Solutions for Rod Jamming

• 25 July 2017
• Uncategorized
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Have you had any experience of rod jamming during your drilling operation? There can be many factors; one is the collapse of the drilling hole; another is the cavity space inside the drilling hole. Furukawa, one of the leading rock drilling machinery producers can introduce some solutions and will explain details of these factors.

1. Drilling Hole Collapse:

Sometimes, the ground surface of the bench may be loose and fragile up to one or two metres in depth after blasting. In this case, the hole collapse often occurs during the drilling. As a result, several rocks fall off the wall of the hole. The falling rocks get stuck between the hole and the rod or bit. The rod gets jammed and cannot be pulled out. It is quite hard work to recover from the jamming and it robs your job and production of expensive and valuable time.

2. Cavity space inside drill hole:

If there are any cavities inside the hole during the drilling operation, it affects flushing performance. The cavity interrupts cutting rocks going outside of the hole. Because a lot of flushing blow power escapes into the space of cavity, it reduces power. As the result, a lot of cutting rocks cannot go outside of the hole and remain inside which results in the jamming of your rod. In addition, the cavity causes a hole deviation.

How to solve these problems? One solution is to use clay.

Tamp clay in the hole after drilling the first metre or around by collaring drilling Proceed to drill with no rod rotation by one metre or around.

Clay is pushed to the hole wall and it fixes the entrance of the hole and its wall. The fixed wall prevents any more collapse of the hole wall. It can be free from any stress of rod jamming caused by hole collapse.

If there are any cavities inside the hole, clay can help to fill the spaces and gaps of the cavity. As a result, the cavity disappears, and all flushing blow power can go outside of the hole straight and directly to achieve a smooth drill operation.

In case of no clay being available on the site, there are two ways to avoid these factors. One is to use water which also helps to fix the hole wall. Your drill may have a water tank and mist flushing system as optional equipment. The equipment supplies and sprays from the face of the bit through the rod. In the operator cabin of the drill machine, the drill operator can control spraying water to the hole.

Water is not effective itself against cavity problems but can be mixed with cutting dust, which is exhaust from the drill machine dust collector. The mixed material becomes like clay and can be put in the hole to fill the cavity space and fix the hole wall like clay.

These solutions are simple, but we believe they help a lot for daily operations. If rod jamming is reduced, the total drilling time becomes faster and productivity increases. When drilling suffers rod jamming caused by a hole collapse or cavity space, we recommend trying these solutions.