Hello to all.

[barryn56]

I manage a small R&D company in Brisbane. We generally work on oil and gas industry on developing new downhole sensors. I have a B.Sc. in Physics and an M. Eng. in Petroleum Reservoir Engineering, with 25 years experience in the international upstream petroleum service industry. My company staff includes a mechanical and electronics engineer.

We have recently been looking at other industry "issues" that are looking for solutions. The one related to mining is a method to identify failed rock bolts and transmit the information from the bolt by a radio frequency signal. We're interested to get community feedback on the usefulness, or otherwise, of this sort of product.

Barry

 

[AtomRat]

Like a frequency xray through bolts to find faults? Sounds pretty cool!

Are you testing bolts before, after or in use?

Can you do other tests using the same analyzer to find hidden breaks / cracks, or other useful info?

Are the rocks wireless sensors or will bolts be tested individually?

 

[Tathradj]

Like a load sensor?

 

[barryn56]

Hi Guys.

The solution we're looking at is to determine failure somewhere along the length of an installed bolt. It may be corrosion, stress cracking, shear failure - so not just tensile load failure, which stress/strain measurement might show. There are plenty of easy strain washer solutions to that, though they may have their own issues, such as power requirement, etc. Our approach would be something that fits on the end of the bolt and can run for 10 years off a small internal battery.

The current requirement is to test new bolt installations (i.e. we have to modify the bolt, so if it's already installed that would be expensive) and then continuously monitor the bolt integrity without requiring any maintenance or external power supply. If the bolt integrity is compromised (e.g. eaten partly through by corrosion, or sheared, etc.) then the unit would send an RF signal to a receiver and identify which bolt has problems.

To examine bolts externally would require a neutron source, as x-rays would not penetrate, and we're trying to avoid a lot of manual intervention which is a) expensive and b) only periodic, so may not catch a problem early enough. However, I understand there is an apparent need to examine installed bolts, so I'm considering some techniques that might work. The existing system on the market uses a geophone and a hammer, using reflected sound waves to identify bolt length and some defects, such as breakage. That method could be improved upon, but I'm thinking there may be other suitable techniques which would be much faster.

Thanks for you comments.

Regards,

Barry

 

[Tathradj]

Maybe a small hollow section on the bolt that contains a small electronic circuit.
I see with a lot of mining that the bolts are inserted with mesh.
Bolt = Anode.
Mesh is cathode.
Fire a small charge through the bolt and if it changes above a certain thresh hold, resistance?.
Might be a problem with fluid ingress or high iron content. ??
.
.

Or,
Coat the bolt with a suitable medium.
Install it, Number it, Measure it. Then with a small hand held device, walk along and "Blit" each bolt comparing them with their installed values.
Maybe with the "Talking Heads" , if their is some thing going on to begin with, Measuring them electronically will show up more issues.
I would just hate to have too much RF running around explosives. Mind you it would be very passive but...