With almost all tire prices continuing to increase, demand is simply not keeping up with supply as some large mining tires have already passed the $100,000 per piece on the spot market (see article here). 
The solution? Polyurethane Tire Fill will extend tire life, increase productivity and reduce the cost of tire repair or replacement.
See here for what mining equipment can be tire flatproofed:
Commonly referred to as foam fill, tire fill, and poly fill, Arnco’s patented products reduce downtime related to punctured tires or flat tires. The liquid polyurethane is pumped into the tire through the valve stem until it replaces all of the air which now results into a solid tire, but with a softer ride than a solid rubber tire. The result are flatproof tires that improve the productivity of the equipment.