Maintaining stringent safety regulations and focused efforts to minimise downtime is imperative to keeping mines running both safely and productively. When it comes to conveyor belts, there are numerous safety standards in place (such as isolation & minimising product spillage) to ensure that they continue to run efficiently whilst also ensuring that mines maintain a safe working environment. But what happens when safety policies require conveyor belts to shut down? Are mines inevitably going to need to choose between safety and productivity? There is no grey area here and site policies are designed to give the operator no choice.
Mining-technology spoke with Russell Norman, product designer for Track Straight, and Darren Waters, business development manager at Schlam Group, about how the Track Straight conveyor belt correction system manages safety and productivity at mining sites.
How much of an impact do conveyor belt related issues have on productivity? Are workers taking unnecessary risks to avoid downtime?
Darren Waters: Conveyor tracking issues can be the cause of many problems. When they arise, operators must make a choice between creating further downtime to isolate the conveyor to force a tracking frame, or take risks and track the conveyor while it is running within inches of moving components running at speeds of 10m/sec. Isolating conveyors is the safe way to do this work, but it can create further issues if the conveyor belt is tracked too far or the incorrect direction, which is not identified until start up. Track Straight’s tracking tools allow the operator to make the changes and instantly see the belt correction take place. Once the belt is forced, the tracking tool flags a status change via the proximity switch that can be logged on overview software and identified for follow up at a planned maintenance interval. This allows businesses to plan repairs in a safe way rather than during breakdowns, which reduces the temptation for unsafe behaviours that cause incidents and injuries.
Russell Norman: Conveyor downtime has been a major contributor to overall fixed plant downtime in most mines we have dealt with. Conveyor downtime can be further broken down to its three biggest factors; chute blockages, idler change out requirements and belt drift events.
Our product aims to reduce downtime caused by belt drift events, as well as eliminate current unsafe practices that can happen when these events occur.
What are these current unsafe practices?
RN: Some belt drift events can be rectified immediately by doing things such as removing build up from under a conveyor or adjusting a deflector plate. However, issues such as worn feed zones or uneven wear on a conveyor pulley can cause a belt drift that can’t be immediately rectified, so extra parts and labour have to be scheduled for the next periodical fixed plant shutdown.
During these belt drift events it is common practice to force the conveyor tracking frames by tying a rope between the frame and the conveyor structure to keep the conveyor belt running true until this scheduled downtime, and company policy is that the conveyor has to be isolated to force these tracking frames safely. This adds to the downtime of the event, but more worryingly, it is sometimes done while the conveyor is still running, putting personnel in close proximity to live rotating equipment.
How does the Track Straight system eliminate these unsafe practices?
RN: Our system retrofits to the conveyor tracking frame and sits in a neutral position until there is an event that would require the tracking frame to be forced with rope. When these events occur, the Track Straight system can be utilised safely while the conveyor is running to force the conveyor belt in the desired direction. This eliminates both the need for isolation and the use of ropes, resulting in a safe and engineered way to force tracking frames.
What components of the Track Straight system keep the operator safe while making adjustments to a live conveyor? What site-specific safety regulation did you have to consider?
RN: When designing the Track Straight system, keeping the operator safe was our first priority. The use of a worm drive gearbox means that there will be no force feedback applied from the tracking frame back through to the handwheel that the operator uses to make adjustments. We also included a clutch mechanism so we can set the maximum amount of force being applied to the tracking frame to eliminate any mechanical damage to the frame and the Track Straight unit.