshoot fault issues previously unrepeatable during machine testing. “We can look at faults and dial down into them looking at tags and trends associated with them,” Hanson said. “The fault log becomes correlated to a sequence of events and we can zero-in very quickly on the issue.”
The Dreaded Dipper Drop
A dipper drop can bring a shovel down for days and it’s a huge safety issue. Technically, a dipper drop is defined as the uncontrolled motion of the dipper dropping due to gravity. The suspended loads in the dipper can range up to 200 tons. In some cases, the shovel’s control system is able to regain control and stop the motion before damage is done. In other cases, the dipper stops when it hits the ground or--in a worst-case scenario--comes into contact with another piece of equipment. They occur for a variety of reasons, such as mechanical failure (brakes), electrical control system disruption, machine overloads, operator error, etc.
Within 24 hours of its installation on a shovel in a Wyoming coal mine, the Remote Health Monitoring system provided Brian Raba, regional product specialist, MinePro Services, with a more effective tool set to investigate a dipper drop incident. Raba was asleep at home when the mine called to report that a shovel had shut down after experiencing an uncontrolled dipper drop. With no prior training on the system, Raba quickly logged on to it from his home computer in Wyoming and was able to see real-time operating data on that specific shovel.
From experience, Raba knew to look at the hoist system. Because the Remote Health Monitoring system was capturing and archiving hundreds of data points from the shovel, Raba was able to quickly find the fault associated with the shutdown and use RHM’s analytical tools to analyze the data leading up to the fault. Within the hour, Raba was able to diagnose the problem. The data that the system provided indicated that the shovel event was induced by operator action rather than a system failure. Equally important, the data indicated that it was safe to restart the shovel.
“Without Remote Health Monitor in place, I would have had to drive an hour to the mine and hope the operator that was running the shovel during the fault was on shift and find out what took place,” Raba said. “I would then have to hook up a laptop and hope that everything was set up right to capture the correct data.”
The shovel was returned to service within six hours. “At the time, we probably had this tool for about a month,” Hanson said. “This is a breakthrough solution.”
Typically when a dipper drop occurs, a significant effort is required to investigate and determine the root cause of the event. Not only must P&H MinePro staff visit the mine, the shovel remains down for the duration of the investigation, which can take anywhere from one to three days to perform. Operating costs vary from mine-to-mine, but shovel downtime at current market rates costs a mine approximately $50,000 every hour in lost production.
The investigation requires significant time and effort to recreate and understand the conditions at the time of the dipper drop. Physical inspection of the shovel looks for damage that may be a cause or result of the event. The shovel operator is interviewed in order to understand the events leading up to the dipper drop. P&H MinePro staff may sit on the shovel and either wait for another incident to occur or try to recreate the original incident. During this time, they connect a laptop to the shovel in an effort to collect the data points that they believe will help them to understand the incident. If their best guess is wrong, the data will be useless. It is often difficult or impossible to fully understand the root cause behind the event.
This particular event involved an overload on the dipper, where the shovel was hoisting through the bank. A boulder was dislodged and fell into the dipper. The operator full lowered quickly, but gravity took over. The electrical system wasn’t able to handle the acceleration and the increased load. It was too close to the ground. The control system recognized this and shut it down. Gravity took over and the dipper dropped.
The Remote Health Monitoring system saved the mine 24 to 72 hours of shovel downtime--time that would have been spent diagnosing and recreating the original event with often inconclusive results. RHM allowed Raba to quickly provide a more reliable diagnosis of the root cause of the dipper drop event without a trip to the mine or extensive downtime. Because of RHM’s comprehensive data collection, Raba was able to investigate the original dipper drop incident itself instead of data collected from attempts to recreate the incident. He had immediate, remote access to the actual data from the actual event and was able to quickly and reliably diagnose the root cause.
Raba determined that the fault occurred due to operator error, allowing the mine to address a training issue. Even more importantly, he knew that the shovel was operating properly and recommended that it continue operating--avoiding the significant downtime and production losses usually involved in machine troubleshooting.
This article was adapted from a presentation, “Leveraging Remote Health Monitoring Technologies to Reduce Mining Equipment Cost/Ton,” that Curt Hanson, director-product management, P&H Mining Equipment Co., made at E&MJ’s Haulage & Loading conference, which was held during May in Phoenix, Ariz.