Cleaning a Piece of Machinery Led to a Crush Injury: Case Study
It is amazing to think that, 3000ft below the surface, underneath an old coal mine, methane gas is present. Called Coal Bed Methane (CBM), this gas has the potential to be a great source of energy for the UK. In fact, 10% of gas in the USA comes from CBM.
Extracting the gas is a very simple process. Firstly, a hole is drilled into the coal seam. Because these geological seams are deep underground, they fill up quickly with water. Actually, it is the water that keeps the methane gas from escaping to the surface. So the second step in the process is to install pumps into the newly drilled holes, which pump out the water, thereby releasing CBM gas.
At the top of the hole, at ground level, a piece of machinery with a rotating shaft is installed. This shaft drives the pump and usually the machinery is left turning 24 hours per day. Of course, because the shaft is continually rotating, the area around the machinery is well fenced off to prevent anyone getting close to the hazard.
A Straightforward Task...It was Joe’s job to measure the amount of rotation of the pump, to ensure that the pump was running properly. To do this, a white disc was fitted to the shaft so that an electronic device could be used to ‘read’ off the disc. But, because the machinery is near to ground level and because the pump is constantly pumping dirty water from deep underground, the shaft at the surface becomes clogged and quite messy, making it difficult to take readings from the white disc. So Joe always had to use a rag to clean the disc before taking his readings.
The procedure for this task was quite straightforward. The first step was turn off the pump. The next step was for the operator to fully isolate the electrical supply by turning a hydraulic lever to the off position. Finally, the electrical generator that supplied power to the pump had to be completely shut down. Only when the three steps had been taken should operators go near to the rotating shaft. However, this took time. It was much quicker to simply turn off the power to the rotating shaft and then clean the spindle quickly before turning the power back on again. However, taking this short-cut meant that power still flowed to the machinery, even although the pump had been turned off.
A Straightforward Task Gone WrongOn this occasion, Joe was very unlucky. He turned off the pump but didn’t shut down the generator. He wrapped a rag around his wrist and started to clean the white disc. A few seconds later, the spindle started to turn. Joe wasn’t quick enough to get his hand free – the rotating spindle caught the rag and started to pull it around. The rag gripped tighter and tighter around Joe’s wrist and hand, breaking one bone after another.
Joe could feel the bones snapping, the pain was intense. He shouted for help but because of the remote location of the site, there was no one to hear his call. He couldn’t escape the rotating spindle and he didn’t have the strength to hold back the power of the machinery. Tighter and tighter it gripped and bone after bone was shattered.
Luckily, two boys out for a cycle ride heard his cry for help. They rushed over to the machinery and, instructed by Joes' frantic calls, they managed to work out how to turn off the pump. Finally the rotating shaft stopped turning. Joe was free at last. But not before his wrist had been dislocated, eight bones in his hand broken and serious bruising and nerve damage to his arm.