Thread: Major engineering challenge

Originally Posted by FiReSTaRT

By the way, is there a fishing line that can pull about 250lbs of weight?

what about Spectra cord?

At 216lbs it MIGHT do the trick. We also saw some cheap kevlar kite line that would be cheap enough to braid.

check climbing and camping suppliers

I'd be surprised if there wasnt an OTS (off the shelf) product that would do the job.

Typically for pulling cable through duct, one would utilize a vacuum at the receiving end to draw a partially inflated balloon with a pull string attached (if the pull string was not installed with the duct). The cable is attached to the pull string and pulled through the duct. If the cable diameter approaches the diameter of the duct, or the duct run is long, one would use Polywater to lubricate the cable.

The application Ilija has would be something quite different. Instead of drawing the balloon with pull string with a vacuum and pulling the cable through, one would have to 'push' the cable (kinda like pushing rope). Since you cannot push flexible cable any real distance, you have to figure a way to pull the cable without a pull string from the cable spool side.

To do this, I would utilize some sort of 'bullet shaped' head (as mentioned earlier in this thread) that has the ability to store and release compressed air. I would also cover the head and cable with Polywater to reduce friction. The issue with this is: how much compressed air is needed, and what is its effectiveness?

Another option is to utilize the water drill to push the aforementioned head (at reduced pressure). The effect would be the same.


Bob

What do I know, I'm an Electrical Engineer, not a Mechanical Engineer.

I know a mechanical engineer who made a good living doing electrical engineering design work. I don't see why an electrical engineeer couldn't go the other way

Ilja,

JMHO, but until you definitively answer whether the hole is blind or open at the far end, and whether intrinsic safety is involved (so a spark won't set off an explosion if gas has infiltrated the tunnel), I don't think you're going to necessarily get solutions that fit your problem.


You stated at the beginning that this would take a technological breakthrough... is this because no one has figured a way to do this at all??? Or, is this a case of searching for a cheaper way???

I am not sure if it's an open hole or not. The person I'm working with on the project has been MIA due to a family situation. I'm guessing it's not open but that's really just a guess. As for safety measures.. That's also a bit of an unknown I'll have to ask him about.. I'm thinking that sparks aren't that much of a no-no as the aparatus would be running electric currents into the ground.
AFIK it hasn't been done for this sort of exploration, period. The most that has been done was about 1/3 of the goal. Even that would be a significant step.

How was the hole made? If it's a blind hole, as it seems to be and you want to put some sort of fishing/downhole tool (sorry I don't know the mining industry term) in there why couldn't the tool/sensor be incorporated into a drilling tool, compressed air mole or whatever so both drilling and testing would be done at the same time?

The drilling was done with water. As for fishing downhole tools.. I am assuming they would need the assistance of gravity to work.

Originally Posted by FiReSTaRT

I am not sure if it's an open hole or not.

I suspect you're right that it's closed, but please confirm when you find out for sure.

Originally Posted by FiReSTaRT

As for safety measures.. That's also a bit of an unknown I'll have to ask him about.. I'm thinking that sparks aren't that much of a no-no as the aparatus would be running electric currents into the ground.

Sparks in a mine are generally a no-no... gas + sparks = explosion =

Intrinsic Safety is all about limiting energy to something less than can create a spark... in rough terms, that means limiting everything to about 28volts and a little over 200ma. If the device requires more energy than that you can enclose it in a sealed explosion proof enclosure/housing. There's a lot more to it, but you get the idea. Here's a short overview article for those unfamiliar with IS.