ROV for pre-mine-dive application?

[Therrin]

Howdy folks,

Been interested in building a ROV.

I already got my feet wet, quite literally. I do professional mineshaft exploration. There's a certain mine that is semi-flooded all throughout that I had been to several times, and recently (just the other night) I ended up doing some mine diving in a fully flooded section. Made a plan, dove the plan, have new info, need a new plan for the followup dive.

However. Some of this stuff I'd really like to send a ROV down into *FIRST*. Both for clarification of how extensive these areas are, and to get some good shots/video without much silting.

The location for this dive was about 1/3rd of a mile into a mine, inside a mountain. Had to schlep all the gear in and set up. There are other spots in this mine which have potential as well. But all systems would have to be battery powered, ultimately.

This is the water entry point:


We did some quick-n-dirty video the other night, it's here:

https://www.youtube.com/watch?v=fjnXIr9ng6c

Question:
What are the major obstacles I'd need to face to use a ROV in this location?
What style of ROV would be best suited to this type of application?

I appreciate any input y'all have, thanks!

[Triton]

Hi Therrin,

although I don't really have any experience in cave (or mine) diving it sounds quite hard to dive an ROV in such a place.
The first thing that crosses my mind is how you'll manage to handle the ROV in that maze and not entangle the tether.
It sounds quite difficult. And if you're going to send the ROV 1/3 of a mile in a cave, then it sounds quite impossible to navigate it back without being cought on something. Anyway, I can't be sure. Just sharing thoughts.

Apart from that, I can't see any other special problems.

It must be quite dangerous down there! Take care...

Triton

[scubersteve]

I agree that how you handle the tether will be rather critical.
I would be tempted to go with on-board power to allow you to keep the tether light and flexible.
If you use a ppn to pwm converter or a dsc capable rc transmitter and receiver you only need two wires for control and another two for video.
Although a second rear-facing camera to help keep track of your tether might be a good idea and would add another two wires.
So up to six small gauge wires.

What kind of depth do you expect to have to deal with?

[fluxno]

The OpenROV (www.openrov.com) operates on 2 wires(ethernet over hacked powerline adapters) and onboard batteries.
there are in progress a onboard charging system, so we can use the tether to transmit some power down to the rov for charging the batteries(extending the operation time)
it only has 1 camera now, but some small software changes can get two cameras to work.
the openrov is based around a Beaglebone linux computer with a "cape" that has a onboard arduino mcu, that controlls of-the-shelf RC car speedcontrollers and RC plane brushlessmotors.

I think some recent trial was done with a 28 or 30awg cable over a distance of 100meter, and this worked fine.

[scubersteve]

What is the purpose of professional mineshaft exploration?
As in are you looking for something?
Just curious.

I find myself envious of those who have a clear objective/purpose for their rovs.
Mine have been more of an engineering exercise so far.

[jacko1]

Hi!

Very intresting project!

With some minor cave diving training and experience some thoughs came in my mind:

As a cave diver you know this stuff already, but anyway:
I think that there is very good possibility to get entagnled, if the cave is not straight tube since the tether will be pushed against bottom, ceiling and walls as your rov goes up and down and takes turns. If your rov gets entangled on something and you try to get rov free, you need to navigate in very delicate way not to stirr the bottom.
If there is complete siltout, you cannot see anything and untangling the rov would be impossible.

So you would need very precise system to manouver in all directions. Maybe just get yourself a rebreather and go there yourself?

-J