Need help building custom RZR for Gold Prospecting

I’m building a vehicle which is going to be used ONLY to drag a metal detector drag coil through the goldfields of Western Australia.

The terrain I am driving on is flat, some small rocks but mostly clay like mud about 2-3 inches deep max in most places on a hard rocky base. I will be driving it only at 5 miles per hour at all times. There is no time that I will be going faster than that.

I want to use the RZR because it has lots of clearance to run big tires. If there is another ATV that you can recommend as an alternative I would be interested in knowing. My biggest problem is clearance for running huge tires.

I intend on running 39 inch tires… YES 39 inch. The reason for this is for ground clearance. The tires are skinny, the size will be 8.3 inches wide 995mm (39 inches). Do you think that the axles are strong enough to run such big tires? Like I said, I am driving at walking pace only at all times. I may decide to use wider tires if they are not too heavy.

These are the tires I am going to use. I am going to mount them on Crush Lock rims so that they can be run with out air (punctures are inevitable as there are lots of spikey things out there)

Crush lock rims similar to these but 24 inches

Any advice would be good, especially about stuff that may break.

This is the terrain I am going to be driving over, it looks hard but it is actually super slippery clay about 2-3 inches deep on a hard pack base. (hence the tractor tires) The terrain is almost impossible to traverse in a 4×4 without diff locks as the tire treads get clogged with clay and turn into a racing slick.

Somewhere out there are HUGE gold nuggets worth millions and I want to find me one.

I will be towing a rubber mat about 15 feet long with a metal detector coil nearly 3 feet wide. Total weight of that is about 100 pounds.