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Detecting Defects – How to Avoid Breakdowns and Downtime, Part I

The following is adapted from Simplifying Mining Maintenance.

The first step to improving mining maintenance is addressing breakdowns. Managers tend to think planning and scheduling is the first step to reducing unscheduled downtime, but planning and scheduling only help once the basics are in place. If these fundamentals aren’t in place, interruptions will continue to happen.

There are many explanations for why mines have excessive unscheduled and reactive downtime. In this article, we’ll look at three problems surrounding defect detection and see how we can steer clear of dangerous situations and reactive downtime.

Problem #1: Defects don’t get into the system

Maintenance managers can avoid mishaps that cause reactive downtime if their tradies identify problems during scheduled services and record those defects in the computerised maintenance management system. If the people doing inspections find faults, they can’t just note them on service inspection sheets. They have to put the issue in the CMMS.

This vital step allows planners to schedule repairs. Without it, no one knows about the defect until there’s a breakdown or at the next scheduled inspection, when it is found to be out of specification and needs to be replaced immediately. This triggers a reactive job because people do not have the resources ready to correct the conditions.

Here are two real-life examples of this problem. These two examples show service sheets listing serious defects. Mechanics reported these problems, but there were no subsequent notifications or work orders raised in their maintenance systems. No one addressed the problem, which could lead to breakdowns or a fire on the equipment.

The first example is a failing fuel hose. Someone inspected the engine on a mining truck and noted that the fuel hose was wearing out. A cracked fuel hose could leak and spray fuel onto the hot parts of the engine and cause a fire. This worn-out fuel hose wasn’t raised as a defect in the system nor repaired immediately during the service.

There could be many reasons for this: The inspector forgot the issue after making many similar reports, or the inspector assumed someone else would make the subsequent notification. Whatever the reason, no one recorded the problem in the system, and no one took responsibility for ensuring corrective maintenance was scheduled.

The other example is from the same site. An electrical wiring harness was rubbing on a high-pressure fuel hose. An inspector noted this problem but never put it in the system.

Errors like these are common and many mines have no clear system to prevent them. In a small organisation, where a maintenance person makes a mental note of a problem and ensures it’s fixed before it worsens, there may be no need for a system-based solution. However, a company with large fleets of equipment can face serious consequences if these issues persist. Large companies need reliable systems that everyone uses so simple repairs don’t lead to debilitating breakdowns.

Solution #1: Working agreements

The first step to solve this problem is for everyone to agree on a method to overcome the problem. This method might be as simple as writing a notification number next to every defect that is identified so that someone else can verify that it gets done every time the service is performed. The specific solution is not as important as the fact that everyone agrees to do it the same way so that we all know what is going on. In Bluefield, we call these small agreements within the teams working agreements.

Developing these working agreements requires getting all of the crews together from different rosters, particularly the supervisor from each roster and the people who form part of the natural work team. This collaboration can also include the planners and engineers for that team. The leader (superintendent) must be part of the discussion.

Everyone must feel that they have had an opportunity to provide input. The decision can’t be made by supervisors or superintendents and delivered to crews. Crew members need to own the solution. If you just tell them what to do without enabling them to decide on the solution to the problems, it takes the ownership away from the people who have to implement the solution.

Removing ownership this way makes the leaders’ job more difficult because now they must hold crew members accountable for something the crew members may not see as necessary. However, if there is ownership across all shifts, things will change—even if the working agreement is just scribbled on a piece of paper.

The goal is to ensure that all defects are consistently and verifiably recorded on service sheets and acted on. Some defects do not require subsequent action, such as when there already is a job for it in the system, but the team needs to be conscious of this.

Problem #2: Defects don’t get identified

This is when defects are overlooked or ignored. An inspector following an inspection sheet telling him to look for rubbing hoses, leaks, or loose components reports that everything is good when it isn’t. There could be many reasons for this:

  • The inspector didn’t notice a defect or is unaware that the condition is substandard and might cause a breakdown.
  • The technician has a bad attitude and doesn’t care. (This is very rare but can occur on sites with morale problems)
  • The technician assumes the poor condition of the equipment is acceptable. People generally adopt the standards they find when they arrive, so if those standards are low, that’s what the inspector will allow. It requires the team to make make it clear what is acceptable.

Some inspectors overlook problems because they don’t recognise these defects are causing breakdowns. Sometimes the standards are written on the service sheets and inspectors still don’t identify the defect. But most often unidentified defects reflect the low standards adopted by maintenance crews at a particular site.

Solution #2: Discuss equipment condition every day

Again, the solution to this problem is to get all people to agree on what standards are acceptable. Maintenance crews need to discuss the quality, standards, and conditions of the equipment every day. Some of the sites that have achieved the most rapid improvements in equipment availability (from 84% to 90% in less than twelve months) implemented a process where they shared photos of bad practices and good practices at their shift start meetings. This ritual changed the culture because the mechanics wanted to be recognised for good work and did not want to let their team down.

Most mining sites have morning meetings where the main topic is safety. The same conversation can also focus on quality and standards.

Another way to improve standards is to setup a failed parts inspection area. People can examine the parts and service sheets and discuss why a piece of equipment broke down. Everyone learns from the experience.

Some companies have a safety cross as part of their lean board, and these operations often set up a maintenance execution quality cross too. The key here is for teams figure out their own way to raise standards; they are more like to take responsibility if the solution comes from them and not from the top.

Problem #3: Tolerable defects are not monitored and managed

Often you find a defect—such as a small crack that seems to be getting worse—that doesn’t need to be fixed right away. The machine can continue operating, but you must keep an eye on these defects and manage the problem until the next scheduled service.

When that time comes, you can address it with adequate time and care. If the problem worsens, you can move up the date of the next scheduled maintenance.

Recently we had a coupling that was making a loud noise and overheating. Workers filled it with grease, which cooled it down and stopped the racket. I told them to keep operating until the next shutdown in ten days but to examine it frequently.

They treated it as a tolerable defect. They inspected it every couple of hours, and as their confidence grew in the temporary repair, they decreased the inspection frequency. If it started rattling or overheating again, they’d shut it down and add more grease. All crews monitored the problem and the coupling made it to the next scheduled outage.

It’s OK to manage these flaws until you have the people and parts to fix the defects during a scheduled service. Every site has these defects, but they often aren’t managed well, such as when the roster changes and the departing team forgets to warn the arriving team about the defect and how to manage it. A breakdown inevitably occurs.

Solution #3: Shift-start agenda

The solution is to have an area on the shift-start agenda—a whiteboard or sheet handed out to everyone—that lists all the tolerable defects being monitored. Everyone must know the condition of the machines and be aware of potential defects that could cause a breakdown if not managed. The list should define who will check on the defect and how often. Crews should time the inspection to coincide with another downtime event, such as refuelling. Good communication can prevent a costly breakdown.

For more advice on detecting and reporting defects in your mine, you can find Simplifying Mining Maintenance on Amazon, google ebooks or simplifyingminingmaintenance.com.

Gerard Wood is one of the mining industry’s foremost authorities on proper mining equipment maintenance. In his long career, Wood has been all over the world, working his way up from an electrician’s apprentice to a maintenance manager with advanced degrees in electrical engineering and business. As managing director for Bluefield AMS, Wood helps the world’s largest mining companies keep their machines running with a simple, practical approach that saves money and improves equipment reliability.